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Commit 6b7e9cde authored May 12, 2016 by Martin K. Petersen

sd: Fix rw_max for devices that report an optimal xfer size



For historic reasons, io_opt is in bytes and max_sectors in block layer
sectors. This interface inconsistency is error prone and should be
fixed. But for 4.4--4.7 let's make the unit difference explicit via a
wrapper function.

Fixes: d0eb20a8 ("sd: Optimal I/O size is in bytes, not sectors")
Cc: stable@vger.kernel.org # 4.4+
Reported-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Andrew Patterson <andrew.patterson@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent fbd83006

drivers/scsi/sd.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -2867,10 +2867,10 @@ static int sd_revalidate_disk(struct gendisk *disk)
		if (sdkp->opt_xfer_blocks &&
		sdkp->opt_xfer_blocks <= dev_max &&
		sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS &&
		sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_SIZE)
		rw_max = q->limits.io_opt =
		sdkp->opt_xfer_blocks * sdp->sector_size;
		else
		logical_to_bytes(sdp, sdkp->opt_xfer_blocks) >= PAGE_SIZE) {
		q->limits.io_opt = logical_to_bytes(sdp, sdkp->opt_xfer_blocks);
		rw_max = logical_to_sectors(sdp, sdkp->opt_xfer_blocks);
		} else
		rw_max = BLK_DEF_MAX_SECTORS;

		/* Combine with controller limits */

drivers/scsi/sd.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -151,6 +151,11 @@ static inline sector_t logical_to_sectors(struct scsi_device *sdev, sector_t blo
		return blocks << (ilog2(sdev->sector_size) - 9);
		}

		static inline unsigned int logical_to_bytes(struct scsi_device *sdev, sector_t blocks)
		{
		return blocks * sdev->sector_size;
		}

		/*
		* A DIF-capable target device can be formatted with different
		* protection schemes. Currently 0 through 3 are defined: