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Groups > linux.kernel > #1616328
| From | Dmitry Monakhov <dmonakhov@openvz.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 8/9] bio: add bvec_iter rewind API |
| Date | 2017-04-04 21:00 +0200 |
| Message-ID | <tsBQl-hL-9@gated-at.bofh.it> (permalink) |
| References | <tsBQl-hL-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
include/linux/bio.h | 21 +++++++++++++++++++--
include/linux/bvec.h | 26 ++++++++++++++++++++++++++
2 files changed, 45 insertions(+), 2 deletions(-)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 12b7fcd..491fb0c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -166,9 +166,10 @@ 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 {
int err;
err = bvec_iter_advance(bio->bi_io_vec, iter, bytes);
if (unlikely(err))
@@ -176,6 +177,22 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
}
}
+static inline void bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
+ unsigned bytes)
+{
+ iter->bi_sector -= bytes >> 9;
+
+ if (bio_no_advance_iter(bio)) {
+ iter->bi_size += bytes;
+ iter->bi_done -= bytes;
+ } else {
+ int err;
+ err = bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
+ if (unlikely(err))
+ bio->bi_error = err;
+ }
+}
+
#define __bio_for_each_segment(bvl, bio, iter, start) \
for (iter = (start); \
(iter).bi_size && \
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 984a7a8..35cb97b 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -40,6 +40,8 @@ struct bvec_iter {
unsigned int bi_idx; /* current index into bvl_vec */
+ unsigned int bi_done; /* number of bytes completed */
+
unsigned int bi_bvec_done; /* number of bytes completed in
current bvec */
};
@@ -84,6 +86,7 @@ static inline int bvec_iter_advance(const struct bio_vec *bv,
bytes -= len;
iter->bi_size -= len;
iter->bi_bvec_done += len;
+ iter->bi_done += len;
if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
iter->bi_bvec_done = 0;
@@ -93,6 +96,29 @@ static inline int bvec_iter_advance(const struct bio_vec *bv,
return 0;
}
+static inline int bvec_iter_rewind(const struct bio_vec *bv,
+ struct bvec_iter *iter,
+ unsigned bytes)
+{
+ while (bytes) {
+ unsigned len = min(bytes, iter->bi_bvec_done);
+ if (iter->bi_bvec_done == 0 ) {
+ if (WARN_ONCE(iter->bi_idx == 0,
+ "Attempted to rewind iter beyond "
+ "bvec's boundaries\n")) {
+ return -EINVAL;
+ }
+ iter->bi_idx--;
+ iter->bi_bvec_done = __bvec_iter_bvec(bv, *iter)->bv_len;
+ continue;
+ }
+ bytes -= len;
+ iter->bi_size += len;
+ iter->bi_bvec_done -= len;
+ }
+ return 0;
+}
+
#define for_each_bvec(bvl, bio_vec, iter, start) \
for (iter = (start); \
(iter).bi_size && \
--
2.9.3
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[PATCH 0/9] block: T10/DIF Fixes and cleanups v3 Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
[PATCH 4/9] bio-integrity: fix interface for bio_integrity_trim v2 Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 4/9] bio-integrity: fix interface for bio_integrity_trim v2 Hannes Reinecke <hare@suse.de> - 2017-04-05 08:40 +0200
Re: [PATCH 4/9] bio-integrity: fix interface for bio_integrity_trim v2 Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:40 +0200
[PATCH 8/9] bio: add bvec_iter rewind API Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 8/9] bio: add bvec_iter rewind API Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:50 +0200
[PATCH 2/9] bio-integrity: bio_trim should truncate integrity vector accordingly Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 2/9] bio-integrity: bio_trim should truncate integrity vector accordingly Hannes Reinecke <hare@suse.de> - 2017-04-05 08:40 +0200
[PATCH 6/9] T10: Move opencoded contants to common header Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 6/9] T10: Move opencoded contants to common header Hannes Reinecke <hare@suse.de> - 2017-04-05 08:40 +0200
Re: [PATCH 6/9] T10: Move opencoded contants to common header Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:50 +0200
[PATCH 1/9] bio-integrity: Do not allocate integrity context for bio w/o data Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
[PATCH 5/9] bio-integrity: fold bio_integrity_enabled to bio_integrity_prep Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 5/9] bio-integrity: fold bio_integrity_enabled to bio_integrity_prep Hannes Reinecke <hare@suse.de> - 2017-04-05 08:40 +0200
Re: [PATCH 5/9] bio-integrity: fold bio_integrity_enabled to bio_integrity_prep Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:50 +0200
[PATCH 9/9] bio-integrity: Restore original iterator on verify stage Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 9/9] bio-integrity: Restore original iterator on verify stage Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:50 +0200
[PATCH 3/9] bio-integrity: bio_integrity_advance must update integrity seed Dmitry Monakhov <dmonakhov@openvz.org> - 2017-04-04 21:00 +0200
Re: [PATCH 3/9] bio-integrity: bio_integrity_advance must update integrity seed Hannes Reinecke <hare@suse.de> - 2017-04-05 08:40 +0200
Re: [PATCH 3/9] bio-integrity: bio_integrity_advance must update integrity seed Christoph Hellwig <hch@infradead.org> - 2017-04-06 13:40 +0200
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