* [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits
@ 2009-04-27 11:35 Nikanth Karthikesan
2009-04-27 11:46 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Nikanth Karthikesan @ 2009-04-27 11:35 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
The __REQ_NR_BITS was being used by blk_dump_rq_flags() long back, while
printing the individual request flag bits as strings to limit to the used
bits. But it does not use it now. Remove unused enum.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
---
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ba54c83..f41abbb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -118,7 +118,6 @@ enum rq_flag_bits {
__REQ_COPY_USER, /* contains copies of user pages */
__REQ_INTEGRITY, /* integrity metadata has been remapped */
__REQ_NOIDLE, /* Don't anticipate more IO after this one */
- __REQ_NR_BITS, /* stops here */
};
#define REQ_RW (1 << __REQ_RW)
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits
2009-04-27 11:35 [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits Nikanth Karthikesan
@ 2009-04-27 11:46 ` Jens Axboe
2009-04-27 12:05 ` Nikanth Karthikesan
0 siblings, 1 reply; 4+ messages in thread
From: Jens Axboe @ 2009-04-27 11:46 UTC (permalink / raw)
To: Nikanth Karthikesan; +Cc: linux-kernel
On Mon, Apr 27 2009, Nikanth Karthikesan wrote:
> The __REQ_NR_BITS was being used by blk_dump_rq_flags() long back, while
> printing the individual request flag bits as strings to limit to the used
> bits. But it does not use it now. Remove unused enum.
>
> Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
>
> ---
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index ba54c83..f41abbb 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -118,7 +118,6 @@ enum rq_flag_bits {
> __REQ_COPY_USER, /* contains copies of user pages */
> __REQ_INTEGRITY, /* integrity metadata has been remapped */
> __REQ_NOIDLE, /* Don't anticipate more IO after this one */
> - __REQ_NR_BITS, /* stops here */
> };
>
> #define REQ_RW (1 << __REQ_RW)
Lets turn it into something useful instead. It's meant to catch someone
adding too many flags, how about something like this:
Untested ;-)
diff --git a/block/blk-core.c b/block/blk-core.c
index d73eb76..e62ef94 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2159,6 +2159,8 @@ EXPORT_SYMBOL(kblockd_schedule_work);
int __init blk_dev_init(void)
{
+ BUILD_BUG_ON(__REQ_NR_BITS > 8 * sizeof(int));
+
kblockd_workqueue = create_workqueue("kblockd");
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
--
Jens Axboe
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits
2009-04-27 11:46 ` Jens Axboe
@ 2009-04-27 12:05 ` Nikanth Karthikesan
2009-04-27 12:11 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Nikanth Karthikesan @ 2009-04-27 12:05 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel
On Monday 27 April 2009 17:16:33 Jens Axboe wrote:
> On Mon, Apr 27 2009, Nikanth Karthikesan wrote:
> > The __REQ_NR_BITS was being used by blk_dump_rq_flags() long back, while
> > printing the individual request flag bits as strings to limit to the used
> > bits. But it does not use it now. Remove unused enum.
> >
> > Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
> >
> > ---
> >
> > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > index ba54c83..f41abbb 100644
> > --- a/include/linux/blkdev.h
> > +++ b/include/linux/blkdev.h
> > @@ -118,7 +118,6 @@ enum rq_flag_bits {
> > __REQ_COPY_USER, /* contains copies of user pages */
> > __REQ_INTEGRITY, /* integrity metadata has been remapped */
> > __REQ_NOIDLE, /* Don't anticipate more IO after this one */
> > - __REQ_NR_BITS, /* stops here */
> > };
> >
> > #define REQ_RW (1 << __REQ_RW)
>
> Lets turn it into something useful instead. It's meant to catch someone
> adding too many flags, how about something like this:
>
> Untested ;-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index d73eb76..e62ef94 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -2159,6 +2159,8 @@ EXPORT_SYMBOL(kblockd_schedule_work);
>
> int __init blk_dev_init(void)
> {
> + BUILD_BUG_ON(__REQ_NR_BITS > 8 * sizeof(int));
> +
> kblockd_workqueue = create_workqueue("kblockd");
> if (!kblockd_workqueue)
> panic("Failed to create kblockd\n");
Good idea. How about this?
Thanks
Nikanth
Catch trying to use more bits than request->cmd_flags has.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
---
diff --git a/block/blk-core.c b/block/blk-core.c
index 07ab754..218f745 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2156,6 +2156,9 @@ EXPORT_SYMBOL(kblockd_schedule_work);
int __init blk_dev_init(void)
{
+ BUILD_BUG_ON(__REQ_NR_BITS > 8 *
+ sizeof(((struct request *)0)->cmd_flags));
+
kblockd_workqueue = create_workqueue("kblockd");
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits
2009-04-27 12:05 ` Nikanth Karthikesan
@ 2009-04-27 12:11 ` Jens Axboe
0 siblings, 0 replies; 4+ messages in thread
From: Jens Axboe @ 2009-04-27 12:11 UTC (permalink / raw)
To: Nikanth Karthikesan; +Cc: linux-kernel
On Mon, Apr 27 2009, Nikanth Karthikesan wrote:
> On Monday 27 April 2009 17:16:33 Jens Axboe wrote:
> > On Mon, Apr 27 2009, Nikanth Karthikesan wrote:
> > > The __REQ_NR_BITS was being used by blk_dump_rq_flags() long back, while
> > > printing the individual request flag bits as strings to limit to the used
> > > bits. But it does not use it now. Remove unused enum.
> > >
> > > Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
> > >
> > > ---
> > >
> > > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > > index ba54c83..f41abbb 100644
> > > --- a/include/linux/blkdev.h
> > > +++ b/include/linux/blkdev.h
> > > @@ -118,7 +118,6 @@ enum rq_flag_bits {
> > > __REQ_COPY_USER, /* contains copies of user pages */
> > > __REQ_INTEGRITY, /* integrity metadata has been remapped */
> > > __REQ_NOIDLE, /* Don't anticipate more IO after this one */
> > > - __REQ_NR_BITS, /* stops here */
> > > };
> > >
> > > #define REQ_RW (1 << __REQ_RW)
> >
> > Lets turn it into something useful instead. It's meant to catch someone
> > adding too many flags, how about something like this:
> >
> > Untested ;-)
> >
> > diff --git a/block/blk-core.c b/block/blk-core.c
> > index d73eb76..e62ef94 100644
> > --- a/block/blk-core.c
> > +++ b/block/blk-core.c
> > @@ -2159,6 +2159,8 @@ EXPORT_SYMBOL(kblockd_schedule_work);
> >
> > int __init blk_dev_init(void)
> > {
> > + BUILD_BUG_ON(__REQ_NR_BITS > 8 * sizeof(int));
> > +
> > kblockd_workqueue = create_workqueue("kblockd");
> > if (!kblockd_workqueue)
> > panic("Failed to create kblockd\n");
>
> Good idea. How about this?
That's fine, better explains the check. It doesn't matter in practice
though, since we will be restricted to 32 flags even on 64-bit archs (as
long as we support 32-bit archs).
I'll add it, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-04-27 12:11 UTC | newest]
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2009-04-27 11:35 [PATCH] Cleanup: Remove unused __REQ_NR_BITS from enum rq_flag_bits Nikanth Karthikesan
2009-04-27 11:46 ` Jens Axboe
2009-04-27 12:05 ` Nikanth Karthikesan
2009-04-27 12:11 ` Jens Axboe
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