Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

[Sergei Shtylyov]

On 10/17/2017 11:05 AM, Huacai Chen wrote:

> In non-coherent DMA mode, kernel uses cache flushing operations to
> maintain I/O coherency, so in ata_do_dev_read_id() the DMA buffer
> should be aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer
> and a kernel structure share a same cache line, and if the kernel
> structure has dirty data, cache_invalidate (no writeback) will cause
> data corruption.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
>   drivers/ata/libata-core.c | 15 +++++++++++++--
>   1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index ee4c1ec..e134955 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -1833,8 +1833,19 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
>   unsigned int ata_do_dev_read_id(struct ata_device *dev,
>   					struct ata_taskfile *tf, u16 *id)
>   {
> -	return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE,
> -				     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
> +	u16 *devid;
> +	int res, size = sizeof(u16) * ATA_ID_WORDS;
> +
> +	if (IS_ALIGNED((unsigned long)id, dma_get_cache_alignment(&dev->tdev)))
> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, size, 0);
> +	else {
> +		devid = kmalloc(size, GFP_KERNEL);
> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, devid, size, 0);
> +		memcpy(id, devid, size);
> +		kfree(devid);
> +	}
> +
> +	return res;

    This function is called only for the PIO mode commands, so I doubt this is 
necessary...

MBR, Sergei

Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

[Alan Cox]

>     This function is called only for the PIO mode commands, so I doubt this is 
> necessary...

That is true but there are platforms out there that issue disk level PIO
commands via DMA (or can do so). Indeed the Cyrix MediaGX could do that
in the 1990s but I never add support 8)

So I think it makes sense to allocate the buffers DMA aligned, but it
doesn't seem to explain the situation in this case and I think it would
be helpful to know what platform and ATA driver is tripping this and wny
they are the only people in the universe to have the problem.

Alan

Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

[Tejun Heo]

On Tue, Oct 17, 2017 at 04:05:42PM +0800, Huacai Chen wrote:
> In non-coherent DMA mode, kernel uses cache flushing operations to
> maintain I/O coherency, so in ata_do_dev_read_id() the DMA buffer
> should be aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer
> and a kernel structure share a same cache line, and if the kernel
> structure has dirty data, cache_invalidate (no writeback) will cause
> data corruption.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
>  drivers/ata/libata-core.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index ee4c1ec..e134955 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -1833,8 +1833,19 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
>  unsigned int ata_do_dev_read_id(struct ata_device *dev,
>  					struct ata_taskfile *tf, u16 *id)
>  {
> -	return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE,
> -				     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
> +	u16 *devid;
> +	int res, size = sizeof(u16) * ATA_ID_WORDS;
> +
> +	if (IS_ALIGNED((unsigned long)id, dma_get_cache_alignment(&dev->tdev)))
> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, size, 0);
> +	else {
> +		devid = kmalloc(size, GFP_KERNEL);
> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, devid, size, 0);
> +		memcpy(id, devid, size);
> +		kfree(devid);
> +	}
> +
> +	return res;

Hmm... I think it'd be a lot better to ensure that the buffers are
aligned properly to begin with.  There are only two buffers which are
used for id reading - ata_port->sector_buf and ata_device->id.  Both
are embedded arrays but making them separately allocated aligned
buffers shouldn't be difficult.

Thanks.

-- 
tejun

Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

[Matt Redfearn]

On 18/10/17 14:03, Tejun Heo wrote:
> On Tue, Oct 17, 2017 at 04:05:42PM +0800, Huacai Chen wrote:
>> In non-coherent DMA mode, kernel uses cache flushing operations to
>> maintain I/O coherency, so in ata_do_dev_read_id() the DMA buffer
>> should be aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer
>> and a kernel structure share a same cache line, and if the kernel
>> structure has dirty data, cache_invalidate (no writeback) will cause
>> data corruption.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Huacai Chen <chenhc@lemote.com>
>> ---
>>   drivers/ata/libata-core.c | 15 +++++++++++++--
>>   1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index ee4c1ec..e134955 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -1833,8 +1833,19 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
>>   unsigned int ata_do_dev_read_id(struct ata_device *dev,
>>   					struct ata_taskfile *tf, u16 *id)
>>   {
>> -	return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE,
>> -				     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
>> +	u16 *devid;
>> +	int res, size = sizeof(u16) * ATA_ID_WORDS;
>> +
>> +	if (IS_ALIGNED((unsigned long)id, dma_get_cache_alignment(&dev->tdev)))
>> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, size, 0);
>> +	else {
>> +		devid = kmalloc(size, GFP_KERNEL);
>> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, devid, size, 0);
>> +		memcpy(id, devid, size);
>> +		kfree(devid);
>> +	}
>> +
>> +	return res;
> Hmm... I think it'd be a lot better to ensure that the buffers are
> aligned properly to begin with.  There are only two buffers which are
> used for id reading - ata_port->sector_buf and ata_device->id.  Both
> are embedded arrays but making them separately allocated aligned
> buffers shouldn't be difficult.
>
> Thanks.

FWIW, I agree that the buffers used for DMA should be split out from the 
structure. We ran into this problem on MIPS last year, 
4ee34ea3a12396f35b26d90a094c75db95080baa ("libata: Align ata_device's id 
on a cacheline") partially fixed it, but likely should have also 
cacheline aligned the following devslp_timing in the struct such that we 
guarantee that members of the struct not used for DMA do not share the 
same cacheline as the DMA buffer. Not having this means that 
architectures, such as MIPS, which in some cases have to perform manual 
invalidation of DMA buffer can clobber valid adjacent data if it is in 
the same cacheline.

Thanks,
Matt

Re: [PATCH V8 5/5] libata: Align DMA buffer to dma_get_cache_alignment()

[Matt Redfearn]

On 18/10/17 14:03, Tejun Heo wrote:
> On Tue, Oct 17, 2017 at 04:05:42PM +0800, Huacai Chen wrote:
>> In non-coherent DMA mode, kernel uses cache flushing operations to
>> maintain I/O coherency, so in ata_do_dev_read_id() the DMA buffer
>> should be aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer
>> and a kernel structure share a same cache line, and if the kernel
>> structure has dirty data, cache_invalidate (no writeback) will cause
>> data corruption.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Huacai Chen <chenhc@lemote.com>
>> ---
>>   drivers/ata/libata-core.c | 15 +++++++++++++--
>>   1 file changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
>> index ee4c1ec..e134955 100644
>> --- a/drivers/ata/libata-core.c
>> +++ b/drivers/ata/libata-core.c
>> @@ -1833,8 +1833,19 @@ static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
>>   unsigned int ata_do_dev_read_id(struct ata_device *dev,
>>   					struct ata_taskfile *tf, u16 *id)
>>   {
>> -	return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE,
>> -				     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
>> +	u16 *devid;
>> +	int res, size = sizeof(u16) * ATA_ID_WORDS;
>> +
>> +	if (IS_ALIGNED((unsigned long)id, dma_get_cache_alignment(&dev->tdev)))
>> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, id, size, 0);
>> +	else {
>> +		devid = kmalloc(size, GFP_KERNEL);
>> +		res = ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE, devid, size, 0);
>> +		memcpy(id, devid, size);
>> +		kfree(devid);
>> +	}
>> +
>> +	return res;
> Hmm... I think it'd be a lot better to ensure that the buffers are
> aligned properly to begin with.  There are only two buffers which are
> used for id reading - ata_port->sector_buf and ata_device->id.  Both
> are embedded arrays but making them separately allocated aligned
> buffers shouldn't be difficult.
>
> Thanks.

FWIW, I agree that the buffers used for DMA should be split out from the 
structure. We ran into this problem on MIPS last year, 
4ee34ea3a12396f35b26d90a094c75db95080baa ("libata: Align ata_device's id 
on a cacheline") partially fixed it, but likely should have also 
cacheline aligned the following devslp_timing in the struct such that we 
guarantee that members of the struct not used for DMA do not share the 
same cacheline as the DMA buffer. Not having this means that 
architectures, such as MIPS, which in some cases have to perform manual 
invalidation of DMA buffer can clobber valid adjacent data if it is in 
the same cacheline.

Thanks,
Matt

Re: [PATCH V8 1/5] dma-mapping: Rework dma_get_cache_alignment()

[Mark Greer]

On Tue, Oct 17, 2017 at 04:05:38PM +0800, Huacai Chen wrote:
> Make dma_get_cache_alignment() to accept a 'dev' argument. As a result,
> it can return different alignments due to different devices' I/O cache
> coherency.
> 
> Currently, ARM/ARM64 and MIPS support coherent & noncoherent devices
> co-exist. This may be extended in the future, so add a new function
> pointer (i.e, get_cache_alignment) in 'struct dma_map_ops' as a generic
> solution.

Hi Huacai.

> diff --git a/drivers/tty/serial/mpsc.c b/drivers/tty/serial/mpsc.c
> index 67ffecc..c708457 100644
> --- a/drivers/tty/serial/mpsc.c
> +++ b/drivers/tty/serial/mpsc.c
> @@ -81,19 +81,19 @@
>   * Number of Tx & Rx descriptors must be powers of 2.
>   */
>  #define	MPSC_RXR_ENTRIES	32
> -#define	MPSC_RXRE_SIZE		dma_get_cache_alignment()
> +#define	MPSC_RXRE_SIZE		dma_get_cache_alignment(dma_dev)

I would much prefer that you add a parameter to the macro to avoid forcing
a non-flexible and non-obvious variable definition wherever it is used.
What I mean is something like:

#define MPSC_RXRE_SIZE(d)		dma_get_cache_alignment(d)

Similarly for all of the other macros and where they're used.

Thanks,

Mark
--

Re: [PATCH V8 1/5] dma-mapping: Rework dma_get_cache_alignment()

[Christoph Hellwig]

On Wed, Oct 18, 2017 at 10:23:36AM -0700, Mark Greer wrote:
> >  #define	MPSC_RXR_ENTRIES	32
> > -#define	MPSC_RXRE_SIZE		dma_get_cache_alignment()
> > +#define	MPSC_RXRE_SIZE		dma_get_cache_alignment(dma_dev)
> 
> I would much prefer that you add a parameter to the macro to avoid forcing
> a non-flexible and non-obvious variable definition wherever it is used.
> What I mean is something like:
> 
> #define MPSC_RXRE_SIZE(d)		dma_get_cache_alignment(d)
> 
> Similarly for all of the other macros and where they're used.

Agreed.  Except for that the patch looks fine to me, though.

Re: [PATCH V8 3/5] scsi: Align block queue to dma_get_cache_alignment()

[Christoph Hellwig]

On Tue, Oct 17, 2017 at 04:05:40PM +0800, Huacai Chen wrote:
> In non-coherent DMA mode, kernel uses cache flushing operations to
> maintain I/O coherency, so scsi's block queue should be aligned to
> ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer and a kernel structure
> share a same cache line, and if the kernel structure has dirty data,
> cache_invalidate (no writeback) will cause data corruption.

Looks fine to, and I like cleaning up the arcane 0x03 as wel.

Re: [PATCH V8 4/5] libsas: Align SMP req/resp to dma_get_cache_alignment()

[Marek Szyprowski]

Hi Huacai,

On 2017-10-17 10:05, Huacai Chen wrote:
> In non-coherent DMA mode, kernel uses cache flushing operations to
> maintain I/O coherency, so libsas's SMP request/response should be
> aligned to ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer and a kernel
> structure share a same cache line, and if the kernel structure has
> dirty data, cache_invalidate (no writeback) will cause data corruption.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
>   drivers/scsi/libsas/sas_expander.c | 93 +++++++++++++++++++++++---------------
>   1 file changed, 57 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
> index 6b4fd23..124a44b 100644
> --- a/drivers/scsi/libsas/sas_expander.c
> +++ b/drivers/scsi/libsas/sas_expander.c
> @@ -164,17 +164,17 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size,
>   
>   /* ---------- Allocations ---------- */
>   
> -static inline void *alloc_smp_req(int size)
> +static inline void *alloc_smp_req(int size, int align)
>   {
> -	u8 *p = kzalloc(size, GFP_KERNEL);
> +	u8 *p = kzalloc(ALIGN(size, align), GFP_KERNEL);

If I remember correctly, kernel guarantees that each kmalloced buffer is
always at least aligned to the CPU cache line, so CPU cache can be
invalidated on the allocated buffer without corrupting anything else.
Taking this into account, I wonder if the above change make sense.

Have you experienced any problems without this change?

>   	if (p)
>   		p[0] = SMP_REQUEST;
>   	return p;
>   }
>   
> -static inline void *alloc_smp_resp(int size)
> +static inline void *alloc_smp_resp(int size, int align)
>   {
> -	return kzalloc(size, GFP_KERNEL);
> +	return kzalloc(ALIGN(size, align), GFP_KERNEL);

Save a above.

>   }
>   
>   static char sas_route_char(struct domain_device *dev, struct ex_phy *phy)
> @@ -403,15 +403,17 @@ static int sas_ex_phy_discover_helper(struct domain_device *dev, u8 *disc_req,
>   int sas_ex_phy_discover(struct domain_device *dev, int single)
>   {
>   	struct expander_device *ex = &dev->ex_dev;
> -	int  res = 0;
> +	int  res = 0, align;
>   	u8   *disc_req;
>   	u8   *disc_resp;
>   
> -	disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	disc_req = alloc_smp_req(DISCOVER_REQ_SIZE, align);
>   	if (!disc_req)
>   		return -ENOMEM;
>   
> -	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
> +	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE, align);
>   	if (!disc_resp) {
>   		kfree(disc_req);
>   		return -ENOMEM;
> @@ -480,14 +482,15 @@ static int sas_ex_general(struct domain_device *dev)
>   {
>   	u8 *rg_req;
>   	struct smp_resp *rg_resp;
> -	int res;
> -	int i;
> +	int i, res, align;
>   
> -	rg_req = alloc_smp_req(RG_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	rg_req = alloc_smp_req(RG_REQ_SIZE, align);
>   	if (!rg_req)
>   		return -ENOMEM;
>   
> -	rg_resp = alloc_smp_resp(RG_RESP_SIZE);
> +	rg_resp = alloc_smp_resp(RG_RESP_SIZE, align);
>   	if (!rg_resp) {
>   		kfree(rg_req);
>   		return -ENOMEM;
> @@ -552,13 +555,15 @@ static int sas_ex_manuf_info(struct domain_device *dev)
>   {
>   	u8 *mi_req;
>   	u8 *mi_resp;
> -	int res;
> +	int res, align;
>   
> -	mi_req = alloc_smp_req(MI_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	mi_req = alloc_smp_req(MI_REQ_SIZE, align);
>   	if (!mi_req)
>   		return -ENOMEM;
>   
> -	mi_resp = alloc_smp_resp(MI_RESP_SIZE);
> +	mi_resp = alloc_smp_resp(MI_RESP_SIZE, align);
>   	if (!mi_resp) {
>   		kfree(mi_req);
>   		return -ENOMEM;
> @@ -593,13 +598,15 @@ int sas_smp_phy_control(struct domain_device *dev, int phy_id,
>   {
>   	u8 *pc_req;
>   	u8 *pc_resp;
> -	int res;
> +	int res, align;
> +
> +	align = dma_get_cache_alignment(&dev->phy->dev);
>   
> -	pc_req = alloc_smp_req(PC_REQ_SIZE);
> +	pc_req = alloc_smp_req(PC_REQ_SIZE, align);
>   	if (!pc_req)
>   		return -ENOMEM;
>   
> -	pc_resp = alloc_smp_resp(PC_RESP_SIZE);
> +	pc_resp = alloc_smp_resp(PC_RESP_SIZE, align);
>   	if (!pc_resp) {
>   		kfree(pc_req);
>   		return -ENOMEM;
> @@ -664,17 +671,19 @@ static int sas_dev_present_in_domain(struct asd_sas_port *port,
>   #define RPEL_RESP_SIZE	32
>   int sas_smp_get_phy_events(struct sas_phy *phy)
>   {
> -	int res;
> +	int res, align;
>   	u8 *req;
>   	u8 *resp;
>   	struct sas_rphy *rphy = dev_to_rphy(phy->dev.parent);
>   	struct domain_device *dev = sas_find_dev_by_rphy(rphy);
>   
> -	req = alloc_smp_req(RPEL_REQ_SIZE);
> +	align = dma_get_cache_alignment(&phy->dev);
> +
> +	req = alloc_smp_req(RPEL_REQ_SIZE, align);
>   	if (!req)
>   		return -ENOMEM;
>   
> -	resp = alloc_smp_resp(RPEL_RESP_SIZE);
> +	resp = alloc_smp_resp(RPEL_RESP_SIZE, align);
>   	if (!resp) {
>   		kfree(req);
>   		return -ENOMEM;
> @@ -709,7 +718,8 @@ int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
>   			    struct smp_resp *rps_resp)
>   {
>   	int res;
> -	u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE);
> +	int align = dma_get_cache_alignment(&dev->phy->dev);
> +	u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE, align);
>   	u8 *resp = (u8 *)rps_resp;
>   
>   	if (!rps_req)
> @@ -1398,7 +1408,7 @@ static int sas_check_parent_topology(struct domain_device *child)
>   static int sas_configure_present(struct domain_device *dev, int phy_id,
>   				 u8 *sas_addr, int *index, int *present)
>   {
> -	int i, res = 0;
> +	int i, res = 0, align;
>   	struct expander_device *ex = &dev->ex_dev;
>   	struct ex_phy *phy = &ex->ex_phy[phy_id];
>   	u8 *rri_req;
> @@ -1406,12 +1416,13 @@ static int sas_configure_present(struct domain_device *dev, int phy_id,
>   
>   	*present = 0;
>   	*index = 0;
> +	align = dma_get_cache_alignment(&dev->phy->dev);
>   
> -	rri_req = alloc_smp_req(RRI_REQ_SIZE);
> +	rri_req = alloc_smp_req(RRI_REQ_SIZE, align);
>   	if (!rri_req)
>   		return -ENOMEM;
>   
> -	rri_resp = alloc_smp_resp(RRI_RESP_SIZE);
> +	rri_resp = alloc_smp_resp(RRI_RESP_SIZE, align);
>   	if (!rri_resp) {
>   		kfree(rri_req);
>   		return -ENOMEM;
> @@ -1472,15 +1483,17 @@ static int sas_configure_present(struct domain_device *dev, int phy_id,
>   static int sas_configure_set(struct domain_device *dev, int phy_id,
>   			     u8 *sas_addr, int index, int include)
>   {
> -	int res;
> +	int res, align;
>   	u8 *cri_req;
>   	u8 *cri_resp;
>   
> -	cri_req = alloc_smp_req(CRI_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	cri_req = alloc_smp_req(CRI_REQ_SIZE, align);
>   	if (!cri_req)
>   		return -ENOMEM;
>   
> -	cri_resp = alloc_smp_resp(CRI_RESP_SIZE);
> +	cri_resp = alloc_smp_resp(CRI_RESP_SIZE, align);
>   	if (!cri_resp) {
>   		kfree(cri_req);
>   		return -ENOMEM;
> @@ -1689,10 +1702,12 @@ int sas_discover_root_expander(struct domain_device *dev)
>   static int sas_get_phy_discover(struct domain_device *dev,
>   				int phy_id, struct smp_resp *disc_resp)
>   {
> -	int res;
> +	int res, align;
>   	u8 *disc_req;
>   
> -	disc_req = alloc_smp_req(DISCOVER_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	disc_req = alloc_smp_req(DISCOVER_REQ_SIZE, align);
>   	if (!disc_req)
>   		return -ENOMEM;
>   
> @@ -1715,10 +1730,12 @@ static int sas_get_phy_discover(struct domain_device *dev,
>   static int sas_get_phy_change_count(struct domain_device *dev,
>   				    int phy_id, int *pcc)
>   {
> -	int res;
> +	int res, align;
>   	struct smp_resp *disc_resp;
>   
> -	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE, align);
>   	if (!disc_resp)
>   		return -ENOMEM;
>   
> @@ -1733,11 +1750,13 @@ static int sas_get_phy_change_count(struct domain_device *dev,
>   static int sas_get_phy_attached_dev(struct domain_device *dev, int phy_id,
>   				    u8 *sas_addr, enum sas_device_type *type)
>   {
> -	int res;
> +	int res, align;
>   	struct smp_resp *disc_resp;
>   	struct discover_resp *dr;
>   
> -	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE, align);
>   	if (!disc_resp)
>   		return -ENOMEM;
>   	dr = &disc_resp->disc;
> @@ -1787,15 +1806,17 @@ static int sas_find_bcast_phy(struct domain_device *dev, int *phy_id,
>   
>   static int sas_get_ex_change_count(struct domain_device *dev, int *ecc)
>   {
> -	int res;
> +	int res, align;
>   	u8  *rg_req;
>   	struct smp_resp  *rg_resp;
>   
> -	rg_req = alloc_smp_req(RG_REQ_SIZE);
> +	align = dma_get_cache_alignment(&dev->phy->dev);
> +
> +	rg_req = alloc_smp_req(RG_REQ_SIZE, align);
>   	if (!rg_req)
>   		return -ENOMEM;
>   
> -	rg_resp = alloc_smp_resp(RG_RESP_SIZE);
> +	rg_resp = alloc_smp_resp(RG_RESP_SIZE, align);
>   	if (!rg_resp) {
>   		kfree(rg_req);
>   		return -ENOMEM;

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland

Re: [PATCH V8 4/5] libsas: Align SMP req/resp to dma_get_cache_alignment()

[Christoph Hellwig]

On Tue, Oct 17, 2017 at 01:55:43PM +0200, Marek Szyprowski wrote:
> If I remember correctly, kernel guarantees that each kmalloced buffer is
> always at least aligned to the CPU cache line, so CPU cache can be
> invalidated on the allocated buffer without corrupting anything else.

Yes, from slab.h:

/*
 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
 * alignment larger than the alignment of a 64-bit integer.
 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
 */
#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
#else
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
#endif

Mips sets this for a few subarchitectures, but it seems like you need
to set it for yours as well.

Re: [PATCH V8 4/5] libsas: Align SMP req/resp to dma_get_cache_alignment()

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 9547 bytes --]

Hi Huacai,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc5 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Huacai-Chen/dma-mapping-Rework-dma_get_cache_alignment/20171020-050317
config: um-allyesconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All errors (new ones prefixed by >>):

   drivers/scsi/libsas/sas_expander.c: In function 'sas_ex_phy_discover':
>> drivers/scsi/libsas/sas_expander.c:410:10: error: implicit declaration of function 'dma_get_cache_alignment' [-Werror=implicit-function-declaration]
     align = dma_get_cache_alignment(&dev->phy->dev);
             ^~~~~~~~~~~~~~~~~~~~~~~
   Cyclomatic Complexity 5 include/linux/compiler.h:__write_once_size
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:atomic_set
   Cyclomatic Complexity 2 arch/x86/include/asm/bitops.h:set_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:constant_test_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:fls64
   Cyclomatic Complexity 1 arch/x86/include/uapi/asm/swab.h:__arch_swab64
   Cyclomatic Complexity 1 include/uapi/linux/swab.h:__fswab16
   Cyclomatic Complexity 1 include/uapi/linux/swab.h:__fswab64
   Cyclomatic Complexity 1 include/linux/log2.h:__ilog2_u64
   Cyclomatic Complexity 1 include/linux/list.h:INIT_LIST_HEAD
   Cyclomatic Complexity 2 include/linux/list.h:__list_add
   Cyclomatic Complexity 1 include/linux/list.h:list_add_tail
   Cyclomatic Complexity 1 include/linux/list.h:__list_del
   Cyclomatic Complexity 2 include/linux/list.h:__list_del_entry
   Cyclomatic Complexity 1 include/linux/list.h:list_del
   Cyclomatic Complexity 1 include/asm-generic/getorder.h:__get_order
   Cyclomatic Complexity 1 include/linux/spinlock.h:spinlock_check
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_lock_irq
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock_irq
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock_irqrestore
   Cyclomatic Complexity 1 include/linux/refcount.h:refcount_set
   Cyclomatic Complexity 28 include/linux/slab.h:kmalloc_index
   Cyclomatic Complexity 68 include/linux/slab.h:kmalloc_large
   Cyclomatic Complexity 5 include/linux/slab.h:kmalloc
   Cyclomatic Complexity 1 include/linux/slab.h:kzalloc
   Cyclomatic Complexity 1 include/linux/kref.h:kref_init
   Cyclomatic Complexity 1 include/linux/kref.h:kref_get
   Cyclomatic Complexity 2 include/linux/kref.h:kref_put
   Cyclomatic Complexity 1 include/scsi/scsi.h:scsi_to_u32
   Cyclomatic Complexity 1 include/scsi/sas_ata.h:dev_is_sata
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_internal.h:sas_fill_in_rphy
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_internal.h:sas_add_parent_port
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_internal.h:sas_alloc_device
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_internal.h:sas_put_device
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:alloc_smp_req
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:alloc_smp_resp
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_route_char
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:to_dev_type
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:dev_type_flutter
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_print_parent_topology_bug
   Cyclomatic Complexity 17 drivers/scsi/libsas/sas_expander.c:smp_execute_task_sg
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:smp_execute_task
   Cyclomatic Complexity 21 drivers/scsi/libsas/sas_expander.c:sas_configure_present
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_get_phy_discover
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_get_phy_change_count
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_find_bcast_phy
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_get_ex_change_count
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:smp_task_timedout
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:smp_task_done
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:ex_assign_report_general
   Cyclomatic Complexity 22 drivers/scsi/libsas/sas_expander.c:sas_check_eeds
   Cyclomatic Complexity 23 drivers/scsi/libsas/sas_expander.c:sas_check_parent_topology
   Cyclomatic Complexity 11 drivers/scsi/libsas/sas_expander.c:sas_configure_set
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_configure_phy
   Cyclomatic Complexity 11 drivers/scsi/libsas/sas_expander.c:sas_configure_parent
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_configure_routing
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_disable_routing
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_find_sub_addr
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_get_phy_attached_dev
   Cyclomatic Complexity 35 drivers/scsi/libsas/sas_expander.c:sas_set_ex_phy
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_ex_phy_discover_helper
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_ex_general
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:ex_assign_manuf_info
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_manuf_info
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_ex_get_linkrate
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_join_wide_port
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_dev_present_in_domain
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_end_dev
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_unregister_ex_tree
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_unregister_devs_sas_addr
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_find_bcast_dev
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_to_ata
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_phy_discover
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_expander_discover
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_smp_phy_control
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:sas_ex_disable_phy
   Cyclomatic Complexity 13 drivers/scsi/libsas/sas_expander.c:sas_check_ex_subtractive_boundary
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_discover_expander
   Cyclomatic Complexity 9 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_expander
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_ex_disable_port
   Cyclomatic Complexity 14 drivers/scsi/libsas/sas_expander.c:sas_check_level_subtractive_boundary
   Cyclomatic Complexity 40 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_dev
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_devices
   Cyclomatic Complexity 8 drivers/scsi/libsas/sas_expander.c:sas_ex_level_discovery
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_ex_bfs_disc
   Cyclomatic Complexity 8 drivers/scsi/libsas/sas_expander.c:sas_discover_bfs_by_root_level
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_discover_bfs_by_root
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_discover_new
   Cyclomatic Complexity 22 drivers/scsi/libsas/sas_expander.c:sas_rediscover_dev
   Cyclomatic Complexity 9 drivers/scsi/libsas/sas_expander.c:sas_rediscover
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_smp_get_phy_events
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_discover_root_expander
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_revalidate_domain
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_smp_handler
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:_GLOBAL__sub_I_65535_0_sas_ex_to_ata
   cc1: some warnings being treated as errors

vim +/dma_get_cache_alignment +410 drivers/scsi/libsas/sas_expander.c

   402	
   403	int sas_ex_phy_discover(struct domain_device *dev, int single)
   404	{
   405		struct expander_device *ex = &dev->ex_dev;
   406		int  res = 0, align;
   407		u8   *disc_req;
   408		u8   *disc_resp;
   409	
 > 410		align = dma_get_cache_alignment(&dev->phy->dev);
   411	
   412		disc_req = alloc_smp_req(DISCOVER_REQ_SIZE, align);
   413		if (!disc_req)
   414			return -ENOMEM;
   415	
   416		disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE, align);
   417		if (!disc_resp) {
   418			kfree(disc_req);
   419			return -ENOMEM;
   420		}
   421	
   422		disc_req[1] = SMP_DISCOVER;
   423	
   424		if (0 <= single && single < ex->num_phys) {
   425			res = sas_ex_phy_discover_helper(dev, disc_req, disc_resp, single);
   426		} else {
   427			int i;
   428	
   429			for (i = 0; i < ex->num_phys; i++) {
   430				res = sas_ex_phy_discover_helper(dev, disc_req,
   431								 disc_resp, i);
   432				if (res)
   433					goto out_err;
   434			}
   435		}
   436	out_err:
   437		kfree(disc_resp);
   438		kfree(disc_req);
   439		return res;
   440	}
   441	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 19622 bytes --]

Re: [PATCH V8 4/5] libsas: Align SMP req/resp to dma_get_cache_alignment()

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 9547 bytes --]

Hi Huacai,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc5 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Huacai-Chen/dma-mapping-Rework-dma_get_cache_alignment/20171020-050317
config: um-allyesconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=um 

All errors (new ones prefixed by >>):

   drivers/scsi/libsas/sas_expander.c: In function 'sas_ex_phy_discover':
>> drivers/scsi/libsas/sas_expander.c:410:10: error: implicit declaration of function 'dma_get_cache_alignment' [-Werror=implicit-function-declaration]
     align = dma_get_cache_alignment(&dev->phy->dev);
             ^~~~~~~~~~~~~~~~~~~~~~~
   Cyclomatic Complexity 5 include/linux/compiler.h:__write_once_size
   Cyclomatic Complexity 1 arch/x86/include/asm/atomic.h:atomic_set
   Cyclomatic Complexity 2 arch/x86/include/asm/bitops.h:set_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:constant_test_bit
   Cyclomatic Complexity 1 arch/x86/include/asm/bitops.h:fls64
   Cyclomatic Complexity 1 arch/x86/include/uapi/asm/swab.h:__arch_swab64
   Cyclomatic Complexity 1 include/uapi/linux/swab.h:__fswab16
   Cyclomatic Complexity 1 include/uapi/linux/swab.h:__fswab64
   Cyclomatic Complexity 1 include/linux/log2.h:__ilog2_u64
   Cyclomatic Complexity 1 include/linux/list.h:INIT_LIST_HEAD
   Cyclomatic Complexity 2 include/linux/list.h:__list_add
   Cyclomatic Complexity 1 include/linux/list.h:list_add_tail
   Cyclomatic Complexity 1 include/linux/list.h:__list_del
   Cyclomatic Complexity 2 include/linux/list.h:__list_del_entry
   Cyclomatic Complexity 1 include/linux/list.h:list_del
   Cyclomatic Complexity 1 include/asm-generic/getorder.h:__get_order
   Cyclomatic Complexity 1 include/linux/spinlock.h:spinlock_check
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_lock_irq
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock_irq
   Cyclomatic Complexity 1 include/linux/spinlock.h:spin_unlock_irqrestore
   Cyclomatic Complexity 1 include/linux/refcount.h:refcount_set
   Cyclomatic Complexity 28 include/linux/slab.h:kmalloc_index
   Cyclomatic Complexity 68 include/linux/slab.h:kmalloc_large
   Cyclomatic Complexity 5 include/linux/slab.h:kmalloc
   Cyclomatic Complexity 1 include/linux/slab.h:kzalloc
   Cyclomatic Complexity 1 include/linux/kref.h:kref_init
   Cyclomatic Complexity 1 include/linux/kref.h:kref_get
   Cyclomatic Complexity 2 include/linux/kref.h:kref_put
   Cyclomatic Complexity 1 include/scsi/scsi.h:scsi_to_u32
   Cyclomatic Complexity 1 include/scsi/sas_ata.h:dev_is_sata
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_internal.h:sas_fill_in_rphy
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_internal.h:sas_add_parent_port
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_internal.h:sas_alloc_device
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_internal.h:sas_put_device
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:alloc_smp_req
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:alloc_smp_resp
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_route_char
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:to_dev_type
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:dev_type_flutter
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_print_parent_topology_bug
   Cyclomatic Complexity 17 drivers/scsi/libsas/sas_expander.c:smp_execute_task_sg
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:smp_execute_task
   Cyclomatic Complexity 21 drivers/scsi/libsas/sas_expander.c:sas_configure_present
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_get_phy_discover
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_get_phy_change_count
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_find_bcast_phy
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_get_ex_change_count
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:smp_task_timedout
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:smp_task_done
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:ex_assign_report_general
   Cyclomatic Complexity 22 drivers/scsi/libsas/sas_expander.c:sas_check_eeds
   Cyclomatic Complexity 23 drivers/scsi/libsas/sas_expander.c:sas_check_parent_topology
   Cyclomatic Complexity 11 drivers/scsi/libsas/sas_expander.c:sas_configure_set
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_configure_phy
   Cyclomatic Complexity 11 drivers/scsi/libsas/sas_expander.c:sas_configure_parent
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_configure_routing
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_disable_routing
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_find_sub_addr
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_get_phy_attached_dev
   Cyclomatic Complexity 35 drivers/scsi/libsas/sas_expander.c:sas_set_ex_phy
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_ex_phy_discover_helper
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_ex_general
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:ex_assign_manuf_info
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_manuf_info
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_ex_get_linkrate
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_join_wide_port
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_dev_present_in_domain
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_end_dev
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_unregister_ex_tree
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_unregister_devs_sas_addr
   Cyclomatic Complexity 10 drivers/scsi/libsas/sas_expander.c:sas_find_bcast_dev
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_to_ata
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_phy_discover
   Cyclomatic Complexity 3 drivers/scsi/libsas/sas_expander.c:sas_expander_discover
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_smp_phy_control
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:sas_ex_disable_phy
   Cyclomatic Complexity 13 drivers/scsi/libsas/sas_expander.c:sas_check_ex_subtractive_boundary
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_discover_expander
   Cyclomatic Complexity 9 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_expander
   Cyclomatic Complexity 6 drivers/scsi/libsas/sas_expander.c:sas_ex_disable_port
   Cyclomatic Complexity 14 drivers/scsi/libsas/sas_expander.c:sas_check_level_subtractive_boundary
   Cyclomatic Complexity 40 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_dev
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_ex_discover_devices
   Cyclomatic Complexity 8 drivers/scsi/libsas/sas_expander.c:sas_ex_level_discovery
   Cyclomatic Complexity 2 drivers/scsi/libsas/sas_expander.c:sas_ex_bfs_disc
   Cyclomatic Complexity 8 drivers/scsi/libsas/sas_expander.c:sas_discover_bfs_by_root_level
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_discover_bfs_by_root
   Cyclomatic Complexity 12 drivers/scsi/libsas/sas_expander.c:sas_discover_new
   Cyclomatic Complexity 22 drivers/scsi/libsas/sas_expander.c:sas_rediscover_dev
   Cyclomatic Complexity 9 drivers/scsi/libsas/sas_expander.c:sas_rediscover
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_smp_get_phy_events
   Cyclomatic Complexity 4 drivers/scsi/libsas/sas_expander.c:sas_discover_root_expander
   Cyclomatic Complexity 5 drivers/scsi/libsas/sas_expander.c:sas_ex_revalidate_domain
   Cyclomatic Complexity 7 drivers/scsi/libsas/sas_expander.c:sas_smp_handler
   Cyclomatic Complexity 1 drivers/scsi/libsas/sas_expander.c:_GLOBAL__sub_I_65535_0_sas_ex_to_ata
   cc1: some warnings being treated as errors

vim +/dma_get_cache_alignment +410 drivers/scsi/libsas/sas_expander.c

   402	
   403	int sas_ex_phy_discover(struct domain_device *dev, int single)
   404	{
   405		struct expander_device *ex = &dev->ex_dev;
   406		int  res = 0, align;
   407		u8   *disc_req;
   408		u8   *disc_resp;
   409	
 > 410		align = dma_get_cache_alignment(&dev->phy->dev);
   411	
   412		disc_req = alloc_smp_req(DISCOVER_REQ_SIZE, align);
   413		if (!disc_req)
   414			return -ENOMEM;
   415	
   416		disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE, align);
   417		if (!disc_resp) {
   418			kfree(disc_req);
   419			return -ENOMEM;
   420		}
   421	
   422		disc_req[1] = SMP_DISCOVER;
   423	
   424		if (0 <= single && single < ex->num_phys) {
   425			res = sas_ex_phy_discover_helper(dev, disc_req, disc_resp, single);
   426		} else {
   427			int i;
   428	
   429			for (i = 0; i < ex->num_phys; i++) {
   430				res = sas_ex_phy_discover_helper(dev, disc_req,
   431								 disc_resp, i);
   432				if (res)
   433					goto out_err;
   434			}
   435		}
   436	out_err:
   437		kfree(disc_resp);
   438		kfree(disc_req);
   439		return res;
   440	}
   441	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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