From: Kiwoong Kim kwmad.kim@samsung.com
[ Upstream commit 2b2bfc8aa519f696087475ed8e8c61850c673272 ]
Some SoCs require a single scatterlist entry for smaller than page size, i.e. 4KB. When dispatching commands with more than one scatterlist entry under 4KB in size the following behavior is observed:
A command to read a block range is dispatched with two scatterlist entries that are named AAA and BBB. After dispatching, the host builds two PRDT entries and during transmission, device sends just one DATA IN because device doesn't care about host DMA. The host then transfers the combined amount of data from start address of the area named AAA. As a consequence, the area that follows AAA in memory would be corrupted.
|<------------->| +-------+------------ +-------+ + AAA + (corrupted) ... + BBB + +-------+------------ +-------+
To avoid this we need to enforce page size alignment for sg entries.
Link: https://lore.kernel.org/r/56dddef94f60bd9466fd77e69f64bbbd657ed2a1.161102690... Signed-off-by: Kiwoong Kim kwmad.kim@samsung.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/ufs/ufshcd.c | 2 ++ drivers/scsi/ufs/ufshcd.h | 4 ++++ 2 files changed, 6 insertions(+)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index e602c08d740b..97d9d5d99adc 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -4748,6 +4748,8 @@ static int ufshcd_slave_configure(struct scsi_device *sdev) struct request_queue *q = sdev->request_queue;
blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1); + if (hba->quirks & UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE) + blk_queue_update_dma_alignment(q, PAGE_SIZE - 1);
if (ufshcd_is_rpm_autosuspend_allowed(hba)) sdev->rpm_autosuspend = 1; diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index fcca4e15c8cd..a0bc118f9188 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -550,6 +550,10 @@ enum ufshcd_quirks { */ UFSHCD_QUIRK_SKIP_DEF_UNIPRO_TIMEOUT_SETTING = 1 << 13,
+ /* + * This quirk allows only sg entries aligned with page size. + */ + UFSHCD_QUIRK_ALIGN_SG_WITH_PAGE_SIZE = 1 << 13, };
enum ufshcd_caps {