block: consistently use GFP_NOIO instead of __GFP_NORECLAIM

Same numerical value (for now at least), but a much better documentation
of intent.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/scsi/scsi_lib.c

@@ -273,7 +273,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 	rq = scsi_req(req);
 
 	if (bufflen &&	blk_rq_map_kern(sdev->request_queue, req,
-					buffer, bufflen, __GFP_RECLAIM))
+					buffer, bufflen, GFP_NOIO))
 		goto out;
 
 	rq->cmd_len = COMMAND_SIZE(cmd[0]);