block: Kill bio_segments()/bi_vcnt usage
When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.
So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.
(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 930cb73..aea9896 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -97,13 +97,46 @@
#define bio_offset(bio) bio_iter_offset((bio), (bio)->bi_iter)
#define bio_iovec(bio) bio_iter_iovec((bio), (bio)->bi_iter)
-#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_iter.bi_idx)
+#define bio_multiple_segments(bio) \
+ ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
#define bio_sectors(bio) ((bio)->bi_iter.bi_size >> 9)
#define bio_end_sector(bio) ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
+/*
+ * Check whether this bio carries any data or not. A NULL bio is allowed.
+ */
+static inline bool bio_has_data(struct bio *bio)
+{
+ if (bio &&
+ bio->bi_iter.bi_size &&
+ !(bio->bi_rw & REQ_DISCARD))
+ return true;
+
+ return false;
+}
+
+static inline bool bio_is_rw(struct bio *bio)
+{
+ if (!bio_has_data(bio))
+ return false;
+
+ if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
+ return false;
+
+ return true;
+}
+
+static inline bool bio_mergeable(struct bio *bio)
+{
+ if (bio->bi_rw & REQ_NOMERGE_FLAGS)
+ return false;
+
+ return true;
+}
+
static inline unsigned int bio_cur_bytes(struct bio *bio)
{
- if (bio->bi_vcnt)
+ if (bio_has_data(bio))
return bio_iovec(bio).bv_len;
else /* dataless requests such as discard */
return bio->bi_iter.bi_size;
@@ -111,7 +144,7 @@
static inline void *bio_data(struct bio *bio)
{
- if (bio->bi_vcnt)
+ if (bio_has_data(bio))
return page_address(bio_page(bio)) + bio_offset(bio);
return NULL;
@@ -221,6 +254,18 @@
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
+static inline unsigned bio_segments(struct bio *bio)
+{
+ unsigned segs = 0;
+ struct bio_vec bv;
+ struct bvec_iter iter;
+
+ bio_for_each_segment(bv, bio, iter)
+ segs++;
+
+ return segs;
+}
+
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
@@ -435,36 +480,6 @@
#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
/*
- * Check whether this bio carries any data or not. A NULL bio is allowed.
- */
-static inline bool bio_has_data(struct bio *bio)
-{
- if (bio && bio->bi_vcnt)
- return true;
-
- return false;
-}
-
-static inline bool bio_is_rw(struct bio *bio)
-{
- if (!bio_has_data(bio))
- return false;
-
- if (bio->bi_rw & REQ_WRITE_SAME)
- return false;
-
- return true;
-}
-
-static inline bool bio_mergeable(struct bio *bio)
-{
- if (bio->bi_rw & REQ_NOMERGE_FLAGS)
- return false;
-
- return true;
-}
-
-/*
* BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
*
* A bio_list anchors a singly-linked list of bios chained through the bi_next