From: Kent Overstreet <koverstreet@google.com>
To: axboe@kernel.dk, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, dm-devel@vger.kernel.org
Cc: tj@kernel.org, neilb@suse.de,
Kent Overstreet <koverstreet@google.com>,
Lars Ellenberg <drbd-dev@lists.linbit.com>,
Paul Clements <Paul.Clements@steeleye.com>,
drbd-user@lists.linbit.com, nbd-general@lists.sourceforge.net
Subject: [PATCH 05/22] block: Immutable bio vecs
Date: Wed, 27 Mar 2013 10:39:35 -0700 [thread overview]
Message-ID: <1364405992-28424-6-git-send-email-koverstreet@google.com> (raw)
In-Reply-To: <1364405992-28424-1-git-send-email-koverstreet@google.com>
This adds a mechanism by which we can advance a bio by an arbitrary
number of bytes without modifying the biovec: bio->bi_iter.bi_bvec_done
indicates the number of bytes completed in the current bvec.
Various driver code still needs to be updated to not refer to the bvec
directly before we can use this for interesting things, like efficient
bio splitting.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Cc: drbd-user@lists.linbit.com
Cc: nbd-general@lists.sourceforge.net
---
drivers/block/drbd/drbd_main.c | 4 +-
drivers/block/nbd.c | 2 +-
fs/bio.c | 23 +--------
include/linux/bio.h | 108 ++++++++++++++++++++++++++++++++---------
include/linux/blk_types.h | 2 +
include/linux/blkdev.h | 4 +-
6 files changed, 94 insertions(+), 49 deletions(-)
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index e90074c..b3c013e 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1546,7 +1546,7 @@ static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
err = _drbd_no_send_page(mdev, bvec.bv_page,
bvec.bv_offset, bvec.bv_len,
- bio_iter_last(bio, iter)
+ bio_iter_last(bvec, iter)
? 0 : MSG_MORE);
if (err)
return err;
@@ -1565,7 +1565,7 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
err = _drbd_send_page(mdev, bvec.bv_page,
bvec.bv_offset, bvec.bv_len,
- bio_iter_last(bio, iter) ? 0 : MSG_MORE);
+ bio_iter_last(bvec, iter) ? 0 : MSG_MORE);
if (err)
return err;
}
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index c426d18..6c01425 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -278,7 +278,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)
*/
rq_for_each_segment(bvec, req, iter) {
flags = 0;
- if (!rq_iter_last(req, iter))
+ if (!rq_iter_last(bvec, iter))
flags = MSG_MORE;
dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
nbd->disk->disk_name, req, bvec.bv_len);
diff --git a/fs/bio.c b/fs/bio.c
index 400f90c..cb89a59 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -807,28 +807,7 @@ void bio_advance(struct bio *bio, unsigned bytes)
if (bio_integrity(bio))
bio_integrity_advance(bio, bytes);
- bio->bi_iter.bi_sector += bytes >> 9;
- bio->bi_iter.bi_size -= bytes;
-
- if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
- return;
-
- while (bytes) {
- if (unlikely(bio->bi_iter.bi_idx >= bio->bi_vcnt)) {
- WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
- bio->bi_iter.bi_idx, bio->bi_vcnt);
- break;
- }
-
- if (bytes >= bio_iovec(bio).bv_len) {
- bytes -= bio_iovec(bio).bv_len;
- bio->bi_iter.bi_idx++;
- } else {
- bio_iovec(bio).bv_len -= bytes;
- bio_iovec(bio).bv_offset += bytes;
- bytes = 0;
- }
- }
+ bio_advance_iter(bio, &bio->bi_iter, bytes);
}
EXPORT_SYMBOL(bio_advance);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index a31bcd2..3c194bc 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -61,21 +61,58 @@
* various member access, note that bio_data should of course not be used
* on highmem page vectors
*/
-#define bio_iovec_iter(bio, iter) ((bio)->bi_io_vec[(iter).bi_idx])
-
#define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
#define __bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_iter.bi_idx)
-#define bio_iovec(bio) (*__bio_iovec(bio))
-#define bio_page(bio) (bio_iovec((bio)).bv_page)
-#define bio_offset(bio) (bio_iovec((bio)).bv_offset)
+#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
+
+#define bvec_iter_page(bvec, iter) \
+ (__bvec_iter_bvec((bvec), (iter))->bv_page)
+#define bvec_iter_len(bio, iter) \
+ min((iter).bi_size, \
+ __bvec_iter_bvec((bio), (iter))->bv_len - (iter).bi_bvec_done)
+#define bvec_iter_offset(bio, iter) \
+ (__bvec_iter_bvec((bio), (iter))->bv_offset + (iter).bi_bvec_done)
+
+#define bvec_iter_bvec(bvec, iter) \
+((struct bio_vec) { \
+ .bv_page = bvec_iter_page((bvec), (iter)), \
+ .bv_len = bvec_iter_len((bvec), (iter)), \
+ .bv_offset = bvec_iter_offset((bvec), (iter)), \
+})
+
+
+#define bio_iovec_iter(bio, iter) \
+ bvec_iter_bvec((bio)->bi_io_vec, (iter))
+#define bio_page_iter(bio, iter) \
+ bvec_iter_page((bio)->bi_io_vec, (iter))
+#define bio_offset_iter(bio, iter) \
+ bvec_iter_offset((bio)->bi_io_vec, (iter))
+
+#define bio_page(bio) bio_page_iter((bio), (bio)->bi_iter)
+#define bio_offset(bio) bio_offset_iter((bio), (bio)->bi_iter)
+#define bio_iovec(bio) bio_iovec_iter((bio), (bio)->bi_iter)
+
#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_iter.bi_idx)
#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 & BIO_NO_ADVANCE_ITER_MASK))
+ return true;
+
+ return false;
+}
+
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;
@@ -83,7 +120,7 @@ static inline unsigned int bio_cur_bytes(struct bio *bio)
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;
@@ -144,16 +181,54 @@ static inline void *bio_data(struct bio *bio)
bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt; \
i++)
+static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
+ unsigned bytes)
+{
+ WARN_ONCE(bytes > iter->bi_size,
+ "Attempted to advance past end of bvec iter\n");
+
+ while (bytes) {
+ unsigned len = min(bytes, bvec_iter_len(bv, *iter));
+
+ bytes -= len;
+ iter->bi_size -= len;
+ iter->bi_bvec_done += len;
+
+ if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
+ iter->bi_bvec_done = 0;
+ iter->bi_idx++;
+ }
+ }
+}
+
+#define for_each_bvec(bvl, bio_vec, iter, start) \
+ for ((iter) = start; \
+ (bvl) = bvec_iter_bvec((bio_vec), (iter)), \
+ (iter).bi_size; \
+ bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
+
+
+static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
+ unsigned bytes)
+{
+ iter->bi_sector += bytes >> 9;
+
+ if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
+ iter->bi_size -= bytes;
+ else
+ bvec_iter_advance(bio->bi_io_vec, iter, bytes);
+}
+
#define __bio_for_each_segment(bvl, bio, iter, start) \
for (iter = (start); \
- bvl = bio_iovec_iter((bio), (iter)), \
- (iter).bi_idx < (bio)->bi_vcnt; \
- (iter).bi_idx++)
+ (iter).bi_size && \
+ ((bvl = bio_iovec_iter((bio), (iter))), 1); \
+ bio_advance_iter((bio), &(iter), (bvl).bv_len))
#define bio_for_each_segment(bvl, bio, iter) \
__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
-#define bio_iter_last(bio, iter) ((iter).bi_idx == (bio)->bi_vcnt - 1)
+#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
/*
* get a reference to a bio, so it won't disappear. the intended use is
@@ -368,17 +443,6 @@ static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
__bio_kmap_irq((bio), (bio)->bi_iter.bi_idx, (flags))
#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))
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 66bf67a..495a025 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -34,6 +34,8 @@ struct bvec_iter {
unsigned int bi_size; /* residual I/O count */
unsigned int bi_idx; /* current index into bvl_vec */
+
+ unsigned int bi_bvec_done;
};
/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f589ed3..870a347 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -714,9 +714,9 @@ struct req_iterator {
__rq_for_each_bio(_iter.bio, _rq) \
bio_for_each_segment(bvl, _iter.bio, _iter.iter)
-#define rq_iter_last(rq, _iter) \
+#define rq_iter_last(bvec, _iter) \
(_iter.bio->bi_next == NULL && \
- bio_iter_last(_iter.bio, _iter.iter))
+ bio_iter_last(bvec, _iter.iter))
#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
--
1.8.1.3
next prev parent reply other threads:[~2013-03-27 17:47 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-27 17:39 Immutable biovecs Kent Overstreet
2013-03-27 17:39 ` [PATCH 01/22] block: Abstract out bvec iterator Kent Overstreet
2013-03-27 17:39 ` [PATCH 02/22] dm: Use bvec_iter for dm_bio_record() Kent Overstreet
2013-03-27 17:39 ` [PATCH 03/22] block: Convert bio_iovec() to bvec_iter Kent Overstreet
2013-03-27 17:39 ` Kent Overstreet [this message]
2013-03-27 17:39 ` [PATCH 06/22] aoe: Convert " Kent Overstreet
2013-03-27 17:39 ` [PATCH 07/22] dm-verity: convert to bvec iter Kent Overstreet
2013-03-27 17:39 ` [PATCH 08/22] block: Convert bio_copy_data() to bvec_iter Kent Overstreet
2013-03-27 17:39 ` [PATCH 09/22] bio-integrity: Convert " Kent Overstreet
2013-03-27 17:39 ` [PATCH 10/22] dm-crypt: " Kent Overstreet
2013-03-27 17:39 ` [PATCH 11/22] dm-io: Convert DM_IO_BVEC -> DM_IO_BIO Kent Overstreet
2013-03-27 17:39 ` [PATCH 12/22] umem: Convert to bvec_iter Kent Overstreet
2013-03-27 17:39 ` [PATCH 13/22] ceph: " Kent Overstreet
2013-03-27 17:39 ` [PATCH 14/22] block: Kill __BVEC_END, __BVEC_START Kent Overstreet
2013-03-27 17:39 ` [PATCH 15/22] block: Kill bio_iovec_idx(), __bio_iovec() Kent Overstreet
2013-03-27 17:39 ` [PATCH 16/22] rbd: Refactor bio cloning, don't clone biovecs Kent Overstreet
2013-03-27 17:39 ` [PATCH 17/22] dm: Refactor for new bio cloning/splitting Kent Overstreet
2013-03-27 17:39 ` [PATCH 18/22] block: Kill bio_sector_offset() Kent Overstreet
2013-03-27 17:39 ` [PATCH 19/22] md: Immutable bvecs Kent Overstreet
2013-03-27 17:39 ` [PATCH 20/22] dm: Don't save bvec anymore Kent Overstreet
2013-03-27 17:39 ` [PATCH 21/22] block: Don't save bvec in bio_map_data Kent Overstreet
2013-03-27 17:39 ` [PATCH 22/22] block: Don't copy bvecs when cloning bios, just share them Kent Overstreet
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