btrfs: move more work into btrfs_end_bioc

Assign ->mirror_num and ->bi_status in btrfs_end_bioc instead of
duplicating the logic in the callers.  Also remove the bio argument as
it always must be bioc->orig_bio and the now pointless bioc_error that
did nothing but assign bi_sector to the same value just sampled in the
caller.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -6616,19 +6616,29 @@ int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	return __btrfs_map_block(fs_info, op, logical, length, bioc_ret, 0, 1);
 }
 
-static inline void btrfs_end_bioc(struct btrfs_io_context *bioc, struct bio *bio)
+static inline void btrfs_end_bioc(struct btrfs_io_context *bioc)
 {
-	bio->bi_private = bioc->private;
-	bio->bi_end_io = bioc->end_io;
-	bio_endio(bio);
+	struct bio *orig_bio = bioc->orig_bio;
 
+	btrfs_bio(orig_bio)->mirror_num = bioc->mirror_num;
+	orig_bio->bi_private = bioc->private;
+	orig_bio->bi_end_io = bioc->end_io;
+
+	/*
+	 * Only send an error to the higher layers if it is beyond the tolerance
+	 * threshold.
+	 */
+	if (atomic_read(&bioc->error) > bioc->max_errors)
+		orig_bio->bi_status = BLK_STS_IOERR;
+	else
+		orig_bio->bi_status = BLK_STS_OK;
+	bio_endio(orig_bio);
 	btrfs_put_bioc(bioc);
 }
 
 static void btrfs_end_bio(struct bio *bio)
 {
 	struct btrfs_io_context *bioc = bio->bi_private;
-	int is_orig_bio = 0;
 
 	if (bio->bi_status) {
 		atomic_inc(&bioc->error);
@@ -6649,35 +6659,12 @@ static void btrfs_end_bio(struct bio *bio)
 		}
 	}
 
-	if (bio == bioc->orig_bio)
-		is_orig_bio = 1;
-
-	btrfs_bio_counter_dec(bioc->fs_info);
-
-	if (atomic_dec_and_test(&bioc->stripes_pending)) {
-		if (!is_orig_bio) {
+	if (bio != bioc->orig_bio)
 		bio_put(bio);
-			bio = bioc->orig_bio;
-		}
 
-		btrfs_bio(bio)->mirror_num = bioc->mirror_num;
-		/* only send an error to the higher layers if it is
-		 * beyond the tolerance of the btrfs bio
-		 */
-		if (atomic_read(&bioc->error) > bioc->max_errors) {
-			bio->bi_status = BLK_STS_IOERR;
-		} else {
-			/*
-			 * this bio is actually up to date, we didn't
-			 * go over the max number of errors
-			 */
-			bio->bi_status = BLK_STS_OK;
-		}
-
-		btrfs_end_bioc(bioc, bio);
-	} else if (!is_orig_bio) {
-		bio_put(bio);
-	}
+	btrfs_bio_counter_dec(bioc->fs_info);
+	if (atomic_dec_and_test(&bioc->stripes_pending))
+		btrfs_end_bioc(bioc);
 }
 
 static void submit_stripe_bio(struct btrfs_io_context *bioc, struct bio *bio,
@@ -6715,23 +6702,6 @@ static void submit_stripe_bio(struct btrfs_io_context *bioc, struct bio *bio,
 	submit_bio(bio);
 }
 
-static void bioc_error(struct btrfs_io_context *bioc, struct bio *bio, u64 logical)
-{
-	atomic_inc(&bioc->error);
-	if (atomic_dec_and_test(&bioc->stripes_pending)) {
-		/* Should be the original bio. */
-		WARN_ON(bio != bioc->orig_bio);
-
-		btrfs_bio(bio)->mirror_num = bioc->mirror_num;
-		bio->bi_iter.bi_sector = logical >> 9;
-		if (atomic_read(&bioc->error) > bioc->max_errors)
-			bio->bi_status = BLK_STS_IOERR;
-		else
-			bio->bi_status = BLK_STS_OK;
-		btrfs_end_bioc(bioc, bio);
-	}
-}
-
 blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 			   int mirror_num)
 {
@@ -6790,7 +6760,9 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 						   &dev->dev_state) ||
 		    (btrfs_op(first_bio) == BTRFS_MAP_WRITE &&
 		    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))) {
-			bioc_error(bioc, first_bio, logical);
+			atomic_inc(&bioc->error);
+			if (atomic_dec_and_test(&bioc->stripes_pending))
+				btrfs_end_bioc(bioc);
 			continue;
 		}