| Message ID | 20240328090626.621147-1-liyihang9@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v4] scsi: libsas: Allocation SMP request is aligned to ARCH_DMA_MINALIGN | expand |
On 28/03/2024 09:06, Yihang Li wrote: > This series [1] reducing the kmalloc() minimum alignment on arm64 to 8 > (from 128). In libsas, this will cause SMP requests to be 8-byte-aligned > through kmalloc() allocation. However, for the hisi_sas hardware, all > commands address must be 16-byte-aligned. Otherwise, the commands fail to > be executed. > > ARCH_DMA_MINALIGN represents the minimum (static) alignment for safe DMA > operations, so use ARCH_DMA_MINALIGN as the alignment for SMP request. I'd say that we must align to at least ARCH_DMA_MINALIGN for memory which we want to map for DMA. ARCH_DMA_MINALIGN would never be less than the 16B requirement for hisi_sas, so just align to ARCH_DMA_MINALIGN. > > Link: https://urldefense.com/v3/__https://lkml.kernel.org/r/20230612153201.554742-1-catalin.marinas@arm.com__;!!ACWV5N9M2RV99hQ!LbkCJSfklWds8mk0UGjtg0qRNpWuAc-ibudDMl7sI_Qip4Hd6WNqHZmRbuJfObd4fcZXj0sC8nGTs1UbA5PlCA$ [1] > Signed-off-by: Yihang Li <liyihang9@huawei.com> > Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: John Garry <john.g.garry@oracle.com> > --- > Changes since v3: > - Still aligned to ARCH_DMA_MINALIGN for safe DMA operations. > > Changes since v2: > - Use 16B as alignment for SMP requests instead of ARCH_DMA_MINALIGN. > > Changes since v1: > - Directly modify alloc_smp_req() instead of using handler callback. > --- > drivers/scsi/libsas/sas_expander.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index a2204674b680..c989d182fc75 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -135,7 +135,7 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size, > > static inline void *alloc_smp_req(int size) > { > - u8 *p = kzalloc(size, GFP_KERNEL); > + u8 *p = kzalloc(ALIGN(size, ARCH_DMA_MINALIGN), GFP_KERNEL); > if (p) > p[0] = SMP_REQUEST; > return p;
On 2024/3/28 17:06, Yihang Li wrote: > This series [1] reducing the kmalloc() minimum alignment on arm64 to 8 > (from 128). In libsas, this will cause SMP requests to be 8-byte-aligned > through kmalloc() allocation. However, for the hisi_sas hardware, all > commands address must be 16-byte-aligned. Otherwise, the commands fail to > be executed. > > ARCH_DMA_MINALIGN represents the minimum (static) alignment for safe DMA > operations, so use ARCH_DMA_MINALIGN as the alignment for SMP request. > > Link: https://lkml.kernel.org/r/20230612153201.554742-1-catalin.marinas@arm.com [1] > Signed-off-by: Yihang Li <liyihang9@huawei.com> > Reviewed-by: Damien Le Moal <dlemoal@kernel.org> > --- > Changes since v3: > - Still aligned to ARCH_DMA_MINALIGN for safe DMA operations. > > Changes since v2: > - Use 16B as alignment for SMP requests instead of ARCH_DMA_MINALIGN. > > Changes since v1: > - Directly modify alloc_smp_req() instead of using handler callback. > --- > drivers/scsi/libsas/sas_expander.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index a2204674b680..c989d182fc75 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -135,7 +135,7 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size, > > static inline void *alloc_smp_req(int size) > { > - u8 *p = kzalloc(size, GFP_KERNEL); > + u8 *p = kzalloc(ALIGN(size, ARCH_DMA_MINALIGN), GFP_KERNEL); > if (p) > p[0] = SMP_REQUEST; > return p; > Reviewed-by: Jason Yan <yanaijie@huawei.com> Thanks, Jason
On Thu, 28 Mar 2024 17:06:26 +0800, Yihang Li wrote: > This series [1] reducing the kmalloc() minimum alignment on arm64 to 8 > (from 128). In libsas, this will cause SMP requests to be 8-byte-aligned > through kmalloc() allocation. However, for the hisi_sas hardware, all > commands address must be 16-byte-aligned. Otherwise, the commands fail to > be executed. > > ARCH_DMA_MINALIGN represents the minimum (static) alignment for safe DMA > operations, so use ARCH_DMA_MINALIGN as the alignment for SMP request. > > [...] Applied to 6.9/scsi-fixes, thanks! [1/1] scsi: libsas: Allocation SMP request is aligned to ARCH_DMA_MINALIGN https://git.kernel.org/mkp/scsi/c/e675a4fd6d1f
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index a2204674b680..c989d182fc75 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -135,7 +135,7 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size, static inline void *alloc_smp_req(int size) { - u8 *p = kzalloc(size, GFP_KERNEL); + u8 *p = kzalloc(ALIGN(size, ARCH_DMA_MINALIGN), GFP_KERNEL); if (p) p[0] = SMP_REQUEST; return p;