block: add bio_for_each_bvec_all()

An upcoming Btrfs fix needs to know the original size of a non-cloned
bios. Rather than accessing the bvec table directly, let's add a
bio_for_each_bvec_all() accessor.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/.clang-format b/.clang-format
index e92e6dd1780d0b2eeebf34d8cbac5bc18bbc8204..a0a96088c74f49a961a80bc0851a84214b0a9f83 100644 (file)
--- a/.clang-format
+++ b/.clang-format
@@ -80,6 +80,7 @@ ForEachMacros:
   - 'ax25_uid_for_each'
   - '__bio_for_each_bvec'
   - 'bio_for_each_bvec'
+  - 'bio_for_each_bvec_all'
   - 'bio_for_each_integrity_vec'
   - '__bio_for_each_segment'
   - 'bio_for_each_segment'

diff --git a/Documentation/block/biovecs.rst b/Documentation/block/biovecs.rst
index ad303a2569d33e7d0799bf67e05dd7245429625b..36771a131b566087fdbc2c4a92982ce7ac9abe9b 100644 (file)
--- a/Documentation/block/biovecs.rst
+++ b/Documentation/block/biovecs.rst
@@ -129,6 +129,7 @@ Usage of helpers:
 ::
 
        bio_for_each_segment_all()
+       bio_for_each_bvec_all()
        bio_first_bvec_all()
        bio_first_page_all()
        bio_last_bvec_all()
@@ -143,4 +144,5 @@ Usage of helpers:
   bio_vec' will contain a multi-page IO vector during the iteration::
 
        bio_for_each_bvec()
+       bio_for_each_bvec_all()
        rq_for_each_bvec()

diff --git a/include/linux/bio.h b/include/linux/bio.h
index a0ee494a6329a8cc48760bceb81ea6ba9f56585e..8e23f51ccfa41b9717f8d5a4191c7b125c27fde1 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -169,6 +169,14 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 #define bio_for_each_bvec(bvl, bio, iter)                      \
        __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
 
+/*
+ * Iterate over all multi-page bvecs. Drivers shouldn't use this version for the
+ * same reasons as bio_for_each_segment_all().
+ */
+#define bio_for_each_bvec_all(bvl, bio, i)             \
+       for (i = 0, bvl = bio_first_bvec_all(bio);      \
+            i < (bio)->bi_vcnt; i++, bvl++)            \
+
 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 
 static inline unsigned bio_segments(struct bio *bio)