btrfs: return a btrfs_bio from btrfs_bio_alloc

Return the containing struct btrfs_bio instead of the less type safe
struct bio from btrfs_bio_alloc.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/bio.c

@@ -48,15 +48,17 @@ void btrfs_bio_init(struct btrfs_bio *bbio, struct btrfs_inode *inode,
  * Just like the underlying bio_alloc_bioset it will not fail as it is backed by
  * a mempool.
  */
-struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
+struct btrfs_bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
 				  struct btrfs_inode *inode,
 				  btrfs_bio_end_io_t end_io, void *private)
 {
+	struct btrfs_bio *bbio;
 	struct bio *bio;
 
 	bio = bio_alloc_bioset(NULL, nr_vecs, opf, GFP_NOFS, &btrfs_bioset);
-	btrfs_bio_init(btrfs_bio(bio), inode, end_io, private);
-	return bio;
+	bbio = btrfs_bio(bio);
+	btrfs_bio_init(bbio, inode, end_io, private);
+	return bbio;
 }
 
 static struct bio *btrfs_split_bio(struct btrfs_fs_info *fs_info,

fs/btrfs/bio.h

@@ -75,7 +75,7 @@ void __cold btrfs_bioset_exit(void);
 
 void btrfs_bio_init(struct btrfs_bio *bbio, struct btrfs_inode *inode,
 		    btrfs_bio_end_io_t end_io, void *private);
-struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
+struct btrfs_bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
 				  struct btrfs_inode *inode,
 				  btrfs_bio_end_io_t end_io, void *private);
 

fs/btrfs/extent_io.c

@@ -896,13 +896,13 @@ static void alloc_new_bio(struct btrfs_inode *inode,
 			  u64 disk_bytenr, u64 file_offset)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
-	struct bio *bio;
+	struct btrfs_bio *bbio;
 
-	bio = btrfs_bio_alloc(BIO_MAX_VECS, bio_ctrl->opf, inode,
+	bbio = btrfs_bio_alloc(BIO_MAX_VECS, bio_ctrl->opf, inode,
 			       bio_ctrl->end_io_func, NULL);
-	bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
-	btrfs_bio(bio)->file_offset = file_offset;
-	bio_ctrl->bbio = btrfs_bio(bio);
+	bbio->bio.bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+	bbio->file_offset = file_offset;
+	bio_ctrl->bbio = bbio;
 	bio_ctrl->len_to_oe_boundary = U32_MAX;
 
 	/*
@@ -911,7 +911,7 @@ static void alloc_new_bio(struct btrfs_inode *inode,
 	 * them.
 	 */
 	if (bio_ctrl->compress_type == BTRFS_COMPRESS_NONE &&
-	    btrfs_use_zone_append(btrfs_bio(bio))) {
+	    btrfs_use_zone_append(bbio)) {
 		struct btrfs_ordered_extent *ordered;
 
 		ordered = btrfs_lookup_ordered_extent(inode, file_offset);
@@ -930,8 +930,8 @@ static void alloc_new_bio(struct btrfs_inode *inode,
 		 * to always be set on the last added/replaced device.
 		 * This is a bit odd but has been like that for a long time.
 		 */
-		bio_set_dev(bio, fs_info->fs_devices->latest_dev->bdev);
-		wbc_init_bio(bio_ctrl->wbc, bio);
+		bio_set_dev(&bbio->bio, fs_info->fs_devices->latest_dev->bdev);
+		wbc_init_bio(bio_ctrl->wbc, &bbio->bio);
 	}
 }
 

fs/btrfs/inode.c

@@ -9928,24 +9928,24 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
 		.pending = ATOMIC_INIT(1),
 	};
 	unsigned long i = 0;
-	struct bio *bio;
+	struct btrfs_bio *bbio;
 
 	init_waitqueue_head(&priv.wait);
 
-	bio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ, inode,
+	bbio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ, inode,
 			      btrfs_encoded_read_endio, &priv);
-	bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+	bbio->bio.bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
 
 	do {
 		size_t bytes = min_t(u64, disk_io_size, PAGE_SIZE);
 
-		if (bio_add_page(bio, pages[i], bytes, 0) < bytes) {
+		if (bio_add_page(&bbio->bio, pages[i], bytes, 0) < bytes) {
 			atomic_inc(&priv.pending);
-			btrfs_submit_bio(btrfs_bio(bio), 0);
+			btrfs_submit_bio(bbio, 0);
 
-			bio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ, inode,
+			bbio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ, inode,
 					       btrfs_encoded_read_endio, &priv);
-			bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+			bbio->bio.bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
 			continue;
 		}
 
@@ -9955,7 +9955,7 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
 	} while (disk_io_size);
 
 	atomic_inc(&priv.pending);
-	btrfs_submit_bio(btrfs_bio(bio), 0);
+	btrfs_submit_bio(bbio, 0);
 
 	if (atomic_dec_return(&priv.pending))
 		io_wait_event(priv.wait, !atomic_read(&priv.pending));