block: rename bio bi_rw to bi_opf

Since commit 63a4cc24867d, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d189e89..8912407 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -806,7 +806,7 @@
 	dd_idx = 0;
 	while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 		dd_idx++;
-	if (head->dev[dd_idx].towrite->bi_rw != sh->dev[dd_idx].towrite->bi_rw ||
+	if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 	    bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 		goto unlock_out;
 
@@ -1003,7 +1003,7 @@
 
 			pr_debug("%s: for %llu schedule op %d on disc %d\n",
 				__func__, (unsigned long long)sh->sector,
-				bi->bi_rw, i);
+				bi->bi_opf, i);
 			atomic_inc(&sh->count);
 			if (sh != head_sh)
 				atomic_inc(&head_sh->count);
@@ -1014,7 +1014,7 @@
 				bi->bi_iter.bi_sector = (sh->sector
 						 + rdev->data_offset);
 			if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
-				bi->bi_rw |= REQ_NOMERGE;
+				bi->bi_opf |= REQ_NOMERGE;
 
 			if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
 				WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
@@ -1055,7 +1055,7 @@
 			pr_debug("%s: for %llu schedule op %d on "
 				 "replacement disc %d\n",
 				__func__, (unsigned long long)sh->sector,
-				rbi->bi_rw, i);
+				rbi->bi_opf, i);
 			atomic_inc(&sh->count);
 			if (sh != head_sh)
 				atomic_inc(&head_sh->count);
@@ -1088,7 +1088,7 @@
 			if (op_is_write(op))
 				set_bit(STRIPE_DEGRADED, &sh->state);
 			pr_debug("skip op %d on disc %d for sector %llu\n",
-				bi->bi_rw, i, (unsigned long long)sh->sector);
+				bi->bi_opf, i, (unsigned long long)sh->sector);
 			clear_bit(R5_LOCKED, &sh->dev[i].flags);
 			set_bit(STRIPE_HANDLE, &sh->state);
 		}
@@ -1619,9 +1619,9 @@
 
 			while (wbi && wbi->bi_iter.bi_sector <
 				dev->sector + STRIPE_SECTORS) {
-				if (wbi->bi_rw & REQ_FUA)
+				if (wbi->bi_opf & REQ_FUA)
 					set_bit(R5_WantFUA, &dev->flags);
-				if (wbi->bi_rw & REQ_SYNC)
+				if (wbi->bi_opf & REQ_SYNC)
 					set_bit(R5_SyncIO, &dev->flags);
 				if (bio_op(wbi) == REQ_OP_DISCARD)
 					set_bit(R5_Discard, &dev->flags);
@@ -5154,7 +5154,7 @@
 	DEFINE_WAIT(w);
 	bool do_prepare;
 
-	if (unlikely(bi->bi_rw & REQ_PREFLUSH)) {
+	if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
 		int ret = r5l_handle_flush_request(conf->log, bi);
 
 		if (ret == 0)
@@ -5237,7 +5237,7 @@
 			(unsigned long long)logical_sector);
 
 		sh = raid5_get_active_stripe(conf, new_sector, previous,
-				       (bi->bi_rw & REQ_RAHEAD), 0);
+				       (bi->bi_opf & REQ_RAHEAD), 0);
 		if (sh) {
 			if (unlikely(previous)) {
 				/* expansion might have moved on while waiting for a
@@ -5305,7 +5305,7 @@
 			set_bit(STRIPE_HANDLE, &sh->state);
 			clear_bit(STRIPE_DELAYED, &sh->state);
 			if ((!sh->batch_head || sh == sh->batch_head) &&
-			    (bi->bi_rw & REQ_SYNC) &&
+			    (bi->bi_opf & REQ_SYNC) &&
 			    !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 				atomic_inc(&conf->preread_active_stripes);
 			release_stripe_plug(mddev, sh);