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: d0eb20a863ba ("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>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index f459dff..60bff78 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -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 */

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 654630b..765a6f1 100644 (file)
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -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: