[PATCH 14/27] sd: implement unmapping Write Zeroes

[Christoph Hellwig]

Try to use a write same with unmap bit variant if the device supports it
and the caller allows for it.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Martin K. Petersen <martin.peter...@oracle.com>
Reviewed-by: Hannes Reinecke <h...@suse.com>
---
 drivers/scsi/sd.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d8d9c0bdd93c..001593ed0444 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -803,6 +803,15 @@ static int sd_setup_write_zeroes_cmnd(struct scsi_cmnd 
*cmd)
        u64 sector = blk_rq_pos(rq) >> (ilog2(sdp->sector_size) - 9);
        u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
 
+       if (!(rq->cmd_flags & REQ_NOUNMAP)) {
+               switch (sdkp->provisioning_mode) {
+               case SD_LBP_WS16:
+                       return sd_setup_write_same16_cmnd(cmd, true);
+               case SD_LBP_WS10:
+                       return sd_setup_write_same10_cmnd(cmd, true);
+               }
+       }
+
        if (sdp->no_write_same)
                return BLKPREP_INVALID;
        if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff)
-- 
2.11.0