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@xxxxxxx [1] Signed-off-by: Yihang Li <liyihang9@xxxxxxxxxx> Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx> --- 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; -- 2.33.0
