sd: add a sd_disable_write_same helper

Add helper to disable WRITE SAME when it is not supported and use it
instead of sd_config_write_same in the I/O completion handler.  This
avoids touching more fields than required in the I/O completion handler
and  prepares for converting sd to use the atomic queue limits API.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: Christoph Hellwig

drivers/scsi/sd.c

@@ -1004,6 +1004,13 @@ static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
 	return sd_setup_write_same10_cmnd(cmd, false);
 }
 
+static void sd_disable_write_same(struct scsi_disk *sdkp)
+{
+	sdkp->device->no_write_same = 1;
+	sdkp->max_ws_blocks = 0;
+	blk_queue_max_write_zeroes_sectors(sdkp->disk->queue, 0);
+}
+
 static void sd_config_write_same(struct scsi_disk *sdkp)
 {
 	struct request_queue *q = sdkp->disk->queue;
@@ -2258,8 +2265,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 				if (SCpnt->cmnd[1] & 8) { /* UNMAP */
 					sd_disable_discard(sdkp);
 				} else {
-					sdkp->device->no_write_same = 1;
-					sd_config_write_same(sdkp);
+					sd_disable_write_same(sdkp);
 					req->rq_flags |= RQF_QUIET;
 				}
 				break;