[PATCH 6.6 121/301] scsi: libsas: Align SMP request allocation to ARCH_DMA_MINALIGN

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6.6-stable review patch.  If anyone has any objections, please let me know.


From: Yihang Li <liyihang9@xxxxxxxxxx>

[ Upstream commit e675a4fd6d1f8990d3bed5dada3d20edfa000423 ]

This series [1] reduced the kmalloc() minimum alignment on arm64 to 8 bytes
(from 128). In libsas, this will cause SMP requests to be 8-byte aligned
through kmalloc() allocation. However, for hisi_sas hardware, all command
addresses must be 16-byte-aligned. Otherwise, the commands fail to be

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@xxxxxxx [1]
Signed-off-by: Yihang Li <liyihang9@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240328090626.621147-1-liyihang9@xxxxxxxxxx
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
Reviewed-by: Jason Yan <yanaijie@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
 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 5c261005b74e4..f6e6db8b8aba9 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;

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