block: Add bio_advance()
This is prep work for immutable bio vecs; we first want to centralize
where bvecs are modified.
Next two patches convert some existing code to use this function.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 669b1cb..fcb4dba 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -248,6 +248,8 @@
struct request_queue;
extern int bio_phys_segments(struct request_queue *, struct bio *);
+extern void bio_advance(struct bio *, unsigned);
+
extern void bio_init(struct bio *);
extern void bio_reset(struct bio *);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index cdf1119..c178d25 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -197,6 +197,8 @@
REQ_SECURE)
#define REQ_CLONE_MASK REQ_COMMON_MASK
+#define BIO_NO_ADVANCE_ITER_MASK (REQ_DISCARD|REQ_WRITE_SAME)
+
/* This mask is used for both bio and request merge checking */
#define REQ_NOMERGE_FLAGS \
(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)