block: better op and flags encoding

Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields.  This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits.  Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 3bf5d33800ab..ddaf28d0988f 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -581,15 +581,14 @@ static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
 /**
  * blkg_rwstat_add - add a value to a blkg_rwstat
  * @rwstat: target blkg_rwstat
- * @op: REQ_OP
- * @op_flags: rq_flag_bits
+ * @op: REQ_OP and flags
  * @val: value to add
  *
  * Add @val to @rwstat.  The counters are chosen according to @rw.  The
  * caller is responsible for synchronizing calls to this function.
  */
 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
-				   int op, int op_flags, uint64_t val)
+				   unsigned int op, uint64_t val)
 {
 	struct percpu_counter *cnt;
 
@@ -600,7 +599,7 @@ static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
 
 	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
 
-	if (op_flags & REQ_SYNC)
+	if (op & REQ_SYNC)
 		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
 	else
 		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
@@ -705,9 +704,9 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
 
 	if (!throtl) {
 		blkg = blkg ?: q->root_blkg;
-		blkg_rwstat_add(&blkg->stat_bytes, bio_op(bio), bio->bi_opf,
+		blkg_rwstat_add(&blkg->stat_bytes, bio->bi_opf,
 				bio->bi_iter.bi_size);
-		blkg_rwstat_add(&blkg->stat_ios, bio_op(bio), bio->bi_opf, 1);
+		blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1);
 	}
 
 	rcu_read_unlock();