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authorDmitry Monakhov <dmonakhov@openvz.org>2017-06-29 21:31:14 +0300
committerJens Axboe <axboe@kernel.dk>2017-07-04 01:56:28 +0300
commitf9df1cd99ebd82f05e8f5e0aa7e38cb8d3c791d7 (patch)
treeb5d6222cd50a8e57719e6dbbb57dd5392a07096b /include/linux/bio.h
parentb1fb2c52b2d85f51f36f1661409f9aeef94265ff (diff)
downloadlinux-f9df1cd99ebd82f05e8f5e0aa7e38cb8d3c791d7.tar.xz
bio: add bvec_iter rewind API
Some ->bi_end_io handlers (for example: pi_verify or decrypt handlers) need to know original data vector, but after bio traverse io-stack it may be advanced, splited and relocated many times so it is hard to guess original iterator. Let's add 'bi_done' conter which accounts number of bytes iterator was advanced during it's evolution. Later end_io handler may easily restore original iterator by rewinding iterator to iter->bi_done. Note: this change makes sizeof (struct bvec_iter) multiple to 8 Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> [hch: switched to true/false return] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/bio.h')
-rw-r--r--include/linux/bio.h19
1 files changed, 17 insertions, 2 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h
index d5e8689f86b8..1eba19580185 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -165,14 +165,29 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
{
iter->bi_sector += bytes >> 9;
- if (bio_no_advance_iter(bio))
+ if (bio_no_advance_iter(bio)) {
iter->bi_size -= bytes;
- else {
+ iter->bi_done += bytes;
+ } else {
bvec_iter_advance(bio->bi_io_vec, iter, bytes);
/* TODO: It is reasonable to complete bio with error here. */
}
}
+static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
+ unsigned int bytes)
+{
+ iter->bi_sector -= bytes >> 9;
+
+ if (bio_no_advance_iter(bio)) {
+ iter->bi_size += bytes;
+ iter->bi_done -= bytes;
+ return true;
+ }
+
+ return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
+}
+
#define __bio_for_each_segment(bvl, bio, iter, start) \
for (iter = (start); \
(iter).bi_size && \