[PATCH v3] scsi: libsas: Allocation SMP request is aligned to 16B

From: Yihang Li
Date: Thu Mar 28 2024 - 02:27:23 EST


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.

So use 16B as the alignment for SMP request.

Link: https://lkml.kernel.org/r/20230612153201.554742-1-catalin.marinas@xxxxxxx [1]
Signed-off-by: Yihang Li <liyihang9@xxxxxxxxxx>
---
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..5ddbd00d5c76 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, 16), GFP_KERNEL);
if (p)
p[0] = SMP_REQUEST;
return p;
--
2.33.0