From: John Garry <john.garry@xxxxxxxxxx> [ Upstream commit fce54ed027577517df1e74b7d54dc2b1bd536887 ] If the controller is behind an IOMMU then the IOMMU IOVA caching range can affect performance, as discussed in [0]. Limit the max HW sectors to not exceed this limit. We need to hardcode the value until a proper DMA mapping API is available. [0] https://lore.kernel.org/linux-iommu/20210129092120.1482-1-thunder.leizhen@xxxxxxxxxx/ Link: https://lore.kernel.org/r/1655988119-223714-1-git-send-email-john.garry@xxxxxxxxxx Signed-off-by: John Garry <john.garry@xxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c index 1f5e0688c0c8..15c7451fb30f 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c +++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c @@ -2758,6 +2758,7 @@ static int slave_configure_v3_hw(struct scsi_device *sdev) struct hisi_hba *hisi_hba = shost_priv(shost); struct device *dev = hisi_hba->dev; int ret = sas_slave_configure(sdev); + unsigned int max_sectors; if (ret) return ret; @@ -2775,6 +2776,12 @@ static int slave_configure_v3_hw(struct scsi_device *sdev) } } + /* Set according to IOMMU IOVA caching limit */ + max_sectors = min_t(size_t, queue_max_hw_sectors(sdev->request_queue), + (PAGE_SIZE * 32) >> SECTOR_SHIFT); + + blk_queue_max_hw_sectors(sdev->request_queue, max_sectors); + return 0; } -- 2.35.1
