[SCSI] sd: WRITE SAME(16) / UNMAP support

Implement a function for handling discard requests that sends either
WRITE SAME(16) or UNMAP(10) depending on parameters indicated by the
device in the block limits VPD.

Extract unmap constraints and report them to the block layer.

Based in part by a patch by Christoph Hellwig <hch@lst.de>.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index e374804d26fb..43d3caf268ef 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -60,6 +60,8 @@ struct scsi_disk {
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */
         unsigned        DPOFUA : 1;     /* state of disk DPOFUA bit */
         unsigned        first_scan : 1;
+        unsigned        thin_provisioning : 1;
+        unsigned        unmap : 1;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)