On 3/26/24 21:43, 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@xxxxxxx [1] > Signed-off-by: Yihang Li <liyihang9@xxxxxxxxxx> > --- > Changes since v1: > - Directly modify alloc_smp_req() instead of using handler callback. > --- > drivers/scsi/libsas/sas_expander.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index a2204674b680..941abc7298df 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -135,7 +135,10 @@ 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; > + > + size = ALIGN(size, ARCH_DMA_MINALIGN); > + p = kzalloc(size, GFP_KERNEL); Nit: why not: p = kzalloc(ALIGN(size, ARCH_DMA_MINALIGN), GFP_KERNEL); > if (p) > p[0] = SMP_REQUEST; > return p; Otherwise looks OK to me. John, Unrelated to this patch, but I wonder if the GFP_KERNEL used here shouldn't be GFP_NOIO... Is this ever called in the IO path or error recovery ? -- Damien Le Moal Western Digital Research
