block, drivers, cgroup: use op_is_write helper instead of checking for REQ_WRITE

We currently set REQ_WRITE/WRITE for all non READ IOs
like discard, flush, writesame, etc. In the next patches where we
no longer set up the op as a bitmap, we will not be able to
detect a operation direction like writesame by testing if REQ_WRITE is
set.

This patch converts the drivers and cgroup to use the
op_is_write helper. This should just cover the simple
cases. I did dm, md and bcache in their own patches
because they were more involved.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-core.c

@@ -2115,7 +2115,7 @@ blk_qc_t submit_bio(struct bio *bio)
 		else
 			count = bio_sectors(bio);
 
-		if (bio->bi_rw & WRITE) {
+		if (op_is_write(bio_op(bio))) {
 			count_vm_events(PGPGOUT, count);
 		} else {
 			task_io_account_read(bio->bi_iter.bi_size);
@@ -2126,7 +2126,7 @@ blk_qc_t submit_bio(struct bio *bio)
 			char b[BDEVNAME_SIZE];
 			printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
 			current->comm, task_pid_nr(current),
-				(bio->bi_rw & WRITE) ? "WRITE" : "READ",
+				op_is_write(bio_op(bio)) ? "WRITE" : "READ",
 				(unsigned long long)bio->bi_iter.bi_sector,
 				bdevname(bio->bi_bdev, b),
 				count);

block/blk-merge.c

@@ -439,7 +439,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 	}
 
 	if (q->dma_drain_size && q->dma_drain_needed(rq)) {
-		if (rq->cmd_flags & REQ_WRITE)
+		if (op_is_write(req_op(rq)))
 			memset(q->dma_drain_buffer, 0, q->dma_drain_size);
 
 		sg_unmark_end(sg);

drivers/ata/libata-scsi.c

@@ -1190,7 +1190,7 @@ static int atapi_drain_needed(struct request *rq)
 	if (likely(rq->cmd_type != REQ_TYPE_BLOCK_PC))
 		return 0;
 
-	if (!blk_rq_bytes(rq) || (rq->cmd_flags & REQ_WRITE))
+	if (!blk_rq_bytes(rq) || op_is_write(req_op(rq)))
 		return 0;
 
 	return atapi_cmd_type(rq->cmd[0]) == ATAPI_MISC;

drivers/block/loop.c

@@ -447,7 +447,7 @@ static int lo_req_flush(struct loop_device *lo, struct request *rq)
 
 static inline void handle_partial_read(struct loop_cmd *cmd, long bytes)
 {
-	if (bytes < 0 || (cmd->rq->cmd_flags & REQ_WRITE))
+	if (bytes < 0 || op_is_write(req_op(cmd->rq)))
 		return;
 
 	if (unlikely(bytes < blk_rq_bytes(cmd->rq))) {
@@ -541,7 +541,7 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
 
 	pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
 
-	if (rq->cmd_flags & REQ_WRITE) {
+	if (op_is_write(req_op(rq))) {
 		if (rq->cmd_flags & REQ_FLUSH)
 			ret = lo_req_flush(lo, rq);
 		else if (rq->cmd_flags & REQ_DISCARD)
@@ -1672,7 +1672,7 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 static void loop_handle_cmd(struct loop_cmd *cmd)
 {
-	const bool write = cmd->rq->cmd_flags & REQ_WRITE;
+	const bool write = op_is_write(req_op(cmd->rq));
 	struct loop_device *lo = cmd->rq->q->queuedata;
 	int ret = 0;
 

drivers/block/umem.c

@@ -462,7 +462,7 @@ static void process_page(unsigned long data)
 				le32_to_cpu(desc->local_addr)>>9,
 				le32_to_cpu(desc->transfer_size));
 			dump_dmastat(card, control);
-		} else if ((bio->bi_rw & REQ_WRITE) &&
+		} else if (op_is_write(bio_op(bio)) &&
 			   le32_to_cpu(desc->local_addr) >> 9 ==
 				card->init_size) {
 			card->init_size += le32_to_cpu(desc->transfer_size) >> 9;

drivers/scsi/osd/osd_initiator.c

@@ -824,7 +824,7 @@ void osd_req_write(struct osd_request *or,
 {
 	_osd_req_encode_common(or, OSD_ACT_WRITE, obj, offset, len);
 	WARN_ON(or->out.bio || or->out.total_bytes);
-	WARN_ON(0 == (bio->bi_rw & REQ_WRITE));
+	WARN_ON(!op_is_write(bio_op(bio)));
 	or->out.bio = bio;
 	or->out.total_bytes = len;
 }
@@ -875,7 +875,7 @@ void osd_req_read(struct osd_request *or,
 {
 	_osd_req_encode_common(or, OSD_ACT_READ, obj, offset, len);
 	WARN_ON(or->in.bio || or->in.total_bytes);
-	WARN_ON(bio->bi_rw & REQ_WRITE);
+	WARN_ON(op_is_write(bio_op(bio)));
 	or->in.bio = bio;
 	or->in.total_bytes = len;
 }

include/linux/blk-cgroup.h

@@ -601,7 +601,7 @@ static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
 {
 	struct percpu_counter *cnt;
 
-	if (rw & REQ_WRITE)
+	if (op_is_write(rw))
 		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
 	else
 		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];