[PATCH v6 0/3] ublk: enable zoned storage support

[PATCH v6 0/3] ublk: enable zoned storage support

[Andreas Hindborg]

From: Andreas Hindborg <a.hindborg@samsung.com>

Hi All,

This patch set adds zoned storage support to `ublk`. The first two patches do
some house cleaning in preparation for the last patch. The last patch adds
support for report_zones and the following operations:

 - REQ_OP_ZONE_OPEN
 - REQ_OP_ZONE_CLOSE
 - REQ_OP_ZONE_FINISH
 - REQ_OP_ZONE_RESET
 - REQ_OP_ZONE_APPEND

A user space component based on ubdsrv is available for testing [1] with the
"loop" target.

Read/write and zone operations are tested with zenfs [2].

The zone append path is tested with fio -> zonefs -> ublk -> null_blk.

The implementation of zone append requires ublk user copy feature, and therefore
the series is based on branch for-next (6afa337a3789) of [3].

Changes for v6:
 - Style fixes
 - Document __ULK_IO_OP_DRV_*
 - Remove "depends on BLK_DEV_UBLK && BLK_DEV_ZONED" from kconfig
 - Rework `get_nr_zones()`
 - Merge `ublk_disk_set_zoned()` and `ublk_dev_param_zoned_apply()`
 - Fix an exit condition bug in `ublk_report_zones()`
 - Only call `ublk_set_nr_zones()` if device is zoned
 - Change a config gate from BLK_DEV_ZONED to BLK_DEV_UBLK_ZONED
 - Simplify `ublk_alloc_report_buffer()`
 - Simplify `ublk_revalidate_disk_zones()`
 - Remove redundant parameter check from `ublk_dev_param_zoned_apply()`
 - Remove redundant zone size check from `ublk_set_nr_zones()`
 - Remove `ublk_zoned_commit_completion()` and open code instead
 - Do not add an extra translation unit (v5 added an extra C file)

[1] https://github.com/metaspace/ubdsrv/tree/1ac32cf841b07259cf8b075a5c0006803eeb3981
[2] https://github.com/westerndigitalcorporation/zenfs
[3] https://git.kernel.dk/linux.git

Andreas Hindborg (3):
  ublk: add opcode offsets for DRV_IN/DRV_OUT
  ublk: add helper to check if device supports user copy
  ublk: enable zoned storage support

 drivers/block/Kconfig         |   4 +
 drivers/block/ublk_drv.c      | 348 ++++++++++++++++++++++++++++++++--
 include/uapi/linux/ublk_cmd.h |  48 ++++-
 3 files changed, 383 insertions(+), 17 deletions(-)


base-commit: 3261ea42710e9665c9151006049411bd23b5411f
-- 
2.41.0

[PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Andreas Hindborg]

From: Andreas Hindborg <a.hindborg@samsung.com>

Ublk zoned storage support relies on DRV_IN handling for zone report.
Prepare for this change by adding offsets for the DRV_IN/DRV_OUT commands.

Also add parenthesis to existing opcodes for better macro hygiene.

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
---
 include/uapi/linux/ublk_cmd.h | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 4b8558db90e1..2ebb8d5d827a 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -229,12 +229,22 @@ struct ublksrv_ctrl_dev_info {
 	__u64   reserved2;
 };
 
-#define		UBLK_IO_OP_READ		0
+#define		UBLK_IO_OP_READ			0
 #define		UBLK_IO_OP_WRITE		1
 #define		UBLK_IO_OP_FLUSH		2
-#define		UBLK_IO_OP_DISCARD	3
-#define		UBLK_IO_OP_WRITE_SAME	4
-#define		UBLK_IO_OP_WRITE_ZEROES	5
+#define		UBLK_IO_OP_DISCARD		3
+#define		UBLK_IO_OP_WRITE_SAME		4
+#define		UBLK_IO_OP_WRITE_ZEROES		5
+/*
+ * Passthrough (driver private) operation codes range between
+ * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
+ * operations and between __UBLK_IO_OP_DRV_OUT_START and
+ * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
+ */
+#define		__UBLK_IO_OP_DRV_IN_START	32
+#define		__UBLK_IO_OP_DRV_IN_END		96
+#define		__UBLK_IO_OP_DRV_OUT_START	__UBLK_IO_OP_DRV_IN_END
+#define		__UBLK_IO_OP_DRV_OUT_END	160
 
 #define		UBLK_IO_F_FAILFAST_DEV		(1U << 8)
 #define		UBLK_IO_F_FAILFAST_TRANSPORT	(1U << 9)
-- 
2.41.0

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Damien Le Moal]

On 7/6/23 22:09, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> Ublk zoned storage support relies on DRV_IN handling for zone report.
> Prepare for this change by adding offsets for the DRV_IN/DRV_OUT commands.
> 
> Also add parenthesis to existing opcodes for better macro hygiene.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> ---
>  include/uapi/linux/ublk_cmd.h | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 4b8558db90e1..2ebb8d5d827a 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -229,12 +229,22 @@ struct ublksrv_ctrl_dev_info {
>  	__u64   reserved2;
>  };
>  
> -#define		UBLK_IO_OP_READ		0
> +#define		UBLK_IO_OP_READ			0
>  #define		UBLK_IO_OP_WRITE		1
>  #define		UBLK_IO_OP_FLUSH		2
> -#define		UBLK_IO_OP_DISCARD	3
> -#define		UBLK_IO_OP_WRITE_SAME	4
> -#define		UBLK_IO_OP_WRITE_ZEROES	5
> +#define		UBLK_IO_OP_DISCARD		3
> +#define		UBLK_IO_OP_WRITE_SAME		4
> +#define		UBLK_IO_OP_WRITE_ZEROES		5
> +/*
> + * Passthrough (driver private) operation codes range between

This is unclear... Here, what does "driver" refer to ? If it is the ublk
kernel driver, than these commands should not be defined in the uapi
header file, they should be defined in drivers/block/ublk.h. However, if
these are for the user space driver, like all the other operations, then
let's clearly state so. But then, I still not understand why these need
a different naming pattern using the "__UBLK" prefix...

> + * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
> + * operations and between __UBLK_IO_OP_DRV_OUT_START and
> + * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
> + */
> +#define		__UBLK_IO_OP_DRV_IN_START	32
> +#define		__UBLK_IO_OP_DRV_IN_END		96
> +#define		__UBLK_IO_OP_DRV_OUT_START	__UBLK_IO_OP_DRV_IN_END
> +#define		__UBLK_IO_OP_DRV_OUT_END	160
>  
>  #define		UBLK_IO_F_FAILFAST_DEV		(1U << 8)
>  #define		UBLK_IO_F_FAILFAST_TRANSPORT	(1U << 9)

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Ming Lei]

On Fri, Jul 07, 2023 at 08:50:01AM +0900, Damien Le Moal wrote:
> On 7/6/23 22:09, Andreas Hindborg wrote:
> > From: Andreas Hindborg <a.hindborg@samsung.com>
> > 
> > Ublk zoned storage support relies on DRV_IN handling for zone report.
> > Prepare for this change by adding offsets for the DRV_IN/DRV_OUT commands.
> > 
> > Also add parenthesis to existing opcodes for better macro hygiene.
> > 
> > Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> > ---
> >  include/uapi/linux/ublk_cmd.h | 18 ++++++++++++++----
> >  1 file changed, 14 insertions(+), 4 deletions(-)
> > 
> > diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> > index 4b8558db90e1..2ebb8d5d827a 100644
> > --- a/include/uapi/linux/ublk_cmd.h
> > +++ b/include/uapi/linux/ublk_cmd.h
> > @@ -229,12 +229,22 @@ struct ublksrv_ctrl_dev_info {
> >  	__u64   reserved2;
> >  };
> >  
> > -#define		UBLK_IO_OP_READ		0
> > +#define		UBLK_IO_OP_READ			0
> >  #define		UBLK_IO_OP_WRITE		1
> >  #define		UBLK_IO_OP_FLUSH		2
> > -#define		UBLK_IO_OP_DISCARD	3
> > -#define		UBLK_IO_OP_WRITE_SAME	4
> > -#define		UBLK_IO_OP_WRITE_ZEROES	5
> > +#define		UBLK_IO_OP_DISCARD		3
> > +#define		UBLK_IO_OP_WRITE_SAME		4
> > +#define		UBLK_IO_OP_WRITE_ZEROES		5
> > +/*
> > + * Passthrough (driver private) operation codes range between
> 
> This is unclear... Here, what does "driver" refer to ? If it is the ublk
> kernel driver, than these commands should not be defined in the uapi
> header file, they should be defined in drivers/block/ublk.h. However, if
> these are for the user space driver, like all the other operations, then

Like normal IO, these passthrough requests needs userspace to handle too,
usually they just belong to specific ublk target, such as report zones.,
so here it is part of UAPI.

But yes, we should document it clearly, maybe something below?

	Ublk passthrough operation code ranges, and each passthrough
	operation provides generic interface between ublk kernel driver
	and ublk userspace, and this interface is usually used for handling
	generic block layer request, such as command of zoned report zones.
	Passthrough operation is only needed iff ublk kernel driver has to
	be involved for handling this operation.

> let's clearly state so. But then, I still not understand why these need
> a different naming pattern using the "__UBLK" prefix...

I think __UBLK just meant we don't suggest userspace to use it directly,
since the added macros are just for making ranges for DRV_IN and DRV_OUT,
so we can check command direction easily be using this start/end info in
both sides.


Thanks, 
Ming

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Damien Le Moal]

On 7/7/23 09:59, Ming Lei wrote:
> On Fri, Jul 07, 2023 at 08:50:01AM +0900, Damien Le Moal wrote:
>> On 7/6/23 22:09, Andreas Hindborg wrote:
>>> From: Andreas Hindborg <a.hindborg@samsung.com>
>>>
>>> Ublk zoned storage support relies on DRV_IN handling for zone report.
>>> Prepare for this change by adding offsets for the DRV_IN/DRV_OUT commands.
>>>
>>> Also add parenthesis to existing opcodes for better macro hygiene.
>>>
>>> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>>> ---
>>>  include/uapi/linux/ublk_cmd.h | 18 ++++++++++++++----
>>>  1 file changed, 14 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
>>> index 4b8558db90e1..2ebb8d5d827a 100644
>>> --- a/include/uapi/linux/ublk_cmd.h
>>> +++ b/include/uapi/linux/ublk_cmd.h
>>> @@ -229,12 +229,22 @@ struct ublksrv_ctrl_dev_info {
>>>  	__u64   reserved2;
>>>  };
>>>  
>>> -#define		UBLK_IO_OP_READ		0
>>> +#define		UBLK_IO_OP_READ			0
>>>  #define		UBLK_IO_OP_WRITE		1
>>>  #define		UBLK_IO_OP_FLUSH		2
>>> -#define		UBLK_IO_OP_DISCARD	3
>>> -#define		UBLK_IO_OP_WRITE_SAME	4
>>> -#define		UBLK_IO_OP_WRITE_ZEROES	5
>>> +#define		UBLK_IO_OP_DISCARD		3
>>> +#define		UBLK_IO_OP_WRITE_SAME		4
>>> +#define		UBLK_IO_OP_WRITE_ZEROES		5
>>> +/*
>>> + * Passthrough (driver private) operation codes range between
>>
>> This is unclear... Here, what does "driver" refer to ? If it is the ublk
>> kernel driver, than these commands should not be defined in the uapi
>> header file, they should be defined in drivers/block/ublk.h. However, if
>> these are for the user space driver, like all the other operations, then
> 
> Like normal IO, these passthrough requests needs userspace to handle too,
> usually they just belong to specific ublk target, such as report zones.,
> so here it is part of UAPI.
> 
> But yes, we should document it clearly, maybe something below?
> 
> 	Ublk passthrough operation code ranges, and each passthrough
> 	operation provides generic interface between ublk kernel driver
> 	and ublk userspace, and this interface is usually used for handling
> 	generic block layer request, such as command of zoned report zones.
> 	Passthrough operation is only needed iff ublk kernel driver has to
> 	be involved for handling this operation.

Yes, that is better.

> 
>> let's clearly state so. But then, I still not understand why these need
>> a different naming pattern using the "__UBLK" prefix...
> 
> I think __UBLK just meant we don't suggest userspace to use it directly,
> since the added macros are just for making ranges for DRV_IN and DRV_OUT,
> so we can check command direction easily be using this start/end info in
> both sides.

Personally, I would still prefer to not add this "__" prefix as these
are operations that the ublk user driver will have to deal with, like
the other ones. So I do not see the point of that prefix. But no strong
feeling about that :)

> 
> 
> Thanks, 
> Ming
> 

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Christoph Hellwig]

On Fri, Jul 07, 2023 at 08:59:03AM +0800, Ming Lei wrote:
> > let's clearly state so. But then, I still not understand why these need
> > a different naming pattern using the "__UBLK" prefix...
> 
> I think __UBLK just meant we don't suggest userspace to use it directly,
> since the added macros are just for making ranges for DRV_IN and DRV_OUT,
> so we can check command direction easily be using this start/end info in
> both sides.

Folks, please stop coupling a uapi (or on-disk protocol) too tightly
to Linux internals.  Think of what makes sense as a communication
protocol, not what is an internal kernel interface.

REPORT_ZONES is a sensible command, and supported in ATA/SCSI/NVMe in
one way or another.  In Linux it is a synchronous method call right now
for one reason or another, and most implementation map it to a
passthrough command - be that the actual protocol command or something
internal for virtio.

So for ublk this is just another command like any other, that needs to
be defined and documented.  Nothing internal or driver specific.

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Ming Lei]

On Sun, Jul 09, 2023 at 11:52:39PM -0700, Christoph Hellwig wrote:
> On Fri, Jul 07, 2023 at 08:59:03AM +0800, Ming Lei wrote:
> > > let's clearly state so. But then, I still not understand why these need
> > > a different naming pattern using the "__UBLK" prefix...
> > 
> > I think __UBLK just meant we don't suggest userspace to use it directly,
> > since the added macros are just for making ranges for DRV_IN and DRV_OUT,
> > so we can check command direction easily be using this start/end info in
> > both sides.
> 
> Folks, please stop coupling a uapi (or on-disk protocol) too tightly
> to Linux internals.  Think of what makes sense as a communication
> protocol, not what is an internal kernel interface.
> 
> REPORT_ZONES is a sensible command, and supported in ATA/SCSI/NVMe in
> one way or another.  In Linux it is a synchronous method call right now
> for one reason or another, and most implementation map it to a
> passthrough command - be that the actual protocol command or something
> internal for virtio.
> 
> So for ublk this is just another command like any other, that needs to
> be defined and documented.  Nothing internal or driver specific.
 
Yes, that is exactly what we are doing.

The added macros of UBLK_IO_OP_DRV_IN_START[END] are just for supporting
more ublk passthrough commands, and the motivation is for running
check(such as buffer direction) in two sides easily.

However, I think it is just fine to delay to add it until introducing
the 2nd ublk pt command.

Thanks, 
Ming

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Christoph Hellwig]

On Mon, Jul 10, 2023 at 05:27:23PM +0800, Ming Lei wrote:
> Yes, that is exactly what we are doing.
> 
> The added macros of UBLK_IO_OP_DRV_IN_START[END] are just for supporting
> more ublk passthrough commands, and the motivation is for running
> check(such as buffer direction) in two sides easily.
> 
> However, I think it is just fine to delay to add it until introducing
> the 2nd ublk pt command.

The concept of a passthrough command just doesn't make sense for an
on the wire protocol.  It is a linux concept that distinguished between
the Linux synthetic command like REQ_OP_READ/WRITE/DISCARD etc that are
well defined and can be used by file systems and other consumers, and
ways to pass through arbitrary blobs only known by the driver.

Anything in a wire protocol needs to be very well defined in that
protocol completely indpendent of what Linux concept it maps to.
Especially as the Linux concepts can change, and fairly frequently do.

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Ming Lei]

On Mon, Jul 10, 2023 at 02:32:44AM -0700, Christoph Hellwig wrote:
> On Mon, Jul 10, 2023 at 05:27:23PM +0800, Ming Lei wrote:
> > Yes, that is exactly what we are doing.
> > 
> > The added macros of UBLK_IO_OP_DRV_IN_START[END] are just for supporting
> > more ublk passthrough commands, and the motivation is for running
> > check(such as buffer direction) in two sides easily.
> > 
> > However, I think it is just fine to delay to add it until introducing
> > the 2nd ublk pt command.
> 
> The concept of a passthrough command just doesn't make sense for an
> on the wire protocol.  It is a linux concept that distinguished between
> the Linux synthetic command like REQ_OP_READ/WRITE/DISCARD etc that are
> well defined and can be used by file systems and other consumers, and
> ways to pass through arbitrary blobs only known by the driver.
> 
> Anything in a wire protocol needs to be very well defined in that
> protocol completely indpendent of what Linux concept it maps to.
> Especially as the Linux concepts can change, and fairly frequently do.

Yeah, you are right wrt. linux pt command, and here we shouldn't use
the term of passthrough.

Actually the UAPI is trying to define interface between driver and
userspace, which is just like interface between driver and hardware, such
as, how nvme/sd_zbc is dealing with actual hardware wrt. reporting
zones.

Thanks,
Ming

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Andreas Hindborg (Samsung)]

Christoph Hellwig <hch@infradead.org> writes:

> On Mon, Jul 10, 2023 at 05:27:23PM +0800, Ming Lei wrote:
>> Yes, that is exactly what we are doing.
>> 
>> The added macros of UBLK_IO_OP_DRV_IN_START[END] are just for supporting
>> more ublk passthrough commands, and the motivation is for running
>> check(such as buffer direction) in two sides easily.
>> 
>> However, I think it is just fine to delay to add it until introducing
>> the 2nd ublk pt command.
>
> The concept of a passthrough command just doesn't make sense for an
> on the wire protocol.  It is a linux concept that distinguished between
> the Linux synthetic command like REQ_OP_READ/WRITE/DISCARD etc that are
> well defined and can be used by file systems and other consumers, and
> ways to pass through arbitrary blobs only known by the driver.

Yet most on-the-wire protocols for actual hardware does support this
some way or another. But I agree that for ublk it is probably not
needed. It would probably be easier to talk to the ublk daemon through
other means than passthrough in the block layer.

>
> Anything in a wire protocol needs to be very well defined in that
> protocol completely indpendent of what Linux concept it maps to.
> Especially as the Linux concepts can change, and fairly frequently do.

I somewhat agree in the sense that for consistency, we should either
move zone management commands to the DRV_OUT range OR move report_zones
out of this special range and just next to the zone management
operations. I like the latter option better, and I would love to see the
block layer do the same at some point. It feels backwards that
report_zones get special treatment all over the place.

Best regards,
Andreas

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Christoph Hellwig]

On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:
> Yet most on-the-wire protocols for actual hardware does support this
> some way or another.

Supports what?  Passthrough?  No.

> I somewhat agree in the sense that for consistency, we should either
> move zone management commands to the DRV_OUT range OR move report_zones
> out of this special range and just next to the zone management
> operations. I like the latter option better, and I would love to see the
> block layer do the same at some point. It feels backwards that
> report_zones get special treatment all over the place.

DRV_IN/OUT is purely a Linux concept.  It doesn't make any sense for
a wire protocol.

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Andreas Hindborg (Samsung)]

Christoph Hellwig <hch@infradead.org> writes:

> On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:
>> Yet most on-the-wire protocols for actual hardware does support this
>> some way or another.
>
> Supports what?  Passthrough?  No.

Both SCSI and NVMe has command identifier ranges reserved for vendor
specific commands. I would assume that one use of these is to implement
passthrough channels to a device for testing out new interfaces. Just
guessing though.

>
>> I somewhat agree in the sense that for consistency, we should either
>> move zone management commands to the DRV_OUT range OR move report_zones
>> out of this special range and just next to the zone management
>> operations. I like the latter option better, and I would love to see the
>> block layer do the same at some point. It feels backwards that
>> report_zones get special treatment all over the place.
>
> DRV_IN/OUT is purely a Linux concept.  It doesn't make any sense for
> a wire protocol.

Ok 👍

BR Andreas

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Christoph Hellwig]

On Tue, Jul 11, 2023 at 11:02:15AM +0200, Andreas Hindborg (Samsung) wrote:
> 
> Christoph Hellwig <hch@infradead.org> writes:
> 
> > On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:
> >> Yet most on-the-wire protocols for actual hardware does support this
> >> some way or another.
> >
> > Supports what?  Passthrough?  No.
> 
> Both SCSI and NVMe has command identifier ranges reserved for vendor
> specific commands. I would assume that one use of these is to implement
> passthrough channels to a device for testing out new interfaces. Just
> guessing though.

Vendor specific commands is an entirely different concept from Linux
passthrough requests.

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Andreas Hindborg (Samsung)]

Christoph Hellwig <hch@infradead.org> writes:

> On Tue, Jul 11, 2023 at 11:02:15AM +0200, Andreas Hindborg (Samsung) wrote:
>> 
>> Christoph Hellwig <hch@infradead.org> writes:
>> 
>> > On Tue, Jul 11, 2023 at 08:23:40AM +0200, Andreas Hindborg (Samsung) wrote:
>> >> Yet most on-the-wire protocols for actual hardware does support this
>> >> some way or another.
>> >
>> > Supports what?  Passthrough?  No.
>> 
>> Both SCSI and NVMe has command identifier ranges reserved for vendor
>> specific commands. I would assume that one use of these is to implement
>> passthrough channels to a device for testing out new interfaces. Just
>> guessing though.
>
> Vendor specific commands is an entirely different concept from Linux
> passthrough requests.

And yet they are somewhat similar, in the sense that they allow the user
of a protocol to express semantics that is not captured in the
established protocol. Uring command passthrough -> request passthrough
-> vendor specific commands. They sort of map well in terms of what they
allow the user to achieve. Or did I misunderstand something completely?

Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Christoph Hellwig]

On Tue, Jul 11, 2023 at 12:15:18PM +0200, Andreas Hindborg (Samsung) wrote:
> And yet they are somewhat similar, in the sense that they allow the user
> of a protocol to express semantics that is not captured in the
> established protocol. Uring command passthrough -> request passthrough
> -> vendor specific commands. They sort of map well in terms of what they
> allow the user to achieve. Or did I misunderstand something completely?

Well, there is a relationship, but it's one way.

Vendor specific command are basically always going to be used through
a passthrough interface, because they aren't standardized.

But most commands used through a passthrough interface are normal
standardized commands, just either used in a way not supported by
the normal Linux interface or just in creative ways.

[PATCH v6 2/3] ublk: add helper to check if device supports user copy

[Andreas Hindborg]

From: Andreas Hindborg <a.hindborg@samsung.com>

This will be used by ublk zoned storage support.

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
---
 drivers/block/ublk_drv.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 1c823750c95a..8d271901efac 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -185,6 +185,11 @@ struct ublk_params_header {
 	__u32	types;
 };
 
+static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
+{
+	return ub->dev_info.flags & UBLK_F_USER_COPY;
+}
+
 static inline void __ublk_complete_rq(struct request *req);
 static void ublk_complete_rq(struct kref *ref);
 
@@ -2037,7 +2042,7 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 		UBLK_F_URING_CMD_COMP_IN_TASK;
 
 	/* GET_DATA isn't needed any more with USER_COPY */
-	if (ub->dev_info.flags & UBLK_F_USER_COPY)
+	if (ublk_dev_is_user_copy(ub))
 		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
 
 	/* We are not ready to support zero copy */
-- 
2.41.0

Re: [PATCH v6 2/3] ublk: add helper to check if device supports user copy

[Damien Le Moal]

On 7/6/23 22:09, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> This will be used by ublk zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v6 2/3] ublk: add helper to check if device supports user copy

[Ming Lei]

On Thu, Jul 06, 2023 at 03:09:29PM +0200, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> This will be used by ublk zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>

Reviewed-by: Ming Lei <ming.lei@redhat.com>

Thanks,
Ming

[PATCH v6 3/3] ublk: enable zoned storage support

[Andreas Hindborg]

From: Andreas Hindborg <a.hindborg@samsung.com>

Add zoned storage support to ublk: report_zones and operations:
 - REQ_OP_ZONE_OPEN
 - REQ_OP_ZONE_CLOSE
 - REQ_OP_ZONE_FINISH
 - REQ_OP_ZONE_RESET
 - REQ_OP_ZONE_APPEND

The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
communicate ALBA back to the kernel. Therefore ublk must be used with the
user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
available. Without this feature, ublk will not allow zoned storage support.

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
---
 drivers/block/Kconfig         |   4 +
 drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
 include/uapi/linux/ublk_cmd.h |  30 +++
 3 files changed, 363 insertions(+), 12 deletions(-)

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 5b9d4aaebb81..3f7bedae8511 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -373,6 +373,7 @@ config BLK_DEV_RBD
 config BLK_DEV_UBLK
 	tristate "Userspace block driver (Experimental)"
 	select IO_URING
+	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
 	help
 	  io_uring based userspace block driver. Together with ublk server, ublk
 	  has been working well, but interface with userspace or command data
@@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
 	  suggested to enable N if your application(ublk server) switches to
 	  ioctl command encoding.
 
+config BLK_DEV_UBLK_ZONED
+	bool
+
 source "drivers/block/rnbd/Kconfig"
 
 endif # BLK_DEV
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 8d271901efac..a5adcfc976a5 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -56,22 +56,28 @@
 		| UBLK_F_USER_RECOVERY_REISSUE \
 		| UBLK_F_UNPRIVILEGED_DEV \
 		| UBLK_F_CMD_IOCTL_ENCODE \
-		| UBLK_F_USER_COPY)
+		| UBLK_F_USER_COPY \
+		| UBLK_F_ZONED)
 
 /* All UBLK_PARAM_TYPE_* should be included here */
-#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
-		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
+#define UBLK_PARAM_TYPE_ALL                                \
+	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
+	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
 
 struct ublk_rq_data {
 	struct llist_node node;
 
 	struct kref ref;
+	__u32 operation;
+	__u64 sector;
+	__u32 nr_sectors;
 };
 
 struct ublk_uring_cmd_pdu {
 	struct ublk_queue *ubq;
 };
 
+
 /*
  * io command is active: sqe cmd is received, and its cqe isn't done
  *
@@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
  */
 #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
 
+/*
+ * Set when IO is Zone Append
+ */
+#define UBLK_IO_FLAG_ZONE_APPEND 0x10
+
 struct ublk_io {
 	/* userspace buffer address from io cmd */
 	__u64	addr;
@@ -184,6 +195,31 @@ struct ublk_params_header {
 	__u32	len;
 	__u32	types;
 };
+static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
+{
+	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
+}
+
+static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
+{
+	return ub->dev_info.flags & UBLK_F_ZONED;
+}
+
+static int ublk_set_nr_zones(struct ublk_device *ub);
+static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
+static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
+static int ublk_revalidate_disk_zones(struct ublk_device *ub);
+
+#ifndef CONFIG_BLK_DEV_UBLK_ZONED
+
+#define ublk_report_zones (NULL)
+
+#else
+
+static int ublk_report_zones(struct gendisk *disk, sector_t sector,
+		      unsigned int nr_zones, report_zones_cb cb, void *data);
+
+#endif
 
 static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
 {
@@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
 		UBLK_TAG_BITS_MASK;
 }
 
-static void ublk_dev_param_basic_apply(struct ublk_device *ub)
+static int ublk_dev_param_basic_apply(struct ublk_device *ub)
 {
 	struct request_queue *q = ub->ub_disk->queue;
 	const struct ublk_param_basic *p = &ub->params.basic;
@@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
 		set_disk_ro(ub->ub_disk, true);
 
 	set_capacity(ub->ub_disk, p->dev_sectors);
+
+	if (ublk_dev_is_zoned(ub))
+		return ublk_set_nr_zones(ub);
+
+	return 0;
 }
 
 static void ublk_dev_param_discard_apply(struct ublk_device *ub)
@@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
 
 		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
 			return -EINVAL;
+
+		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
+			return -EINVAL;
 	} else
 		return -EINVAL;
 
@@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
 	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
 		return -EINVAL;
 
-	return 0;
+	return ublk_dev_param_zoned_validate(ub);
 }
 
 static int ublk_apply_params(struct ublk_device *ub)
 {
+	int ret;
+
 	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
 		return -EINVAL;
 
-	ublk_dev_param_basic_apply(ub);
+	ret = ublk_dev_param_basic_apply(ub);
+	if (ret)
+		return ret;
 
 	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
 		ublk_dev_param_discard_apply(ub);
 
+	if (ublk_dev_params_zoned(ub))
+		return ublk_dev_param_zoned_apply(ub);
+
 	return 0;
 }
 
@@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
 	.owner =	THIS_MODULE,
 	.open =		ublk_open,
 	.free_disk =	ublk_free_disk,
+	.report_zones =	ublk_report_zones,
 };
 
 #define UBLK_MAX_PIN_PAGES	32
@@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
 
 static inline bool ublk_need_unmap_req(const struct request *req)
 {
-	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
+	return ublk_rq_has_data(req) &&
+	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
 }
 
 static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
@@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
 {
 	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
 	struct ublk_io *io = &ubq->ios[req->tag];
+	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
 	u32 ublk_op;
 
 	switch (req_op(req)) {
@@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
 	case REQ_OP_WRITE_ZEROES:
 		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
 		break;
+	case REQ_OP_ZONE_OPEN:
+		ublk_op = UBLK_IO_OP_ZONE_OPEN;
+		break;
+	case REQ_OP_ZONE_CLOSE:
+		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
+		break;
+	case REQ_OP_ZONE_FINISH:
+		ublk_op = UBLK_IO_OP_ZONE_FINISH;
+		break;
+	case REQ_OP_ZONE_RESET:
+		ublk_op = UBLK_IO_OP_ZONE_RESET;
+		break;
+	case REQ_OP_DRV_IN:
+		ublk_op = pdu->operation;
+		switch (ublk_op) {
+		case UBLK_IO_OP_REPORT_ZONES:
+			iod->op_flags = ublk_op | ublk_req_build_flags(req);
+			iod->nr_sectors = pdu->nr_sectors;
+			iod->start_sector = pdu->sector;
+			return BLK_STS_OK;
+		default:
+			return BLK_STS_IOERR;
+		}
+	case REQ_OP_ZONE_APPEND:
+		ublk_op = UBLK_IO_OP_ZONE_APPEND;
+		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
+		break;
+	case REQ_OP_ZONE_RESET_ALL:
+	case REQ_OP_DRV_OUT:
+		/* We do not support reset_all and drv_out */
+		fallthrough;
 	default:
 		return BLK_STS_IOERR;
 	}
@@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
 	 *
 	 * Both the two needn't unmap.
 	 */
-	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
+	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
+	    req_op(req) != REQ_OP_DRV_IN)
 		goto exit;
 
 	/* for READ request, writing data in iod->addr to rq buffers */
@@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
 	/* find the io request and complete */
 	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
 
+	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
+		req->__sector = ub_cmd->addr;
+		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
+	}
+
 	if (req && likely(!blk_should_fake_timeout(req->q)))
 		ublk_put_req_ref(ubq, req);
 }
@@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
 		goto out;
 
-	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
+	if (ublk_support_user_copy(ubq) &&
+	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
 		int ubuf_dir)
 {
 	/* copy ubuf to request pages */
-	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
+	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
+	    ubuf_dir == ITER_SOURCE)
 		return true;
 
 	/* copy request pages to ubuf */
-	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
+	if ((req_op(req) == REQ_OP_WRITE ||
+	     req_op(req) == REQ_OP_ZONE_APPEND) &&
+	    ubuf_dir == ITER_DEST)
 		return true;
 
 	return false;
@@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
 	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
 		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
 
-	get_device(&ub->cdev_dev);
 	ub->dev_info.state = UBLK_S_DEV_LIVE;
+	ret = ublk_revalidate_disk_zones(ub);
+	if (ret)
+		goto out_put_disk;
+
+	get_device(&ub->cdev_dev);
 	ret = add_disk(disk);
 	if (ret) {
 		/*
@@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 	if (ublk_dev_is_user_copy(ub))
 		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
 
+	/* Zoned storage support requires user copy feature */
+	if (ublk_dev_is_zoned(ub) &&
+	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
+		ret = -EINVAL;
+		goto out_free_dev_number;
+	}
+
 	/* We are not ready to support zero copy */
 	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
 
@@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
 
 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
 MODULE_LICENSE("GPL");
+
+#ifdef CONFIG_BLK_DEV_UBLK_ZONED
+
+static int get_nr_zones(const struct ublk_device *ub)
+{
+	const struct ublk_param_basic *p = &ub->params.basic;
+
+	if (!p->chunk_sectors)
+		return 0;
+
+	/* Zone size is a power of 2 */
+	return p->dev_sectors >> ilog2(p->chunk_sectors);
+}
+
+static int ublk_set_nr_zones(struct ublk_device *ub)
+{
+	ub->ub_disk->nr_zones = get_nr_zones(ub);
+	if (!ub->ub_disk->nr_zones)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ublk_revalidate_disk_zones(struct ublk_device *ub)
+{
+	if (ublk_dev_is_zoned(ub))
+		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
+
+	return 0;
+}
+
+static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
+{
+	const struct ublk_param_zoned *p = &ub->params.zoned;
+	int nr_zones;
+
+	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
+		return -EINVAL;
+
+	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
+		return -EINVAL;
+
+	if (!ublk_dev_params_zoned(ub))
+		return 0;
+
+	if (!p->max_zone_append_sectors)
+		return -EINVAL;
+
+	nr_zones = get_nr_zones(ub);
+
+	if (p->max_active_zones > nr_zones)
+		return -EINVAL;
+
+	if (p->max_open_zones > nr_zones)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+	const struct ublk_param_zoned *p = &ub->params.zoned;
+
+	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
+	blk_queue_required_elevator_features(ub->ub_disk->queue,
+					     ELEVATOR_F_ZBD_SEQ_WRITE);
+	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
+	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
+	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
+
+	return 0;
+}
+
+/* Based on virtblk_alloc_report_buffer */
+static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
+				      unsigned int nr_zones, size_t *buflen)
+{
+	struct request_queue *q = ublk->ub_disk->queue;
+	size_t bufsize;
+	void *buf;
+
+	nr_zones = min_t(unsigned int, nr_zones,
+			 ublk->ub_disk->nr_zones);
+
+	bufsize = nr_zones * sizeof(struct blk_zone);
+	bufsize =
+		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
+	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
+
+	while (bufsize >= sizeof(struct blk_zone)) {
+		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
+		if (buf) {
+			*buflen = bufsize;
+			return buf;
+		}
+		bufsize >>= 1;
+	}
+
+	*buflen = 0;
+	return NULL;
+}
+
+static int ublk_report_zones(struct gendisk *disk, sector_t sector,
+		      unsigned int nr_zones, report_zones_cb cb, void *data)
+{
+	struct ublk_device *ub = disk->private_data;
+	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
+	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
+	unsigned int done_zones = 0;
+	unsigned int max_zones_per_request;
+	int ret;
+	struct blk_zone *buffer;
+	size_t buffer_length;
+
+	if (!ublk_dev_is_zoned(ub))
+		return -EOPNOTSUPP;
+
+	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
+			 nr_zones);
+
+	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
+	if (!buffer)
+		return -ENOMEM;
+
+	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
+
+	while (done_zones < nr_zones) {
+		unsigned int remaining_zones = nr_zones - done_zones;
+		unsigned int zones_in_request =
+			min_t(unsigned int, remaining_zones, max_zones_per_request);
+		struct request *req;
+		struct ublk_rq_data *pdu;
+		blk_status_t status;
+
+		memset(buffer, 0, buffer_length);
+
+		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
+		if (IS_ERR(req)) {
+			ret = PTR_ERR(req);
+			goto out;
+		}
+
+		pdu = blk_mq_rq_to_pdu(req);
+		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
+		pdu->sector = sector;
+		pdu->nr_sectors = remaining_zones * zone_size_sectors;
+
+		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
+					GFP_KERNEL);
+		if (ret) {
+			blk_mq_free_request(req);
+			goto out;
+		}
+
+		status = blk_execute_rq(req, 0);
+		ret = blk_status_to_errno(status);
+		blk_mq_free_request(req);
+		if (ret)
+			goto out;
+
+		for (unsigned int i = 0; i < zones_in_request; i++) {
+			struct blk_zone *zone = buffer + i;
+
+			/* A zero length zone means no more zones in this response */
+			if (!zone->len)
+				break;
+
+			ret = cb(zone, i, data);
+			if (ret)
+				goto out;
+
+			done_zones++;
+			sector += zone_size_sectors;
+
+		}
+	}
+
+	ret = done_zones;
+
+out:
+	kvfree(buffer);
+	return ret;
+}
+
+#else
+
+static int ublk_set_nr_zones(struct ublk_device *ub)
+{
+	return 0;
+}
+
+static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
+{
+	if (ublk_dev_params_zoned(ub))
+		return -EINVAL;
+	return 0;
+}
+
+static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+	if (ublk_dev_params_zoned(ub))
+		return -EINVAL;
+	return 0;
+}
+
+static int ublk_revalidate_disk_zones(struct ublk_device *ub)
+{
+	return 0;
+}
+
+#endif
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 2ebb8d5d827a..234c194f0a82 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -176,6 +176,12 @@
 /* Copy between request and user buffer by pread()/pwrite() */
 #define UBLK_F_USER_COPY	(1UL << 7)
 
+/*
+ * User space sets this flag when setting up the device to request zoned storage support. Kernel may
+ * deny the request by returning an error.
+ */
+#define UBLK_F_ZONED (1ULL << 8)
+
 /* device state */
 #define UBLK_S_DEV_DEAD	0
 #define UBLK_S_DEV_LIVE	1
@@ -235,6 +241,11 @@ struct ublksrv_ctrl_dev_info {
 #define		UBLK_IO_OP_DISCARD		3
 #define		UBLK_IO_OP_WRITE_SAME		4
 #define		UBLK_IO_OP_WRITE_ZEROES		5
+#define		UBLK_IO_OP_ZONE_OPEN		10
+#define		UBLK_IO_OP_ZONE_CLOSE		11
+#define		UBLK_IO_OP_ZONE_FINISH		12
+#define		UBLK_IO_OP_ZONE_APPEND		13
+#define		UBLK_IO_OP_ZONE_RESET		15
 /*
  * Passthrough (driver private) operation codes range between
  * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
@@ -242,6 +253,16 @@ struct ublksrv_ctrl_dev_info {
  * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
  */
 #define		__UBLK_IO_OP_DRV_IN_START	32
+/*
+ * Construct a zone report. The report request is carried in `struct
+ * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
+ * and shall indicate the first zone of the report. The `nr_sectors` shall
+ * indicate how many zones should be reported (divide by zone size to get number
+ * of zones in the report) and must be an integer multiple of the zone size. The
+ * report shall be delivered as a `struct blk_zone` array. To report fewer zones
+ * than requested, zero the last entry of the returned array.
+ */
+#define		UBLK_IO_OP_REPORT_ZONES		__UBLK_IO_OP_DRV_IN_START
 #define		__UBLK_IO_OP_DRV_IN_END		96
 #define		__UBLK_IO_OP_DRV_OUT_START	__UBLK_IO_OP_DRV_IN_END
 #define		__UBLK_IO_OP_DRV_OUT_END	160
@@ -341,6 +362,13 @@ struct ublk_param_devt {
 	__u32   disk_minor;
 };
 
+struct ublk_param_zoned {
+	__u32	max_open_zones;
+	__u32	max_active_zones;
+	__u32	max_zone_append_sectors;
+	__u8	reserved[20];
+};
+
 struct ublk_params {
 	/*
 	 * Total length of parameters, userspace has to set 'len' for both
@@ -352,11 +380,13 @@ struct ublk_params {
 #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
 #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
 #define UBLK_PARAM_TYPE_DEVT            (1 << 2)
+#define UBLK_PARAM_TYPE_ZONED           (1 << 3)
 	__u32	types;			/* types of parameter included */
 
 	struct ublk_param_basic		basic;
 	struct ublk_param_discard	discard;
 	struct ublk_param_devt		devt;
+	struct ublk_param_zoned	zoned;
 };
 
 #endif
-- 
2.41.0

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Damien Le Moal]

On 7/6/23 22:09, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> Add zoned storage support to ublk: report_zones and operations:
>  - REQ_OP_ZONE_OPEN
>  - REQ_OP_ZONE_CLOSE
>  - REQ_OP_ZONE_FINISH
>  - REQ_OP_ZONE_RESET
>  - REQ_OP_ZONE_APPEND
> 
> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
> communicate ALBA back to the kernel. Therefore ublk must be used with the
> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
> available. Without this feature, ublk will not allow zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> ---
>  drivers/block/Kconfig         |   4 +
>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
>  include/uapi/linux/ublk_cmd.h |  30 +++
>  3 files changed, 363 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index 5b9d4aaebb81..3f7bedae8511 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>  config BLK_DEV_UBLK
>  	tristate "Userspace block driver (Experimental)"
>  	select IO_URING
> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED

You are not adding a new file anymore. So I do not see the point of
this. You can directly use "#if[n]def CONFIG_BLK_DEV_ZONED".

>  	help
>  	  io_uring based userspace block driver. Together with ublk server, ublk
>  	  has been working well, but interface with userspace or command data
> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>  	  suggested to enable N if your application(ublk server) switches to
>  	  ioctl command encoding.
>  
> +config BLK_DEV_UBLK_ZONED
> +	bool

See above. Not needed.

> +
>  source "drivers/block/rnbd/Kconfig"
>  
>  endif # BLK_DEV
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 8d271901efac..a5adcfc976a5 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -56,22 +56,28 @@
>  		| UBLK_F_USER_RECOVERY_REISSUE \
>  		| UBLK_F_UNPRIVILEGED_DEV \
>  		| UBLK_F_CMD_IOCTL_ENCODE \
> -		| UBLK_F_USER_COPY)
> +		| UBLK_F_USER_COPY \
> +		| UBLK_F_ZONED)
>  
>  /* All UBLK_PARAM_TYPE_* should be included here */
> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
> +#define UBLK_PARAM_TYPE_ALL                                \
> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
>  
>  struct ublk_rq_data {
>  	struct llist_node node;
>  
>  	struct kref ref;
> +	__u32 operation;
> +	__u64 sector;
> +	__u32 nr_sectors;
>  };
>  
>  struct ublk_uring_cmd_pdu {
>  	struct ublk_queue *ubq;
>  };
>  
> +
>  /*
>   * io command is active: sqe cmd is received, and its cqe isn't done
>   *
> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
>   */
>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>  
> +/*
> + * Set when IO is Zone Append
> + */
> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
> +
>  struct ublk_io {
>  	/* userspace buffer address from io cmd */
>  	__u64	addr;
> @@ -184,6 +195,31 @@ struct ublk_params_header {
>  	__u32	len;
>  	__u32	types;
>  };

A blank line here would be nice.

> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
> +{
> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
> +}
> +
> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
> +{
> +	return ub->dev_info.flags & UBLK_F_ZONED;
> +}
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub);
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
> +
> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
> +
> +#define ublk_report_zones (NULL)
> +
> +#else
> +
> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
> +
> +#endif
>  
>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>  {
> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>  		UBLK_TAG_BITS_MASK;
>  }
>  
> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
>  {
>  	struct request_queue *q = ub->ub_disk->queue;
>  	const struct ublk_param_basic *p = &ub->params.basic;
> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>  		set_disk_ro(ub->ub_disk, true);
>  
>  	set_capacity(ub->ub_disk, p->dev_sectors);
> +
> +	if (ublk_dev_is_zoned(ub))
> +		return ublk_set_nr_zones(ub);
> +
> +	return 0;
>  }
>  
>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
>  
>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
>  			return -EINVAL;
> +
> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
> +			return -EINVAL;
>  	} else
>  		return -EINVAL;
>  
> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>  		return -EINVAL;
>  
> -	return 0;
> +	return ublk_dev_param_zoned_validate(ub);
>  }
>  
>  static int ublk_apply_params(struct ublk_device *ub)
>  {
> +	int ret;
> +
>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
>  		return -EINVAL;
>  
> -	ublk_dev_param_basic_apply(ub);
> +	ret = ublk_dev_param_basic_apply(ub);
> +	if (ret)
> +		return ret;
>  
>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>  		ublk_dev_param_discard_apply(ub);
>  
> +	if (ublk_dev_params_zoned(ub))
> +		return ublk_dev_param_zoned_apply(ub);
> +
>  	return 0;
>  }
>  
> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
>  	.owner =	THIS_MODULE,
>  	.open =		ublk_open,
>  	.free_disk =	ublk_free_disk,
> +	.report_zones =	ublk_report_zones,
>  };
>  
>  #define UBLK_MAX_PIN_PAGES	32
> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
>  
>  static inline bool ublk_need_unmap_req(const struct request *req)
>  {
> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
> +	return ublk_rq_has_data(req) &&
> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
>  }
>  
>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>  {
>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
>  	struct ublk_io *io = &ubq->ios[req->tag];
> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
>  	u32 ublk_op;
>  
>  	switch (req_op(req)) {
> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>  	case REQ_OP_WRITE_ZEROES:
>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
>  		break;
> +	case REQ_OP_ZONE_OPEN:
> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
> +		break;
> +	case REQ_OP_ZONE_CLOSE:
> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
> +		break;
> +	case REQ_OP_ZONE_FINISH:
> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
> +		break;
> +	case REQ_OP_ZONE_RESET:
> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
> +		break;
> +	case REQ_OP_DRV_IN:
> +		ublk_op = pdu->operation;
> +		switch (ublk_op) {
> +		case UBLK_IO_OP_REPORT_ZONES:
> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
> +			iod->nr_sectors = pdu->nr_sectors;
> +			iod->start_sector = pdu->sector;
> +			return BLK_STS_OK;
> +		default:
> +			return BLK_STS_IOERR;
> +		}
> +	case REQ_OP_ZONE_APPEND:
> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
> +		break;
> +	case REQ_OP_ZONE_RESET_ALL:
> +	case REQ_OP_DRV_OUT:
> +		/* We do not support reset_all and drv_out */
> +		fallthrough;

It would be nice to check that zone operations are attempted only on
zoned drives. Something like:

	if (!ublk_dev_is_zoned(ub) &&
	    (op_is_zone_mgmt(op) || op == REQ_OP_ZONE_APPEND))
		return -EIO;

before the switch-case maybe ?

>  	default:
>  		return BLK_STS_IOERR;
>  	}
> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
>  	 *
>  	 * Both the two needn't unmap.
>  	 */
> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
> +	    req_op(req) != REQ_OP_DRV_IN)
>  		goto exit;
>  
>  	/* for READ request, writing data in iod->addr to rq buffers */
> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
>  	/* find the io request and complete */
>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>  
> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
> +		req->__sector = ub_cmd->addr;
> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
> +	}
> +
>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>  		ublk_put_req_ref(ubq, req);
>  }
> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>  		goto out;
>  
> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
> +	if (ublk_support_user_copy(ubq) &&
> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>  		int ubuf_dir)
>  {
>  	/* copy ubuf to request pages */
> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
> +	    ubuf_dir == ITER_SOURCE)
>  		return true;
>  
>  	/* copy request pages to ubuf */
> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
> +	if ((req_op(req) == REQ_OP_WRITE ||
> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
> +	    ubuf_dir == ITER_DEST)
>  		return true;
>  
>  	return false;
> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>  
> -	get_device(&ub->cdev_dev);

Why move this ? Isn't it better to do the revalidate while holding a ref
on the device to avoid racies with remove ?

>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
> +	ret = ublk_revalidate_disk_zones(ub);
> +	if (ret)
> +		goto out_put_disk;

No need to clear the LIVE flag ?

> +
> +	get_device(&ub->cdev_dev);
>  	ret = add_disk(disk);
>  	if (ret) {
>  		/*
> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>  	if (ublk_dev_is_user_copy(ub))
>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>  
> +	/* Zoned storage support requires user copy feature */
> +	if (ublk_dev_is_zoned(ub) &&
> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {

See top comment. Use CONFIG_BLK_DEV_ZONED directly.

> +		ret = -EINVAL;
> +		goto out_free_dev_number;
> +	}
> +
>  	/* We are not ready to support zero copy */
>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
>  
> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>  
>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
>  MODULE_LICENSE("GPL");
> +
> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED

Why put these at the end ? Code after the MODULE_XXX() macros is rather
unusual. If you move all this at the top, you can likely avoid the
forward declarations as well.

> +
> +static int get_nr_zones(const struct ublk_device *ub)

ublk_get_nr_zones() ?

> +{
> +	const struct ublk_param_basic *p = &ub->params.basic;
> +
> +	if (!p->chunk_sectors)
> +		return 0;
> +
> +	/* Zone size is a power of 2 */
> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
> +}
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub)
> +{
> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
> +	if (!ub->ub_disk->nr_zones)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
> +{
> +	if (ublk_dev_is_zoned(ub))

Nit: This if could be moved to the caller site.

> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
> +
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +	int nr_zones;
> +
> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +
> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +
> +	if (!ublk_dev_params_zoned(ub))
> +		return 0;
> +
> +	if (!p->max_zone_append_sectors)
> +		return -EINVAL;
> +
> +	nr_zones = get_nr_zones(ub);
> +
> +	if (p->max_active_zones > nr_zones)
> +		return -EINVAL;
> +
> +	if (p->max_open_zones > nr_zones)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +
> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
> +
> +	return 0;

Make the function void if there is no error return.

> +}
> +
> +/* Based on virtblk_alloc_report_buffer */
> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
> +				      unsigned int nr_zones, size_t *buflen)
> +{
> +	struct request_queue *q = ublk->ub_disk->queue;
> +	size_t bufsize;
> +	void *buf;
> +
> +	nr_zones = min_t(unsigned int, nr_zones,
> +			 ublk->ub_disk->nr_zones);
> +
> +	bufsize = nr_zones * sizeof(struct blk_zone);
> +	bufsize =
> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
> +
> +	while (bufsize >= sizeof(struct blk_zone)) {
> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
> +		if (buf) {
> +			*buflen = bufsize;
> +			return buf;
> +		}
> +		bufsize >>= 1;
> +	}
> +
> +	*buflen = 0;
> +	return NULL;
> +}
> +
> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
> +{
> +	struct ublk_device *ub = disk->private_data;
> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
> +	unsigned int done_zones = 0;
> +	unsigned int max_zones_per_request;
> +	int ret;
> +	struct blk_zone *buffer;
> +	size_t buffer_length;
> +
> +	if (!ublk_dev_is_zoned(ub))
> +		return -EOPNOTSUPP;

See comment above. This shoud be checked when the command is received,
together with all other zoned operations.

> +
> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
> +			 nr_zones);
> +
> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
> +
> +	while (done_zones < nr_zones) {
> +		unsigned int remaining_zones = nr_zones - done_zones;
> +		unsigned int zones_in_request =
> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
> +		struct request *req;
> +		struct ublk_rq_data *pdu;
> +		blk_status_t status;
> +
> +		memset(buffer, 0, buffer_length);
> +
> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
> +		if (IS_ERR(req)) {
> +			ret = PTR_ERR(req);

Nit: if this happens while you already got some zones in the report
(that is, not on the first iteration), then you could return these zones
instead of an error. But not a big deal.

> +			goto out;
> +		}
> +
> +		pdu = blk_mq_rq_to_pdu(req);
> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
> +		pdu->sector = sector;
> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
> +
> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
> +					GFP_KERNEL);
> +		if (ret) {
> +			blk_mq_free_request(req);

Same here.

> +			goto out;
> +		}
> +
> +		status = blk_execute_rq(req, 0);
> +		ret = blk_status_to_errno(status);
> +		blk_mq_free_request(req);
> +		if (ret)
> +			goto out;
> +
> +		for (unsigned int i = 0; i < zones_in_request; i++) {
> +			struct blk_zone *zone = buffer + i;
> +
> +			/* A zero length zone means no more zones in this response */
> +			if (!zone->len)
> +				break;
> +
> +			ret = cb(zone, i, data);
> +			if (ret)
> +				goto out;
> +
> +			done_zones++;
> +			sector += zone_size_sectors;
> +
> +		}
> +	}
> +
> +	ret = done_zones;
> +
> +out:
> +	kvfree(buffer);
> +	return ret;
> +}
> +
> +#else
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub)
> +{
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> +{
> +	if (ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
> +{
> +	if (ublk_dev_params_zoned(ub))
> +		return -EINVAL;

The caller site calls this only if ublk_dev_params_zoned() is true. So
this should be an unconditional return -ENOTSUPP I think.

> +	return 0;
> +}
> +
> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
> +{
> +	return 0;
> +}
> +
> +#endif
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 2ebb8d5d827a..234c194f0a82 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -176,6 +176,12 @@
>  /* Copy between request and user buffer by pread()/pwrite() */
>  #define UBLK_F_USER_COPY	(1UL << 7)
>  
> +/*
> + * User space sets this flag when setting up the device to request zoned storage support. Kernel may
> + * deny the request by returning an error.
> + */
> +#define UBLK_F_ZONED (1ULL << 8)
> +
>  /* device state */
>  #define UBLK_S_DEV_DEAD	0
>  #define UBLK_S_DEV_LIVE	1
> @@ -235,6 +241,11 @@ struct ublksrv_ctrl_dev_info {
>  #define		UBLK_IO_OP_DISCARD		3
>  #define		UBLK_IO_OP_WRITE_SAME		4
>  #define		UBLK_IO_OP_WRITE_ZEROES		5
> +#define		UBLK_IO_OP_ZONE_OPEN		10
> +#define		UBLK_IO_OP_ZONE_CLOSE		11
> +#define		UBLK_IO_OP_ZONE_FINISH		12
> +#define		UBLK_IO_OP_ZONE_APPEND		13
> +#define		UBLK_IO_OP_ZONE_RESET		15
>  /*
>   * Passthrough (driver private) operation codes range between
>   * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
> @@ -242,6 +253,16 @@ struct ublksrv_ctrl_dev_info {
>   * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
>   */
>  #define		__UBLK_IO_OP_DRV_IN_START	32
> +/*
> + * Construct a zone report. The report request is carried in `struct
> + * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
> + * and shall indicate the first zone of the report. The `nr_sectors` shall
> + * indicate how many zones should be reported (divide by zone size to get number
> + * of zones in the report) and must be an integer multiple of the zone size. The
> + * report shall be delivered as a `struct blk_zone` array. To report fewer zones
> + * than requested, zero the last entry of the returned array.
> + */
> +#define		UBLK_IO_OP_REPORT_ZONES		__UBLK_IO_OP_DRV_IN_START
>  #define		__UBLK_IO_OP_DRV_IN_END		96
>  #define		__UBLK_IO_OP_DRV_OUT_START	__UBLK_IO_OP_DRV_IN_END
>  #define		__UBLK_IO_OP_DRV_OUT_END	160
> @@ -341,6 +362,13 @@ struct ublk_param_devt {
>  	__u32   disk_minor;
>  };
>  
> +struct ublk_param_zoned {
> +	__u32	max_open_zones;
> +	__u32	max_active_zones;
> +	__u32	max_zone_append_sectors;
> +	__u8	reserved[20];
> +};
> +
>  struct ublk_params {
>  	/*
>  	 * Total length of parameters, userspace has to set 'len' for both
> @@ -352,11 +380,13 @@ struct ublk_params {
>  #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
>  #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
>  #define UBLK_PARAM_TYPE_DEVT            (1 << 2)
> +#define UBLK_PARAM_TYPE_ZONED           (1 << 3)
>  	__u32	types;			/* types of parameter included */
>  
>  	struct ublk_param_basic		basic;
>  	struct ublk_param_discard	discard;
>  	struct ublk_param_devt		devt;
> +	struct ublk_param_zoned	zoned;
>  };
>  
>  #endif

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Andreas Hindborg (Samsung)]

Damien Le Moal <dlemoal@kernel.org> writes:

> On 7/6/23 22:09, Andreas Hindborg wrote:
>> From: Andreas Hindborg <a.hindborg@samsung.com>
>> 
>> Add zoned storage support to ublk: report_zones and operations:
>>  - REQ_OP_ZONE_OPEN
>>  - REQ_OP_ZONE_CLOSE
>>  - REQ_OP_ZONE_FINISH
>>  - REQ_OP_ZONE_RESET
>>  - REQ_OP_ZONE_APPEND
>> 
>> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
>> communicate ALBA back to the kernel. Therefore ublk must be used with the
>> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
>> available. Without this feature, ublk will not allow zoned storage support.
>> 
>> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>> ---
>>  drivers/block/Kconfig         |   4 +
>>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
>>  include/uapi/linux/ublk_cmd.h |  30 +++
>>  3 files changed, 363 insertions(+), 12 deletions(-)
>> 
>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> index 5b9d4aaebb81..3f7bedae8511 100644
>> --- a/drivers/block/Kconfig
>> +++ b/drivers/block/Kconfig
>> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>>  config BLK_DEV_UBLK
>>  	tristate "Userspace block driver (Experimental)"
>>  	select IO_URING
>> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
>
> You are not adding a new file anymore. So I do not see the point of
> this. You can directly use "#if[n]def CONFIG_BLK_DEV_ZONED".
>
>>  	help
>>  	  io_uring based userspace block driver. Together with ublk server, ublk
>>  	  has been working well, but interface with userspace or command data
>> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>>  	  suggested to enable N if your application(ublk server) switches to
>>  	  ioctl command encoding.
>>  
>> +config BLK_DEV_UBLK_ZONED
>> +	bool
>
> See above. Not needed.
>

Agreed 👍

>> +
>>  source "drivers/block/rnbd/Kconfig"
>>  
>>  endif # BLK_DEV
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index 8d271901efac..a5adcfc976a5 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -56,22 +56,28 @@
>>  		| UBLK_F_USER_RECOVERY_REISSUE \
>>  		| UBLK_F_UNPRIVILEGED_DEV \
>>  		| UBLK_F_CMD_IOCTL_ENCODE \
>> -		| UBLK_F_USER_COPY)
>> +		| UBLK_F_USER_COPY \
>> +		| UBLK_F_ZONED)
>>  
>>  /* All UBLK_PARAM_TYPE_* should be included here */
>> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
>> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
>> +#define UBLK_PARAM_TYPE_ALL                                \
>> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
>> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
>>  
>>  struct ublk_rq_data {
>>  	struct llist_node node;
>>  
>>  	struct kref ref;
>> +	__u32 operation;
>> +	__u64 sector;
>> +	__u32 nr_sectors;
>>  };
>>  
>>  struct ublk_uring_cmd_pdu {
>>  	struct ublk_queue *ubq;
>>  };
>>  
>> +
>>  /*
>>   * io command is active: sqe cmd is received, and its cqe isn't done
>>   *
>> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
>>   */
>>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>>  
>> +/*
>> + * Set when IO is Zone Append
>> + */
>> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
>> +
>>  struct ublk_io {
>>  	/* userspace buffer address from io cmd */
>>  	__u64	addr;
>> @@ -184,6 +195,31 @@ struct ublk_params_header {
>>  	__u32	len;
>>  	__u32	types;
>>  };
>
> A blank line here would be nice.
>
>> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
>> +{
>> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
>> +}
>> +
>> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
>> +{
>> +	return ub->dev_info.flags & UBLK_F_ZONED;
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
>> +
>> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
>> +
>> +#define ublk_report_zones (NULL)
>> +
>> +#else
>> +
>> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
>> +
>> +#endif
>>  
>>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>>  {
>> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>>  		UBLK_TAG_BITS_MASK;
>>  }
>>  
>> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
>>  {
>>  	struct request_queue *q = ub->ub_disk->queue;
>>  	const struct ublk_param_basic *p = &ub->params.basic;
>> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>>  		set_disk_ro(ub->ub_disk, true);
>>  
>>  	set_capacity(ub->ub_disk, p->dev_sectors);
>> +
>> +	if (ublk_dev_is_zoned(ub))
>> +		return ublk_set_nr_zones(ub);
>> +
>> +	return 0;
>>  }
>>  
>>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
>>  
>>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
>>  			return -EINVAL;
>> +
>> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
>> +			return -EINVAL;
>>  	} else
>>  		return -EINVAL;
>>  
>> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>>  		return -EINVAL;
>>  
>> -	return 0;
>> +	return ublk_dev_param_zoned_validate(ub);
>>  }
>>  
>>  static int ublk_apply_params(struct ublk_device *ub)
>>  {
>> +	int ret;
>> +
>>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
>>  		return -EINVAL;
>>  
>> -	ublk_dev_param_basic_apply(ub);
>> +	ret = ublk_dev_param_basic_apply(ub);
>> +	if (ret)
>> +		return ret;
>>  
>>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>>  		ublk_dev_param_discard_apply(ub);
>>  
>> +	if (ublk_dev_params_zoned(ub))
>> +		return ublk_dev_param_zoned_apply(ub);
>> +
>>  	return 0;
>>  }
>>  
>> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
>>  	.owner =	THIS_MODULE,
>>  	.open =		ublk_open,
>>  	.free_disk =	ublk_free_disk,
>> +	.report_zones =	ublk_report_zones,
>>  };
>>  
>>  #define UBLK_MAX_PIN_PAGES	32
>> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
>>  
>>  static inline bool ublk_need_unmap_req(const struct request *req)
>>  {
>> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
>> +	return ublk_rq_has_data(req) &&
>> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
>>  }
>>  
>>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
>> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>>  {
>>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
>>  	struct ublk_io *io = &ubq->ios[req->tag];
>> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
>>  	u32 ublk_op;
>>  
>>  	switch (req_op(req)) {
>> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>>  	case REQ_OP_WRITE_ZEROES:
>>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
>>  		break;
>> +	case REQ_OP_ZONE_OPEN:
>> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
>> +		break;
>> +	case REQ_OP_ZONE_CLOSE:
>> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
>> +		break;
>> +	case REQ_OP_ZONE_FINISH:
>> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
>> +		break;
>> +	case REQ_OP_ZONE_RESET:
>> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
>> +		break;
>> +	case REQ_OP_DRV_IN:
>> +		ublk_op = pdu->operation;
>> +		switch (ublk_op) {
>> +		case UBLK_IO_OP_REPORT_ZONES:
>> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
>> +			iod->nr_sectors = pdu->nr_sectors;
>> +			iod->start_sector = pdu->sector;
>> +			return BLK_STS_OK;
>> +		default:
>> +			return BLK_STS_IOERR;
>> +		}
>> +	case REQ_OP_ZONE_APPEND:
>> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
>> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
>> +		break;
>> +	case REQ_OP_ZONE_RESET_ALL:
>> +	case REQ_OP_DRV_OUT:
>> +		/* We do not support reset_all and drv_out */
>> +		fallthrough;
>
> It would be nice to check that zone operations are attempted only on
> zoned drives. Something like:
>
> 	if (!ublk_dev_is_zoned(ub) &&
> 	    (op_is_zone_mgmt(op) || op == REQ_OP_ZONE_APPEND))
> 		return -EIO;
>
> before the switch-case maybe ?

Sure 👍

>
>>  	default:
>>  		return BLK_STS_IOERR;
>>  	}
>> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
>>  	 *
>>  	 * Both the two needn't unmap.
>>  	 */
>> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
>> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
>> +	    req_op(req) != REQ_OP_DRV_IN)
>>  		goto exit;
>>  
>>  	/* for READ request, writing data in iod->addr to rq buffers */
>> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
>>  	/* find the io request and complete */
>>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>>  
>> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
>> +		req->__sector = ub_cmd->addr;
>> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
>> +	}
>> +
>>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>>  		ublk_put_req_ref(ubq, req);
>>  }
>> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>>  		goto out;
>>  
>> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> +	if (ublk_support_user_copy(ubq) &&
>> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>>  		ret = -EINVAL;
>>  		goto out;
>>  	}
>> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>>  		int ubuf_dir)
>>  {
>>  	/* copy ubuf to request pages */
>> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
>> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
>> +	    ubuf_dir == ITER_SOURCE)
>>  		return true;
>>  
>>  	/* copy request pages to ubuf */
>> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
>> +	if ((req_op(req) == REQ_OP_WRITE ||
>> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
>> +	    ubuf_dir == ITER_DEST)
>>  		return true;
>>  
>>  	return false;
>> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>>  
>> -	get_device(&ub->cdev_dev);
>
> Why move this ? Isn't it better to do the revalidate while holding a ref
> on the device to avoid racies with remove ?
>
>>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
>> +	ret = ublk_revalidate_disk_zones(ub);
>> +	if (ret)
>> +		goto out_put_disk;
>
> No need to clear the LIVE flag ?

Yes, will rework this a bit, thanks.

>
>> +
>> +	get_device(&ub->cdev_dev);
>>  	ret = add_disk(disk);
>>  	if (ret) {
>>  		/*
>> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>>  	if (ublk_dev_is_user_copy(ub))
>>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>>  
>> +	/* Zoned storage support requires user copy feature */
>> +	if (ublk_dev_is_zoned(ub) &&
>> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
>
> See top comment. Use CONFIG_BLK_DEV_ZONED directly.
>
>> +		ret = -EINVAL;
>> +		goto out_free_dev_number;
>> +	}
>> +
>>  	/* We are not ready to support zero copy */
>>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
>>  
>> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>>  
>>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
>>  MODULE_LICENSE("GPL");
>> +
>> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
>
> Why put these at the end ? Code after the MODULE_XXX() macros is rather
> unusual. If you move all this at the top, you can likely avoid the
> forward declarations as well.

Alright

>
>> +
>> +static int get_nr_zones(const struct ublk_device *ub)
>
> ublk_get_nr_zones() ?

Yes

>
>> +{
>> +	const struct ublk_param_basic *p = &ub->params.basic;
>> +
>> +	if (!p->chunk_sectors)
>> +		return 0;
>> +
>> +	/* Zone size is a power of 2 */
>> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
>> +	if (!ub->ub_disk->nr_zones)
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_is_zoned(ub))
>
> Nit: This if could be moved to the caller site.

Ok. `ublk_revalidate_disk_zones()` still required because
blk_revalidate_disk_zones not defined when !CONFIG_BLK_DEV_ZONED though.

>
>> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> +{
>> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> +	int nr_zones;
>> +
>> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +
>> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +
>> +	if (!ublk_dev_params_zoned(ub))
>> +		return 0;
>> +
>> +	if (!p->max_zone_append_sectors)
>> +		return -EINVAL;
>> +
>> +	nr_zones = get_nr_zones(ub);
>> +
>> +	if (p->max_active_zones > nr_zones)
>> +		return -EINVAL;
>> +
>> +	if (p->max_open_zones > nr_zones)
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> +{
>> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> +
>> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
>> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
>> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
>> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
>> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
>> +
>> +	return 0;
>
> Make the function void if there is no error return.

It needs to be non void because it does validation when !CONFIG_BLK_DEV_ZONED.

>
>> +}
>> +
>> +/* Based on virtblk_alloc_report_buffer */
>> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
>> +				      unsigned int nr_zones, size_t *buflen)
>> +{
>> +	struct request_queue *q = ublk->ub_disk->queue;
>> +	size_t bufsize;
>> +	void *buf;
>> +
>> +	nr_zones = min_t(unsigned int, nr_zones,
>> +			 ublk->ub_disk->nr_zones);
>> +
>> +	bufsize = nr_zones * sizeof(struct blk_zone);
>> +	bufsize =
>> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
>> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
>> +
>> +	while (bufsize >= sizeof(struct blk_zone)) {
>> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
>> +		if (buf) {
>> +			*buflen = bufsize;
>> +			return buf;
>> +		}
>> +		bufsize >>= 1;
>> +	}
>> +
>> +	*buflen = 0;
>> +	return NULL;
>> +}
>> +
>> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
>> +{
>> +	struct ublk_device *ub = disk->private_data;
>> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
>> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
>> +	unsigned int done_zones = 0;
>> +	unsigned int max_zones_per_request;
>> +	int ret;
>> +	struct blk_zone *buffer;
>> +	size_t buffer_length;
>> +
>> +	if (!ublk_dev_is_zoned(ub))
>> +		return -EOPNOTSUPP;
>
> See comment above. This shoud be checked when the command is received,
> together with all other zoned operations.

Ok

>
>> +
>> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
>> +			 nr_zones);
>> +
>> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
>> +	if (!buffer)
>> +		return -ENOMEM;
>> +
>> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
>> +
>> +	while (done_zones < nr_zones) {
>> +		unsigned int remaining_zones = nr_zones - done_zones;
>> +		unsigned int zones_in_request =
>> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
>> +		struct request *req;
>> +		struct ublk_rq_data *pdu;
>> +		blk_status_t status;
>> +
>> +		memset(buffer, 0, buffer_length);
>> +
>> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
>> +		if (IS_ERR(req)) {
>> +			ret = PTR_ERR(req);
>
> Nit: if this happens while you already got some zones in the report
> (that is, not on the first iteration), then you could return these zones
> instead of an error. But not a big deal.

Is it really worth the extra lines of code? I'm thinking if you hit this
you have other problems and the half zone report probably won't be of
any use.

>
>> +			goto out;
>> +		}
>> +
>> +		pdu = blk_mq_rq_to_pdu(req);
>> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
>> +		pdu->sector = sector;
>> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
>> +
>> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
>> +					GFP_KERNEL);
>> +		if (ret) {
>> +			blk_mq_free_request(req);
>
> Same here.
>
>> +			goto out;
>> +		}
>> +
>> +		status = blk_execute_rq(req, 0);
>> +		ret = blk_status_to_errno(status);
>> +		blk_mq_free_request(req);
>> +		if (ret)
>> +			goto out;
>> +
>> +		for (unsigned int i = 0; i < zones_in_request; i++) {
>> +			struct blk_zone *zone = buffer + i;
>> +
>> +			/* A zero length zone means no more zones in this response */
>> +			if (!zone->len)
>> +				break;
>> +
>> +			ret = cb(zone, i, data);
>> +			if (ret)
>> +				goto out;
>> +
>> +			done_zones++;
>> +			sector += zone_size_sectors;
>> +
>> +		}
>> +	}
>> +
>> +	ret = done_zones;
>> +
>> +out:
>> +	kvfree(buffer);
>> +	return ret;
>> +}
>> +
>> +#else
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>
> The caller site calls this only if ublk_dev_params_zoned() is true. So
> this should be an unconditional return -ENOTSUPP I think.

Yes

>
>> +	return 0;
>> +}
>> +
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
>> +{
>> +	return 0;
>> +}
>> +
>> +#endif
>> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
>> index 2ebb8d5d827a..234c194f0a82 100644
>> --- a/include/uapi/linux/ublk_cmd.h
>> +++ b/include/uapi/linux/ublk_cmd.h
>> @@ -176,6 +176,12 @@
>>  /* Copy between request and user buffer by pread()/pwrite() */
>>  #define UBLK_F_USER_COPY	(1UL << 7)
>>  
>> +/*
>> + * User space sets this flag when setting up the device to request zoned storage support. Kernel may
>> + * deny the request by returning an error.
>> + */
>> +#define UBLK_F_ZONED (1ULL << 8)
>> +
>>  /* device state */
>>  #define UBLK_S_DEV_DEAD	0
>>  #define UBLK_S_DEV_LIVE	1
>> @@ -235,6 +241,11 @@ struct ublksrv_ctrl_dev_info {
>>  #define		UBLK_IO_OP_DISCARD		3
>>  #define		UBLK_IO_OP_WRITE_SAME		4
>>  #define		UBLK_IO_OP_WRITE_ZEROES		5
>> +#define		UBLK_IO_OP_ZONE_OPEN		10
>> +#define		UBLK_IO_OP_ZONE_CLOSE		11
>> +#define		UBLK_IO_OP_ZONE_FINISH		12
>> +#define		UBLK_IO_OP_ZONE_APPEND		13
>> +#define		UBLK_IO_OP_ZONE_RESET		15
>>  /*
>>   * Passthrough (driver private) operation codes range between
>>   * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
>> @@ -242,6 +253,16 @@ struct ublksrv_ctrl_dev_info {
>>   * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
>>   */
>>  #define		__UBLK_IO_OP_DRV_IN_START	32
>> +/*
>> + * Construct a zone report. The report request is carried in `struct
>> + * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
>> + * and shall indicate the first zone of the report. The `nr_sectors` shall
>> + * indicate how many zones should be reported (divide by zone size to get number
>> + * of zones in the report) and must be an integer multiple of the zone size. The
>> + * report shall be delivered as a `struct blk_zone` array. To report fewer zones
>> + * than requested, zero the last entry of the returned array.
>> + */
>> +#define		UBLK_IO_OP_REPORT_ZONES		__UBLK_IO_OP_DRV_IN_START
>>  #define		__UBLK_IO_OP_DRV_IN_END		96
>>  #define		__UBLK_IO_OP_DRV_OUT_START	__UBLK_IO_OP_DRV_IN_END
>>  #define		__UBLK_IO_OP_DRV_OUT_END	160
>> @@ -341,6 +362,13 @@ struct ublk_param_devt {
>>  	__u32   disk_minor;
>>  };
>>  
>> +struct ublk_param_zoned {
>> +	__u32	max_open_zones;
>> +	__u32	max_active_zones;
>> +	__u32	max_zone_append_sectors;
>> +	__u8	reserved[20];
>> +};
>> +
>>  struct ublk_params {
>>  	/*
>>  	 * Total length of parameters, userspace has to set 'len' for both
>> @@ -352,11 +380,13 @@ struct ublk_params {
>>  #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
>>  #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
>>  #define UBLK_PARAM_TYPE_DEVT            (1 << 2)
>> +#define UBLK_PARAM_TYPE_ZONED           (1 << 3)
>>  	__u32	types;			/* types of parameter included */
>>  
>>  	struct ublk_param_basic		basic;
>>  	struct ublk_param_discard	discard;
>>  	struct ublk_param_devt		devt;
>> +	struct ublk_param_zoned	zoned;
>>  };
>>  
>>  #endif

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Ming Lei]

On Thu, Jul 06, 2023 at 03:09:30PM +0200, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> Add zoned storage support to ublk: report_zones and operations:
>  - REQ_OP_ZONE_OPEN
>  - REQ_OP_ZONE_CLOSE
>  - REQ_OP_ZONE_FINISH
>  - REQ_OP_ZONE_RESET
>  - REQ_OP_ZONE_APPEND
> 
> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
> communicate ALBA back to the kernel. Therefore ublk must be used with the
> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
> available. Without this feature, ublk will not allow zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> ---
>  drivers/block/Kconfig         |   4 +
>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
>  include/uapi/linux/ublk_cmd.h |  30 +++
>  3 files changed, 363 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index 5b9d4aaebb81..3f7bedae8511 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>  config BLK_DEV_UBLK
>  	tristate "Userspace block driver (Experimental)"
>  	select IO_URING
> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
>  	help
>  	  io_uring based userspace block driver. Together with ublk server, ublk
>  	  has been working well, but interface with userspace or command data
> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>  	  suggested to enable N if your application(ublk server) switches to
>  	  ioctl command encoding.
>  
> +config BLK_DEV_UBLK_ZONED
> +	bool
> +
>  source "drivers/block/rnbd/Kconfig"
>  
>  endif # BLK_DEV
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 8d271901efac..a5adcfc976a5 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -56,22 +56,28 @@
>  		| UBLK_F_USER_RECOVERY_REISSUE \
>  		| UBLK_F_UNPRIVILEGED_DEV \
>  		| UBLK_F_CMD_IOCTL_ENCODE \
> -		| UBLK_F_USER_COPY)
> +		| UBLK_F_USER_COPY \
> +		| UBLK_F_ZONED)
>  
>  /* All UBLK_PARAM_TYPE_* should be included here */
> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
> +#define UBLK_PARAM_TYPE_ALL                                \
> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
>  
>  struct ublk_rq_data {
>  	struct llist_node node;
>  
>  	struct kref ref;
> +	__u32 operation;
> +	__u64 sector;
> +	__u32 nr_sectors;
>  };

Please put "operation" and "nr_sectors" together, then holes
can be avoided.

>  
>  struct ublk_uring_cmd_pdu {
>  	struct ublk_queue *ubq;
>  };
>  
> +

?

>  /*
>   * io command is active: sqe cmd is received, and its cqe isn't done
>   *
> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
>   */
>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>  
> +/*
> + * Set when IO is Zone Append
> + */
> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
> +
>  struct ublk_io {
>  	/* userspace buffer address from io cmd */
>  	__u64	addr;
> @@ -184,6 +195,31 @@ struct ublk_params_header {
>  	__u32	len;
>  	__u32	types;
>  };
> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
> +{
> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
> +}
> +
> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
> +{
> +	return ub->dev_info.flags & UBLK_F_ZONED;
> +}
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub);
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
> +
> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
> +
> +#define ublk_report_zones (NULL)
> +
> +#else
> +
> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
> +
> +#endif

Please merge the following "#ifdef CONFIG_BLK_DEV_UBLK_ZONED" with the
above one, then you can avoid the above declarations. Meantime, we don't
add code after MODULE_LICENSE().

>  
>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>  {
> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>  		UBLK_TAG_BITS_MASK;
>  }
>  
> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
>  {
>  	struct request_queue *q = ub->ub_disk->queue;
>  	const struct ublk_param_basic *p = &ub->params.basic;
> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>  		set_disk_ro(ub->ub_disk, true);
>  
>  	set_capacity(ub->ub_disk, p->dev_sectors);
> +
> +	if (ublk_dev_is_zoned(ub))
> +		return ublk_set_nr_zones(ub);
> +

The above change can be moved into ublk_dev_param_zoned_apply() which
is always done after ublk_dev_param_basic_apply(). 

> +	return 0;
>  }
>  
>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
>  
>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
>  			return -EINVAL;
> +
> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
> +			return -EINVAL;
>  	} else
>  		return -EINVAL;
>  
> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>  		return -EINVAL;
>  
> -	return 0;
> +	return ublk_dev_param_zoned_validate(ub);

Please follow current style of:

	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
		return ublk_dev_param_zoned_validate(ub);

Then you can avoid lots of check on ublk_dev_params_zoned().

>  }
>  
>  static int ublk_apply_params(struct ublk_device *ub)
>  {
> +	int ret;
> +
>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
>  		return -EINVAL;
>  
> -	ublk_dev_param_basic_apply(ub);
> +	ret = ublk_dev_param_basic_apply(ub);
> +	if (ret)
> +		return ret;
>  
>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>  		ublk_dev_param_discard_apply(ub);
>  
> +	if (ublk_dev_params_zoned(ub))
> +		return ublk_dev_param_zoned_apply(ub);
> +
>  	return 0;
>  }
>  
> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
>  	.owner =	THIS_MODULE,
>  	.open =		ublk_open,
>  	.free_disk =	ublk_free_disk,
> +	.report_zones =	ublk_report_zones,
>  };
>  
>  #define UBLK_MAX_PIN_PAGES	32
> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
>  
>  static inline bool ublk_need_unmap_req(const struct request *req)
>  {
> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
> +	return ublk_rq_has_data(req) &&
> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
>  }
>  
>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>  {
>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
>  	struct ublk_io *io = &ubq->ios[req->tag];
> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
>  	u32 ublk_op;
>  
>  	switch (req_op(req)) {
> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>  	case REQ_OP_WRITE_ZEROES:
>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
>  		break;
> +	case REQ_OP_ZONE_OPEN:
> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
> +		break;
> +	case REQ_OP_ZONE_CLOSE:
> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
> +		break;
> +	case REQ_OP_ZONE_FINISH:
> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
> +		break;
> +	case REQ_OP_ZONE_RESET:
> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
> +		break;
> +	case REQ_OP_DRV_IN:
> +		ublk_op = pdu->operation;
> +		switch (ublk_op) {
> +		case UBLK_IO_OP_REPORT_ZONES:
> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
> +			iod->nr_sectors = pdu->nr_sectors;
> +			iod->start_sector = pdu->sector;
> +			return BLK_STS_OK;
> +		default:
> +			return BLK_STS_IOERR;
> +		}
> +	case REQ_OP_ZONE_APPEND:
> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
> +		break;
> +	case REQ_OP_ZONE_RESET_ALL:

BLK_STS_NOTSUPP should be returned, since in future we may support it,
and userspace need to know what is wrong.

> +	case REQ_OP_DRV_OUT:
> +		/* We do not support reset_all and drv_out */
> +		fallthrough;
>  	default:
>  		return BLK_STS_IOERR;
>  	}
> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
>  	 *
>  	 * Both the two needn't unmap.
>  	 */
> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
> +	    req_op(req) != REQ_OP_DRV_IN)
>  		goto exit;
>  
>  	/* for READ request, writing data in iod->addr to rq buffers */
> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
>  	/* find the io request and complete */
>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>  
> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
> +		req->__sector = ub_cmd->addr;
> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
> +	}
> +
>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>  		ublk_put_req_ref(ubq, req);
>  }
> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>  		goto out;
>  
> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
> +	if (ublk_support_user_copy(ubq) &&
> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>  		ret = -EINVAL;
>  		goto out;
>  	}
> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>  		int ubuf_dir)
>  {
>  	/* copy ubuf to request pages */
> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
> +	    ubuf_dir == ITER_SOURCE)
>  		return true;
>  
>  	/* copy request pages to ubuf */
> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
> +	if ((req_op(req) == REQ_OP_WRITE ||
> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
> +	    ubuf_dir == ITER_DEST)
>  		return true;
>  
>  	return false;
> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>  
> -	get_device(&ub->cdev_dev);
>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
> +	ret = ublk_revalidate_disk_zones(ub);
> +	if (ret)
> +		goto out_put_disk;
> +
> +	get_device(&ub->cdev_dev);
>  	ret = add_disk(disk);
>  	if (ret) {
>  		/*
> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>  	if (ublk_dev_is_user_copy(ub))
>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>  
> +	/* Zoned storage support requires user copy feature */
> +	if (ublk_dev_is_zoned(ub) &&
> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
> +		ret = -EINVAL;
> +		goto out_free_dev_number;
> +	}
> +
>  	/* We are not ready to support zero copy */
>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
>  
> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>  
>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
>  MODULE_LICENSE("GPL");
> +
> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
> +
> +static int get_nr_zones(const struct ublk_device *ub)
> +{
> +	const struct ublk_param_basic *p = &ub->params.basic;
> +
> +	if (!p->chunk_sectors)
> +		return 0;

There isn't zoned device if the above check fails, so no
need to check it.

> +
> +	/* Zone size is a power of 2 */
> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
> +}
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub)
> +{
> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
> +	if (!ub->ub_disk->nr_zones)
> +		return -EINVAL;

Is nr_zones one must for zoned?

> +
> +	return 0;
> +}
> +
> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
> +{
> +	if (ublk_dev_is_zoned(ub))
> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
> +
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +	int nr_zones;
> +
> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +
> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +
> +	if (!ublk_dev_params_zoned(ub))
> +		return 0;

The above can be simplified as single check if we follow current
validate/apply code style:

	if (!ublk_dev_is_zoned(ub))
		return -EINVAL;

> +
> +	if (!p->max_zone_append_sectors)
> +		return -EINVAL;
> +
> +	nr_zones = get_nr_zones(ub);
> +
> +	if (p->max_active_zones > nr_zones)
> +		return -EINVAL;
> +
> +	if (p->max_open_zones > nr_zones)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +
> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
> +
> +	return 0;
> +}
> +
> +/* Based on virtblk_alloc_report_buffer */
> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
> +				      unsigned int nr_zones, size_t *buflen)
> +{
> +	struct request_queue *q = ublk->ub_disk->queue;
> +	size_t bufsize;
> +	void *buf;
> +
> +	nr_zones = min_t(unsigned int, nr_zones,
> +			 ublk->ub_disk->nr_zones);
> +
> +	bufsize = nr_zones * sizeof(struct blk_zone);
> +	bufsize =
> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
> +
> +	while (bufsize >= sizeof(struct blk_zone)) {
> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
> +		if (buf) {
> +			*buflen = bufsize;
> +			return buf;
> +		}
> +		bufsize >>= 1;
> +	}
> +
> +	*buflen = 0;
> +	return NULL;
> +}
> +
> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
> +{
> +	struct ublk_device *ub = disk->private_data;
> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
> +	unsigned int done_zones = 0;
> +	unsigned int max_zones_per_request;
> +	int ret;
> +	struct blk_zone *buffer;
> +	size_t buffer_length;
> +
> +	if (!ublk_dev_is_zoned(ub))
> +		return -EOPNOTSUPP;
> +
> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
> +			 nr_zones);
> +
> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
> +
> +	while (done_zones < nr_zones) {
> +		unsigned int remaining_zones = nr_zones - done_zones;
> +		unsigned int zones_in_request =
> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
> +		struct request *req;
> +		struct ublk_rq_data *pdu;
> +		blk_status_t status;
> +
> +		memset(buffer, 0, buffer_length);
> +
> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
> +		if (IS_ERR(req)) {
> +			ret = PTR_ERR(req);
> +			goto out;
> +		}
> +
> +		pdu = blk_mq_rq_to_pdu(req);
> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
> +		pdu->sector = sector;
> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
> +
> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
> +					GFP_KERNEL);
> +		if (ret) {
> +			blk_mq_free_request(req);
> +			goto out;
> +		}
> +
> +		status = blk_execute_rq(req, 0);
> +		ret = blk_status_to_errno(status);
> +		blk_mq_free_request(req);
> +		if (ret)
> +			goto out;
> +
> +		for (unsigned int i = 0; i < zones_in_request; i++) {
> +			struct blk_zone *zone = buffer + i;
> +
> +			/* A zero length zone means no more zones in this response */
> +			if (!zone->len)
> +				break;
> +
> +			ret = cb(zone, i, data);
> +			if (ret)
> +				goto out;
> +
> +			done_zones++;
> +			sector += zone_size_sectors;
> +
> +		}
> +	}
> +
> +	ret = done_zones;
> +
> +out:
> +	kvfree(buffer);
> +	return ret;
> +}
> +
> +#else
> +
> +static int ublk_set_nr_zones(struct ublk_device *ub)
> +{
> +	return 0;
> +}
> +
> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> +{
> +	if (ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +	return 0;

Please move the check outside by following current code style, then:

		return -EINVAL;

> +}
> +
> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
> +{
> +	if (ublk_dev_params_zoned(ub))
> +		return -EINVAL;
> +	return 0;

It is enough to change 

	return -EINVAL;

directly.


Thanks, 
Ming

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Andreas Hindborg (Samsung)]

Ming Lei <ming.lei@redhat.com> writes:

> On Thu, Jul 06, 2023 at 03:09:30PM +0200, Andreas Hindborg wrote:
>> From: Andreas Hindborg <a.hindborg@samsung.com>
>> 
>> Add zoned storage support to ublk: report_zones and operations:
>>  - REQ_OP_ZONE_OPEN
>>  - REQ_OP_ZONE_CLOSE
>>  - REQ_OP_ZONE_FINISH
>>  - REQ_OP_ZONE_RESET
>>  - REQ_OP_ZONE_APPEND
>> 
>> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
>> communicate ALBA back to the kernel. Therefore ublk must be used with the
>> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
>> available. Without this feature, ublk will not allow zoned storage support.
>> 
>> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>> ---
>>  drivers/block/Kconfig         |   4 +
>>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
>>  include/uapi/linux/ublk_cmd.h |  30 +++
>>  3 files changed, 363 insertions(+), 12 deletions(-)
>> 
>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> index 5b9d4aaebb81..3f7bedae8511 100644
>> --- a/drivers/block/Kconfig
>> +++ b/drivers/block/Kconfig
>> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>>  config BLK_DEV_UBLK
>>  	tristate "Userspace block driver (Experimental)"
>>  	select IO_URING
>> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
>>  	help
>>  	  io_uring based userspace block driver. Together with ublk server, ublk
>>  	  has been working well, but interface with userspace or command data
>> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>>  	  suggested to enable N if your application(ublk server) switches to
>>  	  ioctl command encoding.
>>  
>> +config BLK_DEV_UBLK_ZONED
>> +	bool
>> +
>>  source "drivers/block/rnbd/Kconfig"
>>  
>>  endif # BLK_DEV
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index 8d271901efac..a5adcfc976a5 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -56,22 +56,28 @@
>>  		| UBLK_F_USER_RECOVERY_REISSUE \
>>  		| UBLK_F_UNPRIVILEGED_DEV \
>>  		| UBLK_F_CMD_IOCTL_ENCODE \
>> -		| UBLK_F_USER_COPY)
>> +		| UBLK_F_USER_COPY \
>> +		| UBLK_F_ZONED)
>>  
>>  /* All UBLK_PARAM_TYPE_* should be included here */
>> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
>> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
>> +#define UBLK_PARAM_TYPE_ALL                                \
>> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
>> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
>>  
>>  struct ublk_rq_data {
>>  	struct llist_node node;
>>  
>>  	struct kref ref;
>> +	__u32 operation;
>> +	__u64 sector;
>> +	__u32 nr_sectors;
>>  };
>
> Please put "operation" and "nr_sectors" together, then holes
> can be avoided.

Got it 👍

>
>>  
>>  struct ublk_uring_cmd_pdu {
>>  	struct ublk_queue *ubq;
>>  };
>>  
>> +
>
> ?

Sorry.

>
>>  /*
>>   * io command is active: sqe cmd is received, and its cqe isn't done
>>   *
>> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
>>   */
>>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>>  
>> +/*
>> + * Set when IO is Zone Append
>> + */
>> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
>> +
>>  struct ublk_io {
>>  	/* userspace buffer address from io cmd */
>>  	__u64	addr;
>> @@ -184,6 +195,31 @@ struct ublk_params_header {
>>  	__u32	len;
>>  	__u32	types;
>>  };
>> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
>> +{
>> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
>> +}
>> +
>> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
>> +{
>> +	return ub->dev_info.flags & UBLK_F_ZONED;
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
>> +
>> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
>> +
>> +#define ublk_report_zones (NULL)
>> +
>> +#else
>> +
>> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
>> +
>> +#endif
>
> Please merge the following "#ifdef CONFIG_BLK_DEV_UBLK_ZONED" with the
> above one, then you can avoid the above declarations. Meantime, we don't
> add code after MODULE_LICENSE().

Ok 👍

>
>>  
>>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>>  {
>> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>>  		UBLK_TAG_BITS_MASK;
>>  }
>>  
>> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
>>  {
>>  	struct request_queue *q = ub->ub_disk->queue;
>>  	const struct ublk_param_basic *p = &ub->params.basic;
>> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>>  		set_disk_ro(ub->ub_disk, true);
>>  
>>  	set_capacity(ub->ub_disk, p->dev_sectors);
>> +
>> +	if (ublk_dev_is_zoned(ub))
>> +		return ublk_set_nr_zones(ub);
>> +
>
> The above change can be moved into ublk_dev_param_zoned_apply() which
> is always done after ublk_dev_param_basic_apply(). 

Ok

>
>> +	return 0;
>>  }
>>  
>>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
>>  
>>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
>>  			return -EINVAL;
>> +
>> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
>> +			return -EINVAL;
>>  	} else
>>  		return -EINVAL;
>>  
>> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>>  		return -EINVAL;
>>  
>> -	return 0;
>> +	return ublk_dev_param_zoned_validate(ub);
>
> Please follow current style of:
>
> 	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
> 		return ublk_dev_param_zoned_validate(ub);
>
> Then you can avoid lots of check on ublk_dev_params_zoned().

Ok, but then I need


	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
		return -EINVAL;

here to check if user is forgetting zoned parameters for zoned ublk dev.
Or do you want to drop this check?

>
>>  }
>>  
>>  static int ublk_apply_params(struct ublk_device *ub)
>>  {
>> +	int ret;
>> +
>>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
>>  		return -EINVAL;
>>  
>> -	ublk_dev_param_basic_apply(ub);
>> +	ret = ublk_dev_param_basic_apply(ub);
>> +	if (ret)
>> +		return ret;
>>  
>>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>>  		ublk_dev_param_discard_apply(ub);
>>  
>> +	if (ublk_dev_params_zoned(ub))
>> +		return ublk_dev_param_zoned_apply(ub);
>> +
>>  	return 0;
>>  }
>>  
>> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
>>  	.owner =	THIS_MODULE,
>>  	.open =		ublk_open,
>>  	.free_disk =	ublk_free_disk,
>> +	.report_zones =	ublk_report_zones,
>>  };
>>  
>>  #define UBLK_MAX_PIN_PAGES	32
>> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
>>  
>>  static inline bool ublk_need_unmap_req(const struct request *req)
>>  {
>> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
>> +	return ublk_rq_has_data(req) &&
>> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
>>  }
>>  
>>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
>> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>>  {
>>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
>>  	struct ublk_io *io = &ubq->ios[req->tag];
>> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
>>  	u32 ublk_op;
>>  
>>  	switch (req_op(req)) {
>> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>>  	case REQ_OP_WRITE_ZEROES:
>>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
>>  		break;
>> +	case REQ_OP_ZONE_OPEN:
>> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
>> +		break;
>> +	case REQ_OP_ZONE_CLOSE:
>> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
>> +		break;
>> +	case REQ_OP_ZONE_FINISH:
>> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
>> +		break;
>> +	case REQ_OP_ZONE_RESET:
>> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
>> +		break;
>> +	case REQ_OP_DRV_IN:
>> +		ublk_op = pdu->operation;
>> +		switch (ublk_op) {
>> +		case UBLK_IO_OP_REPORT_ZONES:
>> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
>> +			iod->nr_sectors = pdu->nr_sectors;
>> +			iod->start_sector = pdu->sector;
>> +			return BLK_STS_OK;
>> +		default:
>> +			return BLK_STS_IOERR;
>> +		}
>> +	case REQ_OP_ZONE_APPEND:
>> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
>> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
>> +		break;
>> +	case REQ_OP_ZONE_RESET_ALL:
>
> BLK_STS_NOTSUPP should be returned, since in future we may support it,
> and userspace need to know what is wrong.

Ok

>
>> +	case REQ_OP_DRV_OUT:
>> +		/* We do not support reset_all and drv_out */
>> +		fallthrough;
>>  	default:
>>  		return BLK_STS_IOERR;
>>  	}
>> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
>>  	 *
>>  	 * Both the two needn't unmap.
>>  	 */
>> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
>> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
>> +	    req_op(req) != REQ_OP_DRV_IN)
>>  		goto exit;
>>  
>>  	/* for READ request, writing data in iod->addr to rq buffers */
>> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
>>  	/* find the io request and complete */
>>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>>  
>> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
>> +		req->__sector = ub_cmd->addr;
>> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
>> +	}
>> +
>>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>>  		ublk_put_req_ref(ubq, req);
>>  }
>> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>>  		goto out;
>>  
>> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> +	if (ublk_support_user_copy(ubq) &&
>> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>>  		ret = -EINVAL;
>>  		goto out;
>>  	}
>> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>>  		int ubuf_dir)
>>  {
>>  	/* copy ubuf to request pages */
>> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
>> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
>> +	    ubuf_dir == ITER_SOURCE)
>>  		return true;
>>  
>>  	/* copy request pages to ubuf */
>> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
>> +	if ((req_op(req) == REQ_OP_WRITE ||
>> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
>> +	    ubuf_dir == ITER_DEST)
>>  		return true;
>>  
>>  	return false;
>> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>>  
>> -	get_device(&ub->cdev_dev);
>>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
>> +	ret = ublk_revalidate_disk_zones(ub);
>> +	if (ret)
>> +		goto out_put_disk;
>> +
>> +	get_device(&ub->cdev_dev);
>>  	ret = add_disk(disk);
>>  	if (ret) {
>>  		/*
>> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>>  	if (ublk_dev_is_user_copy(ub))
>>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>>  
>> +	/* Zoned storage support requires user copy feature */
>> +	if (ublk_dev_is_zoned(ub) &&
>> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
>> +		ret = -EINVAL;
>> +		goto out_free_dev_number;
>> +	}
>> +
>>  	/* We are not ready to support zero copy */
>>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
>>  
>> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>>  
>>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
>>  MODULE_LICENSE("GPL");
>> +
>> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
>> +
>> +static int get_nr_zones(const struct ublk_device *ub)
>> +{
>> +	const struct ublk_param_basic *p = &ub->params.basic;
>> +
>> +	if (!p->chunk_sectors)
>> +		return 0;
>
> There isn't zoned device if the above check fails, so no
> need to check it.

Ok, but this is called from `ublk_dev_param_zoned_validate()` to
validate user sets params correct. Should we not report error to user
space during parameter validation if user space sets chunk_sectors to
zero for zoned device?

>
>> +
>> +	/* Zone size is a power of 2 */
>> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
>> +	if (!ub->ub_disk->nr_zones)
>> +		return -EINVAL;
>
> Is nr_zones one must for zoned?

Zero zones for a zoned storage device is not allowed, as far as I am
aware. Am I mistaken?

>
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_is_zoned(ub))
>> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> +{
>> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> +	int nr_zones;
>> +
>> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +
>> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +
>> +	if (!ublk_dev_params_zoned(ub))
>> +		return 0;
>
> The above can be simplified as single check if we follow current
> validate/apply code style:
>
> 	if (!ublk_dev_is_zoned(ub))
> 		return -EINVAL;

If we do that we will not be able to check if user space sets the
`UBLK_F_ZONED` flag without setting zoned parameters. Should I validate
that at call site or drop the check?

>> +
>> +	if (!p->max_zone_append_sectors)
>> +		return -EINVAL;
>> +
>> +	nr_zones = get_nr_zones(ub);
>> +
>> +	if (p->max_active_zones > nr_zones)
>> +		return -EINVAL;
>> +
>> +	if (p->max_open_zones > nr_zones)
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> +{
>> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> +
>> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
>> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
>> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
>> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
>> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
>> +
>> +	return 0;
>> +}
>> +
>> +/* Based on virtblk_alloc_report_buffer */
>> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
>> +				      unsigned int nr_zones, size_t *buflen)
>> +{
>> +	struct request_queue *q = ublk->ub_disk->queue;
>> +	size_t bufsize;
>> +	void *buf;
>> +
>> +	nr_zones = min_t(unsigned int, nr_zones,
>> +			 ublk->ub_disk->nr_zones);
>> +
>> +	bufsize = nr_zones * sizeof(struct blk_zone);
>> +	bufsize =
>> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
>> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
>> +
>> +	while (bufsize >= sizeof(struct blk_zone)) {
>> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
>> +		if (buf) {
>> +			*buflen = bufsize;
>> +			return buf;
>> +		}
>> +		bufsize >>= 1;
>> +	}
>> +
>> +	*buflen = 0;
>> +	return NULL;
>> +}
>> +
>> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
>> +{
>> +	struct ublk_device *ub = disk->private_data;
>> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
>> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
>> +	unsigned int done_zones = 0;
>> +	unsigned int max_zones_per_request;
>> +	int ret;
>> +	struct blk_zone *buffer;
>> +	size_t buffer_length;
>> +
>> +	if (!ublk_dev_is_zoned(ub))
>> +		return -EOPNOTSUPP;
>> +
>> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
>> +			 nr_zones);
>> +
>> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
>> +	if (!buffer)
>> +		return -ENOMEM;
>> +
>> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
>> +
>> +	while (done_zones < nr_zones) {
>> +		unsigned int remaining_zones = nr_zones - done_zones;
>> +		unsigned int zones_in_request =
>> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
>> +		struct request *req;
>> +		struct ublk_rq_data *pdu;
>> +		blk_status_t status;
>> +
>> +		memset(buffer, 0, buffer_length);
>> +
>> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
>> +		if (IS_ERR(req)) {
>> +			ret = PTR_ERR(req);
>> +			goto out;
>> +		}
>> +
>> +		pdu = blk_mq_rq_to_pdu(req);
>> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
>> +		pdu->sector = sector;
>> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
>> +
>> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
>> +					GFP_KERNEL);
>> +		if (ret) {
>> +			blk_mq_free_request(req);
>> +			goto out;
>> +		}
>> +
>> +		status = blk_execute_rq(req, 0);
>> +		ret = blk_status_to_errno(status);
>> +		blk_mq_free_request(req);
>> +		if (ret)
>> +			goto out;
>> +
>> +		for (unsigned int i = 0; i < zones_in_request; i++) {
>> +			struct blk_zone *zone = buffer + i;
>> +
>> +			/* A zero length zone means no more zones in this response */
>> +			if (!zone->len)
>> +				break;
>> +
>> +			ret = cb(zone, i, data);
>> +			if (ret)
>> +				goto out;
>> +
>> +			done_zones++;
>> +			sector += zone_size_sectors;
>> +
>> +		}
>> +	}
>> +
>> +	ret = done_zones;
>> +
>> +out:
>> +	kvfree(buffer);
>> +	return ret;
>> +}
>> +
>> +#else
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> +	return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +	return 0;
>
> Please move the check outside by following current code style, then:
>
> 		return -EINVAL;
>

Ok, but then we move the check for user applying zoned params to
non-zoned device when CONFIG_BLK_DEV_ZONED to call site?

>> +}
>> +
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> +{
>> +	if (ublk_dev_params_zoned(ub))
>> +		return -EINVAL;
>> +	return 0;
>
> It is enough to change 
>
> 	return -EINVAL;
>
> directly.

Ok

Best regards,
Andreas

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Ming Lei]

On Fri, Jul 07, 2023 at 05:04:41PM +0200, Andreas Hindborg (Samsung) wrote:
> 
> Ming Lei <ming.lei@redhat.com> writes:
> 
> > On Thu, Jul 06, 2023 at 03:09:30PM +0200, Andreas Hindborg wrote:
> >> From: Andreas Hindborg <a.hindborg@samsung.com>
> >> 
> >> Add zoned storage support to ublk: report_zones and operations:
> >>  - REQ_OP_ZONE_OPEN
> >>  - REQ_OP_ZONE_CLOSE
> >>  - REQ_OP_ZONE_FINISH
> >>  - REQ_OP_ZONE_RESET
> >>  - REQ_OP_ZONE_APPEND
> >> 
> >> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
> >> communicate ALBA back to the kernel. Therefore ublk must be used with the
> >> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
> >> available. Without this feature, ublk will not allow zoned storage support.
> >> 
> >> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> >> ---
> >>  drivers/block/Kconfig         |   4 +
> >>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
> >>  include/uapi/linux/ublk_cmd.h |  30 +++
> >>  3 files changed, 363 insertions(+), 12 deletions(-)
> >> 
> >> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> >> index 5b9d4aaebb81..3f7bedae8511 100644
> >> --- a/drivers/block/Kconfig
> >> +++ b/drivers/block/Kconfig
> >> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
> >>  config BLK_DEV_UBLK
> >>  	tristate "Userspace block driver (Experimental)"
> >>  	select IO_URING
> >> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
> >>  	help
> >>  	  io_uring based userspace block driver. Together with ublk server, ublk
> >>  	  has been working well, but interface with userspace or command data
> >> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
> >>  	  suggested to enable N if your application(ublk server) switches to
> >>  	  ioctl command encoding.
> >>  
> >> +config BLK_DEV_UBLK_ZONED
> >> +	bool
> >> +
> >>  source "drivers/block/rnbd/Kconfig"
> >>  
> >>  endif # BLK_DEV
> >> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> >> index 8d271901efac..a5adcfc976a5 100644
> >> --- a/drivers/block/ublk_drv.c
> >> +++ b/drivers/block/ublk_drv.c
> >> @@ -56,22 +56,28 @@
> >>  		| UBLK_F_USER_RECOVERY_REISSUE \
> >>  		| UBLK_F_UNPRIVILEGED_DEV \
> >>  		| UBLK_F_CMD_IOCTL_ENCODE \
> >> -		| UBLK_F_USER_COPY)
> >> +		| UBLK_F_USER_COPY \
> >> +		| UBLK_F_ZONED)
> >>  
> >>  /* All UBLK_PARAM_TYPE_* should be included here */
> >> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
> >> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
> >> +#define UBLK_PARAM_TYPE_ALL                                \
> >> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
> >> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
> >>  
> >>  struct ublk_rq_data {
> >>  	struct llist_node node;
> >>  
> >>  	struct kref ref;
> >> +	__u32 operation;
> >> +	__u64 sector;
> >> +	__u32 nr_sectors;
> >>  };
> >
> > Please put "operation" and "nr_sectors" together, then holes
> > can be avoided.
> 
> Got it 👍
> 
> >
> >>  
> >>  struct ublk_uring_cmd_pdu {
> >>  	struct ublk_queue *ubq;
> >>  };
> >>  
> >> +
> >
> > ?
> 
> Sorry.
> 
> >
> >>  /*
> >>   * io command is active: sqe cmd is received, and its cqe isn't done
> >>   *
> >> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
> >>   */
> >>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
> >>  
> >> +/*
> >> + * Set when IO is Zone Append
> >> + */
> >> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
> >> +
> >>  struct ublk_io {
> >>  	/* userspace buffer address from io cmd */
> >>  	__u64	addr;
> >> @@ -184,6 +195,31 @@ struct ublk_params_header {
> >>  	__u32	len;
> >>  	__u32	types;
> >>  };
> >> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
> >> +{
> >> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
> >> +}
> >> +
> >> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
> >> +{
> >> +	return ub->dev_info.flags & UBLK_F_ZONED;
> >> +}
> >> +
> >> +static int ublk_set_nr_zones(struct ublk_device *ub);
> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
> >> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
> >> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
> >> +
> >> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
> >> +
> >> +#define ublk_report_zones (NULL)
> >> +
> >> +#else
> >> +
> >> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> >> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
> >> +
> >> +#endif
> >
> > Please merge the following "#ifdef CONFIG_BLK_DEV_UBLK_ZONED" with the
> > above one, then you can avoid the above declarations. Meantime, we don't
> > add code after MODULE_LICENSE().
> 
> Ok 👍
> 
> >
> >>  
> >>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
> >>  {
> >> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
> >>  		UBLK_TAG_BITS_MASK;
> >>  }
> >>  
> >> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> >> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
> >>  {
> >>  	struct request_queue *q = ub->ub_disk->queue;
> >>  	const struct ublk_param_basic *p = &ub->params.basic;
> >> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
> >>  		set_disk_ro(ub->ub_disk, true);
> >>  
> >>  	set_capacity(ub->ub_disk, p->dev_sectors);
> >> +
> >> +	if (ublk_dev_is_zoned(ub))
> >> +		return ublk_set_nr_zones(ub);
> >> +
> >
> > The above change can be moved into ublk_dev_param_zoned_apply() which
> > is always done after ublk_dev_param_basic_apply(). 
> 
> Ok
> 
> >
> >> +	return 0;
> >>  }
> >>  
> >>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
> >> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
> >>  
> >>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
> >>  			return -EINVAL;
> >> +
> >> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
> >> +			return -EINVAL;
> >>  	} else
> >>  		return -EINVAL;
> >>  
> >> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
> >>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
> >>  		return -EINVAL;
> >>  
> >> -	return 0;
> >> +	return ublk_dev_param_zoned_validate(ub);
> >
> > Please follow current style of:
> >
> > 	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
> > 		return ublk_dev_param_zoned_validate(ub);
> >
> > Then you can avoid lots of check on ublk_dev_params_zoned().
> 
> Ok, but then I need
> 
> 
> 	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
> 		return -EINVAL;
> 
> here to check if user is forgetting zoned parameters for zoned ublk dev.
> Or do you want to drop this check?

OK, zoned is a bit special, then you still can do it:

 	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
 		return ublk_dev_param_zoned_validate(ub);
	else if (ublk_dev_is_zoned(ub))
		return -EINVAL;

which is more readable.

> 
> >
> >>  }
> >>  
> >>  static int ublk_apply_params(struct ublk_device *ub)
> >>  {
> >> +	int ret;
> >> +
> >>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
> >>  		return -EINVAL;
> >>  
> >> -	ublk_dev_param_basic_apply(ub);
> >> +	ret = ublk_dev_param_basic_apply(ub);
> >> +	if (ret)
> >> +		return ret;
> >>  
> >>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
> >>  		ublk_dev_param_discard_apply(ub);
> >>  
> >> +	if (ublk_dev_params_zoned(ub))
> >> +		return ublk_dev_param_zoned_apply(ub);
> >> +
> >>  	return 0;
> >>  }
> >>  
> >> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
> >>  	.owner =	THIS_MODULE,
> >>  	.open =		ublk_open,
> >>  	.free_disk =	ublk_free_disk,
> >> +	.report_zones =	ublk_report_zones,
> >>  };
> >>  
> >>  #define UBLK_MAX_PIN_PAGES	32
> >> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
> >>  
> >>  static inline bool ublk_need_unmap_req(const struct request *req)
> >>  {
> >> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
> >> +	return ublk_rq_has_data(req) &&
> >> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
> >>  }
> >>  
> >>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
> >> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
> >>  {
> >>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
> >>  	struct ublk_io *io = &ubq->ios[req->tag];
> >> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
> >>  	u32 ublk_op;
> >>  
> >>  	switch (req_op(req)) {
> >> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
> >>  	case REQ_OP_WRITE_ZEROES:
> >>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
> >>  		break;
> >> +	case REQ_OP_ZONE_OPEN:
> >> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
> >> +		break;
> >> +	case REQ_OP_ZONE_CLOSE:
> >> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
> >> +		break;
> >> +	case REQ_OP_ZONE_FINISH:
> >> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
> >> +		break;
> >> +	case REQ_OP_ZONE_RESET:
> >> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
> >> +		break;
> >> +	case REQ_OP_DRV_IN:
> >> +		ublk_op = pdu->operation;
> >> +		switch (ublk_op) {
> >> +		case UBLK_IO_OP_REPORT_ZONES:
> >> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
> >> +			iod->nr_sectors = pdu->nr_sectors;
> >> +			iod->start_sector = pdu->sector;
> >> +			return BLK_STS_OK;
> >> +		default:
> >> +			return BLK_STS_IOERR;
> >> +		}
> >> +	case REQ_OP_ZONE_APPEND:
> >> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
> >> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
> >> +		break;
> >> +	case REQ_OP_ZONE_RESET_ALL:
> >
> > BLK_STS_NOTSUPP should be returned, since in future we may support it,
> > and userspace need to know what is wrong.
> 
> Ok
> 
> >
> >> +	case REQ_OP_DRV_OUT:
> >> +		/* We do not support reset_all and drv_out */
> >> +		fallthrough;
> >>  	default:
> >>  		return BLK_STS_IOERR;
> >>  	}
> >> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
> >>  	 *
> >>  	 * Both the two needn't unmap.
> >>  	 */
> >> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
> >> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
> >> +	    req_op(req) != REQ_OP_DRV_IN)
> >>  		goto exit;
> >>  
> >>  	/* for READ request, writing data in iod->addr to rq buffers */
> >> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
> >>  	/* find the io request and complete */
> >>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
> >>  
> >> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
> >> +		req->__sector = ub_cmd->addr;
> >> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
> >> +	}
> >> +
> >>  	if (req && likely(!blk_should_fake_timeout(req->q)))
> >>  		ublk_put_req_ref(ubq, req);
> >>  }
> >> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
> >>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
> >>  		goto out;
> >>  
> >> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
> >> +	if (ublk_support_user_copy(ubq) &&
> >> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
> >>  		ret = -EINVAL;
> >>  		goto out;
> >>  	}
> >> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
> >>  		int ubuf_dir)
> >>  {
> >>  	/* copy ubuf to request pages */
> >> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
> >> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
> >> +	    ubuf_dir == ITER_SOURCE)
> >>  		return true;
> >>  
> >>  	/* copy request pages to ubuf */
> >> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
> >> +	if ((req_op(req) == REQ_OP_WRITE ||
> >> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
> >> +	    ubuf_dir == ITER_DEST)
> >>  		return true;
> >>  
> >>  	return false;
> >> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
> >>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
> >>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
> >>  
> >> -	get_device(&ub->cdev_dev);
> >>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
> >> +	ret = ublk_revalidate_disk_zones(ub);
> >> +	if (ret)
> >> +		goto out_put_disk;
> >> +
> >> +	get_device(&ub->cdev_dev);
> >>  	ret = add_disk(disk);
> >>  	if (ret) {
> >>  		/*
> >> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
> >>  	if (ublk_dev_is_user_copy(ub))
> >>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
> >>  
> >> +	/* Zoned storage support requires user copy feature */
> >> +	if (ublk_dev_is_zoned(ub) &&
> >> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
> >> +		ret = -EINVAL;
> >> +		goto out_free_dev_number;
> >> +	}
> >> +
> >>  	/* We are not ready to support zero copy */
> >>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
> >>  
> >> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
> >>  
> >>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
> >>  MODULE_LICENSE("GPL");
> >> +
> >> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
> >> +
> >> +static int get_nr_zones(const struct ublk_device *ub)
> >> +{
> >> +	const struct ublk_param_basic *p = &ub->params.basic;
> >> +
> >> +	if (!p->chunk_sectors)
> >> +		return 0;
> >
> > There isn't zoned device if the above check fails, so no
> > need to check it.
> 
> Ok, but this is called from `ublk_dev_param_zoned_validate()` to
> validate user sets params correct. Should we not report error to user
> space during parameter validation if user space sets chunk_sectors to
> zero for zoned device?

That has been covered in UBLK_PARAM_TYPE_BASIC branch of ublk_validate_params().

> 
> >
> >> +
> >> +	/* Zone size is a power of 2 */
> >> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
> >> +}
> >> +
> >> +static int ublk_set_nr_zones(struct ublk_device *ub)
> >> +{
> >> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
> >> +	if (!ub->ub_disk->nr_zones)
> >> +		return -EINVAL;
> >
> > Is nr_zones one must for zoned?
> 
> Zero zones for a zoned storage device is not allowed, as far as I am
> aware. Am I mistaken?

OK, never mind, I just didn't see such check in null zoned and virtio-blk.

> 
> >
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
> >> +{
> >> +	if (ublk_dev_is_zoned(ub))
> >> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> >> +{
> >> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> >> +	int nr_zones;
> >> +
> >> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
> >> +		return -EINVAL;
> >> +
> >> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
> >> +		return -EINVAL;
> >> +
> >> +	if (!ublk_dev_params_zoned(ub))
> >> +		return 0;
> >
> > The above can be simplified as single check if we follow current
> > validate/apply code style:
> >
> > 	if (!ublk_dev_is_zoned(ub))
> > 		return -EINVAL;
> 
> If we do that we will not be able to check if user space sets the
> `UBLK_F_ZONED` flag without setting zoned parameters. Should I validate
> that at call site or drop the check?

Please see above comment, which can be covered as:

 	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
 		return ublk_dev_param_zoned_validate(ub);
	else if (ublk_dev_is_zoned(ub))
		return -EINVAL;

> 
> >> +
> >> +	if (!p->max_zone_append_sectors)
> >> +		return -EINVAL;
> >> +
> >> +	nr_zones = get_nr_zones(ub);
> >> +
> >> +	if (p->max_active_zones > nr_zones)
> >> +		return -EINVAL;
> >> +
> >> +	if (p->max_open_zones > nr_zones)
> >> +		return -EINVAL;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
> >> +{
> >> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> >> +
> >> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
> >> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
> >> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
> >> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
> >> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
> >> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +/* Based on virtblk_alloc_report_buffer */
> >> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
> >> +				      unsigned int nr_zones, size_t *buflen)
> >> +{
> >> +	struct request_queue *q = ublk->ub_disk->queue;
> >> +	size_t bufsize;
> >> +	void *buf;
> >> +
> >> +	nr_zones = min_t(unsigned int, nr_zones,
> >> +			 ublk->ub_disk->nr_zones);
> >> +
> >> +	bufsize = nr_zones * sizeof(struct blk_zone);
> >> +	bufsize =
> >> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
> >> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
> >> +
> >> +	while (bufsize >= sizeof(struct blk_zone)) {
> >> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
> >> +		if (buf) {
> >> +			*buflen = bufsize;
> >> +			return buf;
> >> +		}
> >> +		bufsize >>= 1;
> >> +	}
> >> +
> >> +	*buflen = 0;
> >> +	return NULL;
> >> +}
> >> +
> >> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> >> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
> >> +{
> >> +	struct ublk_device *ub = disk->private_data;
> >> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
> >> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
> >> +	unsigned int done_zones = 0;
> >> +	unsigned int max_zones_per_request;
> >> +	int ret;
> >> +	struct blk_zone *buffer;
> >> +	size_t buffer_length;
> >> +
> >> +	if (!ublk_dev_is_zoned(ub))
> >> +		return -EOPNOTSUPP;
> >> +
> >> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
> >> +			 nr_zones);
> >> +
> >> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
> >> +	if (!buffer)
> >> +		return -ENOMEM;
> >> +
> >> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
> >> +
> >> +	while (done_zones < nr_zones) {
> >> +		unsigned int remaining_zones = nr_zones - done_zones;
> >> +		unsigned int zones_in_request =
> >> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
> >> +		struct request *req;
> >> +		struct ublk_rq_data *pdu;
> >> +		blk_status_t status;
> >> +
> >> +		memset(buffer, 0, buffer_length);
> >> +
> >> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
> >> +		if (IS_ERR(req)) {
> >> +			ret = PTR_ERR(req);
> >> +			goto out;
> >> +		}
> >> +
> >> +		pdu = blk_mq_rq_to_pdu(req);
> >> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
> >> +		pdu->sector = sector;
> >> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
> >> +
> >> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
> >> +					GFP_KERNEL);
> >> +		if (ret) {
> >> +			blk_mq_free_request(req);
> >> +			goto out;
> >> +		}
> >> +
> >> +		status = blk_execute_rq(req, 0);
> >> +		ret = blk_status_to_errno(status);
> >> +		blk_mq_free_request(req);
> >> +		if (ret)
> >> +			goto out;
> >> +
> >> +		for (unsigned int i = 0; i < zones_in_request; i++) {
> >> +			struct blk_zone *zone = buffer + i;
> >> +
> >> +			/* A zero length zone means no more zones in this response */
> >> +			if (!zone->len)
> >> +				break;
> >> +
> >> +			ret = cb(zone, i, data);
> >> +			if (ret)
> >> +				goto out;
> >> +
> >> +			done_zones++;
> >> +			sector += zone_size_sectors;
> >> +
> >> +		}
> >> +	}
> >> +
> >> +	ret = done_zones;
> >> +
> >> +out:
> >> +	kvfree(buffer);
> >> +	return ret;
> >> +}
> >> +
> >> +#else
> >> +
> >> +static int ublk_set_nr_zones(struct ublk_device *ub)
> >> +{
> >> +	return 0;
> >> +}
> >> +
> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
> >> +{
> >> +	if (ublk_dev_params_zoned(ub))
> >> +		return -EINVAL;
> >> +	return 0;
> >
> > Please move the check outside by following current code style, then:
> >
> > 		return -EINVAL;
> >
> 
> Ok, but then we move the check for user applying zoned params to
> non-zoned device when CONFIG_BLK_DEV_ZONED to call site?

Yes, the point is to move check in common code, then not only reduce
repeated check, but also cleaner.


Thanks, 
Ming

Re: [PATCH v6 3/3] ublk: enable zoned storage support

[Andreas Hindborg (Samsung)]

Ming Lei <ming.lei@redhat.com> writes:

> On Fri, Jul 07, 2023 at 05:04:41PM +0200, Andreas Hindborg (Samsung) wrote:
>> 
>> Ming Lei <ming.lei@redhat.com> writes:
>> 
>> > On Thu, Jul 06, 2023 at 03:09:30PM +0200, Andreas Hindborg wrote:
>> >> From: Andreas Hindborg <a.hindborg@samsung.com>
>> >> 
>> >> Add zoned storage support to ublk: report_zones and operations:
>> >>  - REQ_OP_ZONE_OPEN
>> >>  - REQ_OP_ZONE_CLOSE
>> >>  - REQ_OP_ZONE_FINISH
>> >>  - REQ_OP_ZONE_RESET
>> >>  - REQ_OP_ZONE_APPEND
>> >> 
>> >> The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
>> >> communicate ALBA back to the kernel. Therefore ublk must be used with the
>> >> user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
>> >> available. Without this feature, ublk will not allow zoned storage support.
>> >> 
>> >> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>> >> ---
>> >>  drivers/block/Kconfig         |   4 +
>> >>  drivers/block/ublk_drv.c      | 341 ++++++++++++++++++++++++++++++++--
>> >>  include/uapi/linux/ublk_cmd.h |  30 +++
>> >>  3 files changed, 363 insertions(+), 12 deletions(-)
>> >> 
>> >> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> >> index 5b9d4aaebb81..3f7bedae8511 100644
>> >> --- a/drivers/block/Kconfig
>> >> +++ b/drivers/block/Kconfig
>> >> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>> >>  config BLK_DEV_UBLK
>> >>  	tristate "Userspace block driver (Experimental)"
>> >>  	select IO_URING
>> >> +	select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
>> >>  	help
>> >>  	  io_uring based userspace block driver. Together with ublk server, ublk
>> >>  	  has been working well, but interface with userspace or command data
>> >> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>> >>  	  suggested to enable N if your application(ublk server) switches to
>> >>  	  ioctl command encoding.
>> >>  
>> >> +config BLK_DEV_UBLK_ZONED
>> >> +	bool
>> >> +
>> >>  source "drivers/block/rnbd/Kconfig"
>> >>  
>> >>  endif # BLK_DEV
>> >> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> >> index 8d271901efac..a5adcfc976a5 100644
>> >> --- a/drivers/block/ublk_drv.c
>> >> +++ b/drivers/block/ublk_drv.c
>> >> @@ -56,22 +56,28 @@
>> >>  		| UBLK_F_USER_RECOVERY_REISSUE \
>> >>  		| UBLK_F_UNPRIVILEGED_DEV \
>> >>  		| UBLK_F_CMD_IOCTL_ENCODE \
>> >> -		| UBLK_F_USER_COPY)
>> >> +		| UBLK_F_USER_COPY \
>> >> +		| UBLK_F_ZONED)
>> >>  
>> >>  /* All UBLK_PARAM_TYPE_* should be included here */
>> >> -#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
>> >> -		UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
>> >> +#define UBLK_PARAM_TYPE_ALL                                \
>> >> +	(UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
>> >> +	 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
>> >>  
>> >>  struct ublk_rq_data {
>> >>  	struct llist_node node;
>> >>  
>> >>  	struct kref ref;
>> >> +	__u32 operation;
>> >> +	__u64 sector;
>> >> +	__u32 nr_sectors;
>> >>  };
>> >
>> > Please put "operation" and "nr_sectors" together, then holes
>> > can be avoided.
>> 
>> Got it 👍
>> 
>> >
>> >>  
>> >>  struct ublk_uring_cmd_pdu {
>> >>  	struct ublk_queue *ubq;
>> >>  };
>> >>  
>> >> +
>> >
>> > ?
>> 
>> Sorry.
>> 
>> >
>> >>  /*
>> >>   * io command is active: sqe cmd is received, and its cqe isn't done
>> >>   *
>> >> @@ -110,6 +116,11 @@ struct ublk_uring_cmd_pdu {
>> >>   */
>> >>  #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
>> >>  
>> >> +/*
>> >> + * Set when IO is Zone Append
>> >> + */
>> >> +#define UBLK_IO_FLAG_ZONE_APPEND 0x10
>> >> +
>> >>  struct ublk_io {
>> >>  	/* userspace buffer address from io cmd */
>> >>  	__u64	addr;
>> >> @@ -184,6 +195,31 @@ struct ublk_params_header {
>> >>  	__u32	len;
>> >>  	__u32	types;
>> >>  };
>> >> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
>> >> +{
>> >> +	return ub->params.types & UBLK_PARAM_TYPE_ZONED;
>> >> +}
>> >> +
>> >> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
>> >> +{
>> >> +	return ub->dev_info.flags & UBLK_F_ZONED;
>> >> +}
>> >> +
>> >> +static int ublk_set_nr_zones(struct ublk_device *ub);
>> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
>> >> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
>> >> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
>> >> +
>> >> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
>> >> +
>> >> +#define ublk_report_zones (NULL)
>> >> +
>> >> +#else
>> >> +
>> >> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> >> +		      unsigned int nr_zones, report_zones_cb cb, void *data);
>> >> +
>> >> +#endif
>> >
>> > Please merge the following "#ifdef CONFIG_BLK_DEV_UBLK_ZONED" with the
>> > above one, then you can avoid the above declarations. Meantime, we don't
>> > add code after MODULE_LICENSE().
>> 
>> Ok 👍
>> 
>> >
>> >>  
>> >>  static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>> >>  {
>> >> @@ -232,7 +268,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
>> >>  		UBLK_TAG_BITS_MASK;
>> >>  }
>> >>  
>> >> -static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>> >> +static int ublk_dev_param_basic_apply(struct ublk_device *ub)
>> >>  {
>> >>  	struct request_queue *q = ub->ub_disk->queue;
>> >>  	const struct ublk_param_basic *p = &ub->params.basic;
>> >> @@ -257,6 +293,11 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
>> >>  		set_disk_ro(ub->ub_disk, true);
>> >>  
>> >>  	set_capacity(ub->ub_disk, p->dev_sectors);
>> >> +
>> >> +	if (ublk_dev_is_zoned(ub))
>> >> +		return ublk_set_nr_zones(ub);
>> >> +
>> >
>> > The above change can be moved into ublk_dev_param_zoned_apply() which
>> > is always done after ublk_dev_param_basic_apply(). 
>> 
>> Ok
>> 
>> >
>> >> +	return 0;
>> >>  }
>> >>  
>> >>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>> >> @@ -286,6 +327,9 @@ static int ublk_validate_params(const struct ublk_device *ub)
>> >>  
>> >>  		if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
>> >>  			return -EINVAL;
>> >> +
>> >> +		if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
>> >> +			return -EINVAL;
>> >>  	} else
>> >>  		return -EINVAL;
>> >>  
>> >> @@ -304,19 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>> >>  	if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>> >>  		return -EINVAL;
>> >>  
>> >> -	return 0;
>> >> +	return ublk_dev_param_zoned_validate(ub);
>> >
>> > Please follow current style of:
>> >
>> > 	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
>> > 		return ublk_dev_param_zoned_validate(ub);
>> >
>> > Then you can avoid lots of check on ublk_dev_params_zoned().
>> 
>> Ok, but then I need
>> 
>> 
>> 	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
>> 		return -EINVAL;
>> 
>> here to check if user is forgetting zoned parameters for zoned ublk dev.
>> Or do you want to drop this check?
>
> OK, zoned is a bit special, then you still can do it:
>
>  	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
>  		return ublk_dev_param_zoned_validate(ub);
> 	else if (ublk_dev_is_zoned(ub))
> 		return -EINVAL;
>
> which is more readable.

Ok

>
>> 
>> >
>> >>  }
>> >>  
>> >>  static int ublk_apply_params(struct ublk_device *ub)
>> >>  {
>> >> +	int ret;
>> >> +
>> >>  	if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
>> >>  		return -EINVAL;
>> >>  
>> >> -	ublk_dev_param_basic_apply(ub);
>> >> +	ret = ublk_dev_param_basic_apply(ub);
>> >> +	if (ret)
>> >> +		return ret;
>> >>  
>> >>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>> >>  		ublk_dev_param_discard_apply(ub);
>> >>  
>> >> +	if (ublk_dev_params_zoned(ub))
>> >> +		return ublk_dev_param_zoned_apply(ub);
>> >> +
>> >>  	return 0;
>> >>  }
>> >>  
>> >> @@ -487,6 +538,7 @@ static const struct block_device_operations ub_fops = {
>> >>  	.owner =	THIS_MODULE,
>> >>  	.open =		ublk_open,
>> >>  	.free_disk =	ublk_free_disk,
>> >> +	.report_zones =	ublk_report_zones,
>> >>  };
>> >>  
>> >>  #define UBLK_MAX_PIN_PAGES	32
>> >> @@ -601,7 +653,8 @@ static inline bool ublk_need_map_req(const struct request *req)
>> >>  
>> >>  static inline bool ublk_need_unmap_req(const struct request *req)
>> >>  {
>> >> -	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
>> >> +	return ublk_rq_has_data(req) &&
>> >> +	       (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
>> >>  }
>> >>  
>> >>  static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
>> >> @@ -685,6 +738,7 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>> >>  {
>> >>  	struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
>> >>  	struct ublk_io *io = &ubq->ios[req->tag];
>> >> +	struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
>> >>  	u32 ublk_op;
>> >>  
>> >>  	switch (req_op(req)) {
>> >> @@ -703,6 +757,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
>> >>  	case REQ_OP_WRITE_ZEROES:
>> >>  		ublk_op = UBLK_IO_OP_WRITE_ZEROES;
>> >>  		break;
>> >> +	case REQ_OP_ZONE_OPEN:
>> >> +		ublk_op = UBLK_IO_OP_ZONE_OPEN;
>> >> +		break;
>> >> +	case REQ_OP_ZONE_CLOSE:
>> >> +		ublk_op = UBLK_IO_OP_ZONE_CLOSE;
>> >> +		break;
>> >> +	case REQ_OP_ZONE_FINISH:
>> >> +		ublk_op = UBLK_IO_OP_ZONE_FINISH;
>> >> +		break;
>> >> +	case REQ_OP_ZONE_RESET:
>> >> +		ublk_op = UBLK_IO_OP_ZONE_RESET;
>> >> +		break;
>> >> +	case REQ_OP_DRV_IN:
>> >> +		ublk_op = pdu->operation;
>> >> +		switch (ublk_op) {
>> >> +		case UBLK_IO_OP_REPORT_ZONES:
>> >> +			iod->op_flags = ublk_op | ublk_req_build_flags(req);
>> >> +			iod->nr_sectors = pdu->nr_sectors;
>> >> +			iod->start_sector = pdu->sector;
>> >> +			return BLK_STS_OK;
>> >> +		default:
>> >> +			return BLK_STS_IOERR;
>> >> +		}
>> >> +	case REQ_OP_ZONE_APPEND:
>> >> +		ublk_op = UBLK_IO_OP_ZONE_APPEND;
>> >> +		io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
>> >> +		break;
>> >> +	case REQ_OP_ZONE_RESET_ALL:
>> >
>> > BLK_STS_NOTSUPP should be returned, since in future we may support it,
>> > and userspace need to know what is wrong.
>> 
>> Ok
>> 
>> >
>> >> +	case REQ_OP_DRV_OUT:
>> >> +		/* We do not support reset_all and drv_out */
>> >> +		fallthrough;
>> >>  	default:
>> >>  		return BLK_STS_IOERR;
>> >>  	}
>> >> @@ -756,7 +841,8 @@ static inline void __ublk_complete_rq(struct request *req)
>> >>  	 *
>> >>  	 * Both the two needn't unmap.
>> >>  	 */
>> >> -	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
>> >> +	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
>> >> +	    req_op(req) != REQ_OP_DRV_IN)
>> >>  		goto exit;
>> >>  
>> >>  	/* for READ request, writing data in iod->addr to rq buffers */
>> >> @@ -1120,6 +1206,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
>> >>  	/* find the io request and complete */
>> >>  	req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
>> >>  
>> >> +	if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
>> >> +		req->__sector = ub_cmd->addr;
>> >> +		io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
>> >> +	}
>> >> +
>> >>  	if (req && likely(!blk_should_fake_timeout(req->q)))
>> >>  		ublk_put_req_ref(ubq, req);
>> >>  }
>> >> @@ -1419,7 +1510,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
>> >>  			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
>> >>  		goto out;
>> >>  
>> >> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> >> +	if (ublk_support_user_copy(ubq) &&
>> >> +	    !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
>> >>  		ret = -EINVAL;
>> >>  		goto out;
>> >>  	}
>> >> @@ -1542,11 +1634,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
>> >>  		int ubuf_dir)
>> >>  {
>> >>  	/* copy ubuf to request pages */
>> >> -	if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
>> >> +	if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
>> >> +	    ubuf_dir == ITER_SOURCE)
>> >>  		return true;
>> >>  
>> >>  	/* copy request pages to ubuf */
>> >> -	if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
>> >> +	if ((req_op(req) == REQ_OP_WRITE ||
>> >> +	     req_op(req) == REQ_OP_ZONE_APPEND) &&
>> >> +	    ubuf_dir == ITER_DEST)
>> >>  		return true;
>> >>  
>> >>  	return false;
>> >> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>> >>  	if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>> >>  		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>> >>  
>> >> -	get_device(&ub->cdev_dev);
>> >>  	ub->dev_info.state = UBLK_S_DEV_LIVE;
>> >> +	ret = ublk_revalidate_disk_zones(ub);
>> >> +	if (ret)
>> >> +		goto out_put_disk;
>> >> +
>> >> +	get_device(&ub->cdev_dev);
>> >>  	ret = add_disk(disk);
>> >>  	if (ret) {
>> >>  		/*
>> >> @@ -2045,6 +2144,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>> >>  	if (ublk_dev_is_user_copy(ub))
>> >>  		ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>> >>  
>> >> +	/* Zoned storage support requires user copy feature */
>> >> +	if (ublk_dev_is_zoned(ub) &&
>> >> +	    (!IS_ENABLED(CONFIG_BLK_DEV_UBLK_ZONED) || !ublk_dev_is_user_copy(ub))) {
>> >> +		ret = -EINVAL;
>> >> +		goto out_free_dev_number;
>> >> +	}
>> >> +
>> >>  	/* We are not ready to support zero copy */
>> >>  	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
>> >>  
>> >> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>> >>  
>> >>  MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
>> >>  MODULE_LICENSE("GPL");
>> >> +
>> >> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
>> >> +
>> >> +static int get_nr_zones(const struct ublk_device *ub)
>> >> +{
>> >> +	const struct ublk_param_basic *p = &ub->params.basic;
>> >> +
>> >> +	if (!p->chunk_sectors)
>> >> +		return 0;
>> >
>> > There isn't zoned device if the above check fails, so no
>> > need to check it.
>> 
>> Ok, but this is called from `ublk_dev_param_zoned_validate()` to
>> validate user sets params correct. Should we not report error to user
>> space during parameter validation if user space sets chunk_sectors to
>> zero for zoned device?
>
> That has been covered in UBLK_PARAM_TYPE_BASIC branch of ublk_validate_params().

Right 👍

>
>> 
>> >
>> >> +
>> >> +	/* Zone size is a power of 2 */
>> >> +	return p->dev_sectors >> ilog2(p->chunk_sectors);
>> >> +}
>> >> +
>> >> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> >> +{
>> >> +	ub->ub_disk->nr_zones = get_nr_zones(ub);
>> >> +	if (!ub->ub_disk->nr_zones)
>> >> +		return -EINVAL;
>> >
>> > Is nr_zones one must for zoned?
>> 
>> Zero zones for a zoned storage device is not allowed, as far as I am
>> aware. Am I mistaken?
>
> OK, never mind, I just didn't see such check in null zoned and virtio-blk.
>
>> 
>> >
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
>> >> +{
>> >> +	if (ublk_dev_is_zoned(ub))
>> >> +		return blk_revalidate_disk_zones(ub->ub_disk, NULL);
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> >> +{
>> >> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> >> +	int nr_zones;
>> >> +
>> >> +	if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
>> >> +		return -EINVAL;
>> >> +
>> >> +	if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
>> >> +		return -EINVAL;
>> >> +
>> >> +	if (!ublk_dev_params_zoned(ub))
>> >> +		return 0;
>> >
>> > The above can be simplified as single check if we follow current
>> > validate/apply code style:
>> >
>> > 	if (!ublk_dev_is_zoned(ub))
>> > 		return -EINVAL;
>> 
>> If we do that we will not be able to check if user space sets the
>> `UBLK_F_ZONED` flag without setting zoned parameters. Should I validate
>> that at call site or drop the check?
>
> Please see above comment, which can be covered as:
>
>  	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
>  		return ublk_dev_param_zoned_validate(ub);
> 	else if (ublk_dev_is_zoned(ub))
> 		return -EINVAL;
>
>> 
>> >> +
>> >> +	if (!p->max_zone_append_sectors)
>> >> +		return -EINVAL;
>> >> +
>> >> +	nr_zones = get_nr_zones(ub);
>> >> +
>> >> +	if (p->max_active_zones > nr_zones)
>> >> +		return -EINVAL;
>> >> +
>> >> +	if (p->max_open_zones > nr_zones)
>> >> +		return -EINVAL;
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> >> +{
>> >> +	const struct ublk_param_zoned *p = &ub->params.zoned;
>> >> +
>> >> +	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
>> >> +	blk_queue_required_elevator_features(ub->ub_disk->queue,
>> >> +					     ELEVATOR_F_ZBD_SEQ_WRITE);
>> >> +	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>> >> +	disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
>> >> +	blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
>> >> +
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +/* Based on virtblk_alloc_report_buffer */
>> >> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
>> >> +				      unsigned int nr_zones, size_t *buflen)
>> >> +{
>> >> +	struct request_queue *q = ublk->ub_disk->queue;
>> >> +	size_t bufsize;
>> >> +	void *buf;
>> >> +
>> >> +	nr_zones = min_t(unsigned int, nr_zones,
>> >> +			 ublk->ub_disk->nr_zones);
>> >> +
>> >> +	bufsize = nr_zones * sizeof(struct blk_zone);
>> >> +	bufsize =
>> >> +		min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
>> >> +	bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
>> >> +
>> >> +	while (bufsize >= sizeof(struct blk_zone)) {
>> >> +		buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
>> >> +		if (buf) {
>> >> +			*buflen = bufsize;
>> >> +			return buf;
>> >> +		}
>> >> +		bufsize >>= 1;
>> >> +	}
>> >> +
>> >> +	*buflen = 0;
>> >> +	return NULL;
>> >> +}
>> >> +
>> >> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> >> +		      unsigned int nr_zones, report_zones_cb cb, void *data)
>> >> +{
>> >> +	struct ublk_device *ub = disk->private_data;
>> >> +	unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
>> >> +	unsigned int first_zone = sector >> ilog2(zone_size_sectors);
>> >> +	unsigned int done_zones = 0;
>> >> +	unsigned int max_zones_per_request;
>> >> +	int ret;
>> >> +	struct blk_zone *buffer;
>> >> +	size_t buffer_length;
>> >> +
>> >> +	if (!ublk_dev_is_zoned(ub))
>> >> +		return -EOPNOTSUPP;
>> >> +
>> >> +	nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
>> >> +			 nr_zones);
>> >> +
>> >> +	buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
>> >> +	if (!buffer)
>> >> +		return -ENOMEM;
>> >> +
>> >> +	max_zones_per_request = buffer_length / sizeof(struct blk_zone);
>> >> +
>> >> +	while (done_zones < nr_zones) {
>> >> +		unsigned int remaining_zones = nr_zones - done_zones;
>> >> +		unsigned int zones_in_request =
>> >> +			min_t(unsigned int, remaining_zones, max_zones_per_request);
>> >> +		struct request *req;
>> >> +		struct ublk_rq_data *pdu;
>> >> +		blk_status_t status;
>> >> +
>> >> +		memset(buffer, 0, buffer_length);
>> >> +
>> >> +		req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
>> >> +		if (IS_ERR(req)) {
>> >> +			ret = PTR_ERR(req);
>> >> +			goto out;
>> >> +		}
>> >> +
>> >> +		pdu = blk_mq_rq_to_pdu(req);
>> >> +		pdu->operation = UBLK_IO_OP_REPORT_ZONES;
>> >> +		pdu->sector = sector;
>> >> +		pdu->nr_sectors = remaining_zones * zone_size_sectors;
>> >> +
>> >> +		ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
>> >> +					GFP_KERNEL);
>> >> +		if (ret) {
>> >> +			blk_mq_free_request(req);
>> >> +			goto out;
>> >> +		}
>> >> +
>> >> +		status = blk_execute_rq(req, 0);
>> >> +		ret = blk_status_to_errno(status);
>> >> +		blk_mq_free_request(req);
>> >> +		if (ret)
>> >> +			goto out;
>> >> +
>> >> +		for (unsigned int i = 0; i < zones_in_request; i++) {
>> >> +			struct blk_zone *zone = buffer + i;
>> >> +
>> >> +			/* A zero length zone means no more zones in this response */
>> >> +			if (!zone->len)
>> >> +				break;
>> >> +
>> >> +			ret = cb(zone, i, data);
>> >> +			if (ret)
>> >> +				goto out;
>> >> +
>> >> +			done_zones++;
>> >> +			sector += zone_size_sectors;
>> >> +
>> >> +		}
>> >> +	}
>> >> +
>> >> +	ret = done_zones;
>> >> +
>> >> +out:
>> >> +	kvfree(buffer);
>> >> +	return ret;
>> >> +}
>> >> +
>> >> +#else
>> >> +
>> >> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> >> +{
>> >> +	return 0;
>> >> +}
>> >> +
>> >> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> >> +{
>> >> +	if (ublk_dev_params_zoned(ub))
>> >> +		return -EINVAL;
>> >> +	return 0;
>> >
>> > Please move the check outside by following current code style, then:
>> >
>> > 		return -EINVAL;
>> >
>> 
>> Ok, but then we move the check for user applying zoned params to
>> non-zoned device when CONFIG_BLK_DEV_ZONED to call site?
>
> Yes, the point is to move check in common code, then not only reduce
> repeated check, but also cleaner.
>
Ok, thanks


BR Andreas