--- /dev/null
+From 6b7e9cde49691e04314342b7dce90c67ad567fcc Mon Sep 17 00:00:00 2001
+From: "Martin K. Petersen" <martin.petersen@oracle.com>
+Date: Thu, 12 May 2016 22:17:34 -0400
+Subject: 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>
+---
+ drivers/scsi/sd.c | 8 ++++----
+ drivers/scsi/sd.h | 5 +++++
+ 2 files changed, 9 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
+index f459dff..60bff78 100644
+--- 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_CACHE_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
+--- 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:
+--
+cgit v0.12
+