block, dm-crypt, btrfs: Introduce bio_flags()

Introduce the bio_flags() macro. Ensure that the second argument of
bio_set_op_attrs() only contains flags and no operation. This patch
does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Chris Mason <clm@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Josef Bacik <jbacik@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/md/dm-crypt.c

@@ -1136,7 +1136,7 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 	clone->bi_private = io;
 	clone->bi_end_io  = crypt_endio;
 	clone->bi_bdev    = cc->dev->bdev;
-	bio_set_op_attrs(clone, bio_op(io->base_bio), io->base_bio->bi_opf);
+	bio_set_op_attrs(clone, bio_op(io->base_bio), bio_flags(io->base_bio));
 }
 
 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)

fs/btrfs/inode.c

@@ -8412,7 +8412,7 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
 	if (!bio)
 		return -ENOMEM;
 
-	bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_opf);
+	bio_set_op_attrs(bio, bio_op(orig_bio), bio_flags(orig_bio));
 	bio->bi_private = dip;
 	bio->bi_end_io = btrfs_end_dio_bio;
 	btrfs_io_bio(bio)->logical = file_offset;
@@ -8450,7 +8450,8 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
 						  start_sector, GFP_NOFS);
 			if (!bio)
 				goto out_err;
-			bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_opf);
+			bio_set_op_attrs(bio, bio_op(orig_bio),
+					 bio_flags(orig_bio));
 			bio->bi_private = dip;
 			bio->bi_end_io = btrfs_end_dio_bio;
 			btrfs_io_bio(bio)->logical = file_offset;

include/linux/blk_types.h

@@ -90,11 +90,12 @@ struct bio {
 };
 
 #define BIO_OP_SHIFT	(8 * FIELD_SIZEOF(struct bio, bi_opf) - REQ_OP_BITS)
+#define bio_flags(bio)	((bio)->bi_opf & ((1 << BIO_OP_SHIFT) - 1))
 #define bio_op(bio)	((bio)->bi_opf >> BIO_OP_SHIFT)
 
 #define bio_set_op_attrs(bio, op, op_flags) do {		\
 	WARN_ON(op >= (1 << REQ_OP_BITS));			\
-	(bio)->bi_opf &= ((1 << BIO_OP_SHIFT) - 1);		\
+	(bio)->bi_opf = bio_flags(bio);				\
 	(bio)->bi_opf |= ((unsigned int) (op) << BIO_OP_SHIFT);	\
 	(bio)->bi_opf |= op_flags;				\
 } while (0)