[PATCH 00/27] Block cleanups - prep work for immutable bio vecs/dio rewrite

[PATCH 00/27] Block cleanups - prep work for immutable bio vecs/dio rewrite

[Kent Overstreet]

Jens - this is the patch series I was working on a couple months ago,
and then got sidetracked on.

I rebased it onto your for-3.9/core branch. Nothing's changed (besides a
few random merge conflicts) since the last time I mailed it out - I
think all this stuff is ready.


Kent Overstreet (27):
  block: Reorder struct bio_set
  block: Avoid deadlocks with bio allocation by stacking drivers
  block: Fix a buffer overrun in bio_integrity_split()
  block: Convert integrity to bvec_alloc_bs()
  block: Add bio_advance()
  block: Refactor blk_update_request()
  md: Convert md_trim_bio() to use bio_advance()
  block: Add bio_end_sector()
  block: Use bio_sectors() more consistently
  block: Change bio_split() to respect the current value of bi_idx
  block: Remove bi_idx references
  block: Remove some unnecessary bi_vcnt usage
  block: Add submit_bio_wait(), remove from md
  raid10: Use bio_reset()
  raid1: use bio_reset()
  raid5: use bio_reset()
  raid1: Refactor narrow_write_error() to not use bi_idx
  block: Add bio_copy_data()
  pktcdvd: use bio_copy_data()
  pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage
  raid1: use bio_copy_data()
  bounce: Refactor __blk_queue_bounce to not use bi_io_vec
  block: Add bio_for_each_segment_all()
  block: Convert some code to bio_for_each_segment_all()
  block: Add bio_alloc_pages()
  block: Add an explicit bio flag for bios that own their bvec
  bio-integrity: Add explicit field for owner of bip_buf

 block/blk-core.c                         |  82 ++-----
 block/cfq-iosched.c                      |   7 +-
 block/deadline-iosched.c                 |   2 +-
 drivers/block/aoe/aoecmd.c               |   2 +-
 drivers/block/brd.c                      |   3 +-
 drivers/block/floppy.c                   |   1 -
 drivers/block/pktcdvd.c                  | 102 ++-------
 drivers/block/rbd.c                      |   2 +-
 drivers/md/dm-crypt.c                    |   3 +-
 drivers/md/dm-raid1.c                    |   2 +-
 drivers/md/dm-stripe.c                   |   2 +-
 drivers/md/dm-verity.c                   |   4 +-
 drivers/md/faulty.c                      |   6 +-
 drivers/md/linear.c                      |   3 +-
 drivers/md/md.c                          |  17 +-
 drivers/md/raid0.c                       |   9 +-
 drivers/md/raid1.c                       | 133 ++++-------
 drivers/md/raid10.c                      |  78 ++-----
 drivers/md/raid5.c                       |  49 ++---
 drivers/message/fusion/mptsas.c          |   6 +-
 drivers/s390/block/dcssblk.c             |   3 +-
 drivers/scsi/libsas/sas_expander.c       |   6 +-
 drivers/scsi/mpt2sas/mpt2sas_transport.c |  10 +-
 fs/bio-integrity.c                       | 144 +++++-------
 fs/bio.c                                 | 366 +++++++++++++++++++++++++++----
 fs/btrfs/extent_io.c                     |   3 +-
 fs/btrfs/volumes.c                       |   2 +-
 fs/buffer.c                              |   1 -
 fs/direct-io.c                           |   8 +-
 fs/exofs/ore.c                           |   2 +-
 fs/exofs/ore_raid.c                      |   2 +-
 fs/gfs2/lops.c                           |   2 +-
 fs/jfs/jfs_logmgr.c                      |   2 -
 fs/logfs/dev_bdev.c                      |   5 -
 include/linux/bio.h                      | 115 ++++++----
 include/linux/blk_types.h                |   3 +
 include/trace/events/block.h             |  12 +-
 mm/bounce.c                              |  75 ++-----
 mm/page_io.c                             |   1 -
 39 files changed, 645 insertions(+), 630 deletions(-)

-- 
1.7.12

[PATCH 01/27] block: Reorder struct bio_set

[Kent Overstreet]

This is prep work for the next patch, which embeds a struct bio_list in
struct bio_set.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 include/linux/bio.h | 66 ++++++++++++++++++++++++++---------------------------
 1 file changed, 33 insertions(+), 33 deletions(-)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 820e7aa..93d3d17 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -298,39 +298,6 @@ static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 static inline void bio_disassociate_task(struct bio *bio) { }
 #endif	/* CONFIG_BLK_CGROUP */
 
-/*
- * bio_set is used to allow other portions of the IO system to
- * allocate their own private memory pools for bio and iovec structures.
- * These memory pools in turn all allocate from the bio_slab
- * and the bvec_slabs[].
- */
-#define BIO_POOL_SIZE 2
-#define BIOVEC_NR_POOLS 6
-#define BIOVEC_MAX_IDX	(BIOVEC_NR_POOLS - 1)
-
-struct bio_set {
-	struct kmem_cache *bio_slab;
-	unsigned int front_pad;
-
-	mempool_t *bio_pool;
-#if defined(CONFIG_BLK_DEV_INTEGRITY)
-	mempool_t *bio_integrity_pool;
-#endif
-	mempool_t *bvec_pool;
-};
-
-struct biovec_slab {
-	int nr_vecs;
-	char *name;
-	struct kmem_cache *slab;
-};
-
-/*
- * a small number of entries is fine, not going to be performance critical.
- * basically we just need to survive
- */
-#define BIO_SPLIT_ENTRIES 2
-
 #ifdef CONFIG_HIGHMEM
 /*
  * remember never ever reenable interrupts between a bvec_kmap_irq and
@@ -527,6 +494,39 @@ static inline struct bio *bio_list_get(struct bio_list *bl)
 	return bio;
 }
 
+/*
+ * bio_set is used to allow other portions of the IO system to
+ * allocate their own private memory pools for bio and iovec structures.
+ * These memory pools in turn all allocate from the bio_slab
+ * and the bvec_slabs[].
+ */
+#define BIO_POOL_SIZE 2
+#define BIOVEC_NR_POOLS 6
+#define BIOVEC_MAX_IDX	(BIOVEC_NR_POOLS - 1)
+
+struct bio_set {
+	struct kmem_cache *bio_slab;
+	unsigned int front_pad;
+
+	mempool_t *bio_pool;
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+	mempool_t *bio_integrity_pool;
+#endif
+	mempool_t *bvec_pool;
+};
+
+struct biovec_slab {
+	int nr_vecs;
+	char *name;
+	struct kmem_cache *slab;
+};
+
+/*
+ * a small number of entries is fine, not going to be performance critical.
+ * basically we just need to survive
+ */
+#define BIO_SPLIT_ENTRIES 2
+
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 
 #define bip_vec_idx(bip, idx)	(&(bip->bip_vec[(idx)]))
-- 
1.7.12

[PATCH 02/27] block: Avoid deadlocks with bio allocation by stacking drivers

[Kent Overstreet]

Previously, if we ever try to allocate more than once from the same bio
set while running under generic_make_request() (i.e. a stacking block
driver), we risk deadlock.

This is because of the code in generic_make_request() that converts
recursion to iteration; any bios we submit won't actually be submitted
(so they can complete and eventually be freed) until after we return -
this means if we allocate a second bio, we're blocking the first one
from ever being freed.

Thus if enough threads call into a stacking block driver at the same
time with bios that need multiple splits, and the bio_set's reserve gets
used up, we deadlock.

This can be worked around in the driver code - we could check if we're
running under generic_make_request(), then mask out __GFP_WAIT when we
go to allocate a bio, and if the allocation fails punt to workqueue and
retry the allocation.

But this is tricky and not a generic solution. This patch solves it for
all users by inverting the previously described technique. We allocate a
rescuer workqueue for each bio_set, and then in the allocation code if
there are bios on current->bio_list we would be blocking, we punt them
to the rescuer workqueue to be submitted.

This guarantees forward progress for bio allocations under
generic_make_request() provided each bio is submitted before allocating
the next, and provided the bios are freed after they complete.

Note that this doesn't do anything for allocation from other mempools.
Instead of allocating per bio data structures from a mempool, code
should use bio_set's front_pad.

Tested it by forcing the rescue codepath to be taken (by disabling the
first GFP_NOWAIT) attempt, and then ran it with bcache (which does a lot
of arbitrary bio splitting) and verified that the rescuer was being
invoked.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Muthukumar Ratty <muthur@gmail.com>
---
 fs/bio.c            | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/bio.h |   9 ++++
 2 files changed, 123 insertions(+), 2 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index bb5768f..73b5447 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -297,6 +297,54 @@ void bio_reset(struct bio *bio)
 }
 EXPORT_SYMBOL(bio_reset);
 
+static void bio_alloc_rescue(struct work_struct *work)
+{
+	struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
+	struct bio *bio;
+
+	while (1) {
+		spin_lock(&bs->rescue_lock);
+		bio = bio_list_pop(&bs->rescue_list);
+		spin_unlock(&bs->rescue_lock);
+
+		if (!bio)
+			break;
+
+		generic_make_request(bio);
+	}
+}
+
+static void punt_bios_to_rescuer(struct bio_set *bs)
+{
+	struct bio_list punt, nopunt;
+	struct bio *bio;
+
+	/*
+	 * In order to guarantee forward progress we must punt only bios that
+	 * were allocated from this bio_set; otherwise, if there was a bio on
+	 * there for a stacking driver higher up in the stack, processing it
+	 * could require allocating bios from this bio_set, and doing that from
+	 * our own rescuer would be bad.
+	 *
+	 * Since bio lists are singly linked, pop them all instead of trying to
+	 * remove from the middle of the list:
+	 */
+
+	bio_list_init(&punt);
+	bio_list_init(&nopunt);
+
+	while ((bio = bio_list_pop(current->bio_list)))
+		bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
+
+	*current->bio_list = nopunt;
+
+	spin_lock(&bs->rescue_lock);
+	bio_list_merge(&bs->rescue_list, &punt);
+	spin_unlock(&bs->rescue_lock);
+
+	queue_work(bs->rescue_workqueue, &bs->rescue_work);
+}
+
 /**
  * bio_alloc_bioset - allocate a bio for I/O
  * @gfp_mask:   the GFP_ mask given to the slab allocator
@@ -314,11 +362,27 @@ EXPORT_SYMBOL(bio_reset);
  *   previously allocated bio for IO before attempting to allocate a new one.
  *   Failure to do so can cause deadlocks under memory pressure.
  *
+ *   Note that when running under generic_make_request() (i.e. any block
+ *   driver), bios are not submitted until after you return - see the code in
+ *   generic_make_request() that converts recursion into iteration, to prevent
+ *   stack overflows.
+ *
+ *   This would normally mean allocating multiple bios under
+ *   generic_make_request() would be susceptible to deadlocks, but we have
+ *   deadlock avoidance code that resubmits any blocked bios from a rescuer
+ *   thread.
+ *
+ *   However, we do not guarantee forward progress for allocations from other
+ *   mempools. Doing multiple allocations from the same mempool under
+ *   generic_make_request() should be avoided - instead, use bio_set's front_pad
+ *   for per bio allocations.
+ *
  *   RETURNS:
  *   Pointer to new bio on success, NULL on failure.
  */
 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 {
+	gfp_t saved_gfp = gfp_mask;
 	unsigned front_pad;
 	unsigned inline_vecs;
 	unsigned long idx = BIO_POOL_NONE;
@@ -336,7 +400,37 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 		front_pad = 0;
 		inline_vecs = nr_iovecs;
 	} else {
+		/*
+		 * generic_make_request() converts recursion to iteration; this
+		 * means if we're running beneath it, any bios we allocate and
+		 * submit will not be submitted (and thus freed) until after we
+		 * return.
+		 *
+		 * This exposes us to a potential deadlock if we allocate
+		 * multiple bios from the same bio_set() while running
+		 * underneath generic_make_request(). If we were to allocate
+		 * multiple bios (say a stacking block driver that was splitting
+		 * bios), we would deadlock if we exhausted the mempool's
+		 * reserve.
+		 *
+		 * We solve this, and guarantee forward progress, with a rescuer
+		 * workqueue per bio_set. If we go to allocate and there are
+		 * bios on current->bio_list, we first try the allocation
+		 * without __GFP_WAIT; if that fails, we punt those bios we
+		 * would be blocking to the rescuer workqueue before we retry
+		 * with the original gfp_flags.
+		 */
+
+		if (current->bio_list && !bio_list_empty(current->bio_list))
+			gfp_mask &= ~__GFP_WAIT;
+
 		p = mempool_alloc(bs->bio_pool, gfp_mask);
+		if (!p && gfp_mask != saved_gfp) {
+			punt_bios_to_rescuer(bs);
+			gfp_mask = saved_gfp;
+			p = mempool_alloc(bs->bio_pool, gfp_mask);
+		}
+
 		front_pad = bs->front_pad;
 		inline_vecs = BIO_INLINE_VECS;
 	}
@@ -349,6 +443,12 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 
 	if (nr_iovecs > inline_vecs) {
 		bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
+		if (!bvl && gfp_mask != saved_gfp) {
+			punt_bios_to_rescuer(bs);
+			gfp_mask = saved_gfp;
+			bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
+		}
+
 		if (unlikely(!bvl))
 			goto err_free;
 	} else if (nr_iovecs) {
@@ -1579,6 +1679,9 @@ static void biovec_free_pools(struct bio_set *bs)
 
 void bioset_free(struct bio_set *bs)
 {
+	if (bs->rescue_workqueue)
+		destroy_workqueue(bs->rescue_workqueue);
+
 	if (bs->bio_pool)
 		mempool_destroy(bs->bio_pool);
 
@@ -1614,6 +1717,10 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
 
 	bs->front_pad = front_pad;
 
+	spin_lock_init(&bs->rescue_lock);
+	bio_list_init(&bs->rescue_list);
+	INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
+
 	bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
 	if (!bs->bio_slab) {
 		kfree(bs);
@@ -1624,9 +1731,14 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
 	if (!bs->bio_pool)
 		goto bad;
 
-	if (!biovec_create_pools(bs, pool_size))
-		return bs;
+	if (biovec_create_pools(bs, pool_size))
+		goto bad;
+
+	bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
+	if (!bs->rescue_workqueue)
+		goto bad;
 
+	return bs;
 bad:
 	bioset_free(bs);
 	return NULL;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 93d3d17..b31036f 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -513,6 +513,15 @@ struct bio_set {
 	mempool_t *bio_integrity_pool;
 #endif
 	mempool_t *bvec_pool;
+
+	/*
+	 * Deadlock avoidance for stacking block drivers: see comments in
+	 * bio_alloc_bioset() for details
+	 */
+	spinlock_t		rescue_lock;
+	struct bio_list		rescue_list;
+	struct work_struct	rescue_work;
+	struct workqueue_struct	*rescue_workqueue;
 };
 
 struct biovec_slab {
-- 
1.7.12

[PATCH 03/27] block: Fix a buffer overrun in bio_integrity_split()

[Kent Overstreet]

bio_integrity_split() seemed to be confusing pointers and arrays -
bip_vec in bio_integrity_payload was an array appended to the end of the
payload, so the bio_vecs in struct bio_pair should have come after the
bio_integrity_payload they're for.

Fix it by making bip_vec a pointer to the inline vecs - a later patch is
going to make more use of this pointer.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
---
 fs/bio-integrity.c  | 5 +++--
 include/linux/bio.h | 4 +++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index a3f28f3..94fa1c5 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -112,6 +112,7 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 
 	bip->bip_slab = idx;
 	bip->bip_bio = bio;
+	bip->bip_vec = bip->bip_inline_vecs;
 	bio->bi_integrity = bip;
 
 	return bip;
@@ -697,8 +698,8 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
 	bp->iv1 = bip->bip_vec[0];
 	bp->iv2 = bip->bip_vec[0];
 
-	bp->bip1.bip_vec[0] = bp->iv1;
-	bp->bip2.bip_vec[0] = bp->iv2;
+	bp->bip1.bip_vec = &bp->iv1;
+	bp->bip2.bip_vec = &bp->iv2;
 
 	bp->iv1.bv_len = sectors * bi->tuple_size;
 	bp->iv2.bv_offset += sectors * bi->tuple_size;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b31036f..81004fd 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -182,7 +182,9 @@ struct bio_integrity_payload {
 	unsigned short		bip_idx;	/* current bip_vec index */
 
 	struct work_struct	bip_work;	/* I/O completion */
-	struct bio_vec		bip_vec[0];	/* embedded bvec array */
+
+	struct bio_vec		*bip_vec;
+	struct bio_vec		bip_inline_vecs[0];/* embedded bvec array */
 };
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
-- 
1.7.12

[PATCH 04/27] block: Convert integrity to bvec_alloc_bs()

[Kent Overstreet]

This adds a pointer to the bvec array to struct bio_integrity_payload,
instead of the bvecs always being inline; then the bvecs are allocated
with bvec_alloc_bs().

Changed bvec_alloc_bs() and bvec_free_bs() to take a pointer to a
mempool instead of the bioset, so that bio integrity can use a different
mempool for its bvecs, and thus avoid a potential deadlock.

This is eventually for immutable bio vecs - immutable bvecs aren't
useful if we still have to copy them, hence the need for the pointer.
Less code is always nice too, though.

Also, bio_integrity_alloc() was using fs_bio_set if no bio_set was
specified. This was wrong - using the bio_set doesn't protect us from
memory allocation failures, because we just used kmalloc for the
bio_integrity_payload. But it does introduce the possibility of
deadlock, if for some reason we weren't supposed to be using fs_bio_set.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
---
 fs/bio-integrity.c  | 132 +++++++++++++++++++---------------------------------
 fs/bio.c            |  36 ++++++--------
 include/linux/bio.h |   8 ++--
 3 files changed, 68 insertions(+), 108 deletions(-)

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 94fa1c5..8c4c604 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -27,48 +27,11 @@
 #include <linux/workqueue.h>
 #include <linux/slab.h>
 
-struct integrity_slab {
-	struct kmem_cache *slab;
-	unsigned short nr_vecs;
-	char name[8];
-};
-
-#define IS(x) { .nr_vecs = x, .name = "bip-"__stringify(x) }
-struct integrity_slab bip_slab[BIOVEC_NR_POOLS] __read_mostly = {
-	IS(1), IS(4), IS(16), IS(64), IS(128), IS(BIO_MAX_PAGES),
-};
-#undef IS
+#define BIP_INLINE_VECS	4
 
+static struct kmem_cache *bip_slab;
 static struct workqueue_struct *kintegrityd_wq;
 
-static inline unsigned int vecs_to_idx(unsigned int nr)
-{
-	switch (nr) {
-	case 1:
-		return 0;
-	case 2 ... 4:
-		return 1;
-	case 5 ... 16:
-		return 2;
-	case 17 ... 64:
-		return 3;
-	case 65 ... 128:
-		return 4;
-	case 129 ... BIO_MAX_PAGES:
-		return 5;
-	default:
-		BUG();
-	}
-}
-
-static inline int use_bip_pool(unsigned int idx)
-{
-	if (idx == BIOVEC_MAX_IDX)
-		return 1;
-
-	return 0;
-}
-
 /**
  * bio_integrity_alloc - Allocate integrity payload and attach it to bio
  * @bio:	bio to attach integrity metadata to
@@ -84,38 +47,41 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
 						  unsigned int nr_vecs)
 {
 	struct bio_integrity_payload *bip;
-	unsigned int idx = vecs_to_idx(nr_vecs);
 	struct bio_set *bs = bio->bi_pool;
-
-	if (!bs)
-		bs = fs_bio_set;
-
-	BUG_ON(bio == NULL);
-	bip = NULL;
-
-	/* Lower order allocations come straight from slab */
-	if (!use_bip_pool(idx))
-		bip = kmem_cache_alloc(bip_slab[idx].slab, gfp_mask);
-
-	/* Use mempool if lower order alloc failed or max vecs were requested */
-	if (bip == NULL) {
-		idx = BIOVEC_MAX_IDX;  /* so we free the payload properly later */
+	unsigned long idx = BIO_POOL_NONE;
+	unsigned inline_vecs;
+
+	if (!bs) {
+		bip = kmalloc(sizeof(struct bio_integrity_payload) +
+			      sizeof(struct bio_vec) * nr_vecs, gfp_mask);
+		inline_vecs = nr_vecs;
+	} else {
 		bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
-
-		if (unlikely(bip == NULL)) {
-			printk(KERN_ERR "%s: could not alloc bip\n", __func__);
-			return NULL;
-		}
+		inline_vecs = BIP_INLINE_VECS;
 	}
 
+	if (unlikely(!bip))
+		return NULL;
+
 	memset(bip, 0, sizeof(*bip));
 
+	if (nr_vecs > inline_vecs) {
+		bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
+					  bs->bvec_integrity_pool);
+		if (!bip->bip_vec)
+			goto err;
+	} else {
+		bip->bip_vec = bip->bip_inline_vecs;
+	}
+
 	bip->bip_slab = idx;
 	bip->bip_bio = bio;
-	bip->bip_vec = bip->bip_inline_vecs;
 	bio->bi_integrity = bip;
 
 	return bip;
+err:
+	mempool_free(bip, bs->bio_integrity_pool);
+	return NULL;
 }
 EXPORT_SYMBOL(bio_integrity_alloc);
 
@@ -131,20 +97,20 @@ void bio_integrity_free(struct bio *bio)
 	struct bio_integrity_payload *bip = bio->bi_integrity;
 	struct bio_set *bs = bio->bi_pool;
 
-	if (!bs)
-		bs = fs_bio_set;
-
-	BUG_ON(bip == NULL);
-
 	/* A cloned bio doesn't own the integrity metadata */
 	if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
 	    && bip->bip_buf != NULL)
 		kfree(bip->bip_buf);
 
-	if (use_bip_pool(bip->bip_slab))
+	if (bs) {
+		if (bip->bip_slab != BIO_POOL_NONE)
+			bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
+				  bip->bip_slab);
+
 		mempool_free(bip, bs->bio_integrity_pool);
-	else
-		kmem_cache_free(bip_slab[bip->bip_slab].slab, bip);
+	} else {
+		kfree(bip);
+	}
 
 	bio->bi_integrity = NULL;
 }
@@ -747,13 +713,14 @@ EXPORT_SYMBOL(bio_integrity_clone);
 
 int bioset_integrity_create(struct bio_set *bs, int pool_size)
 {
-	unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
-
 	if (bs->bio_integrity_pool)
 		return 0;
 
-	bs->bio_integrity_pool =
-		mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
+	bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
+
+	bs->bvec_integrity_pool = biovec_create_pool(bs, pool_size);
+	if (!bs->bvec_integrity_pool)
+		return -1;
 
 	if (!bs->bio_integrity_pool)
 		return -1;
@@ -766,13 +733,14 @@ void bioset_integrity_free(struct bio_set *bs)
 {
 	if (bs->bio_integrity_pool)
 		mempool_destroy(bs->bio_integrity_pool);
+
+	if (bs->bvec_integrity_pool)
+		mempool_destroy(bs->bio_integrity_pool);
 }
 EXPORT_SYMBOL(bioset_integrity_free);
 
 void __init bio_integrity_init(void)
 {
-	unsigned int i;
-
 	/*
 	 * kintegrityd won't block much but may burn a lot of CPU cycles.
 	 * Make it highpri CPU intensive wq with max concurrency of 1.
@@ -782,14 +750,10 @@ void __init bio_integrity_init(void)
 	if (!kintegrityd_wq)
 		panic("Failed to create kintegrityd\n");
 
-	for (i = 0 ; i < BIOVEC_NR_POOLS ; i++) {
-		unsigned int size;
-
-		size = sizeof(struct bio_integrity_payload)
-			+ bip_slab[i].nr_vecs * sizeof(struct bio_vec);
-
-		bip_slab[i].slab =
-			kmem_cache_create(bip_slab[i].name, size, 0,
-					  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
-	}
+	bip_slab = kmem_cache_create("bio_integrity_payload",
+				     sizeof(struct bio_integrity_payload) +
+				     sizeof(struct bio_vec) * BIP_INLINE_VECS,
+				     0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+	if (!bip_slab)
+		panic("Failed to create slab\n");
 }
diff --git a/fs/bio.c b/fs/bio.c
index 73b5447..40aa96e 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -160,12 +160,12 @@ unsigned int bvec_nr_vecs(unsigned short idx)
 	return bvec_slabs[idx].nr_vecs;
 }
 
-void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
+void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
 {
 	BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
 
 	if (idx == BIOVEC_MAX_IDX)
-		mempool_free(bv, bs->bvec_pool);
+		mempool_free(bv, pool);
 	else {
 		struct biovec_slab *bvs = bvec_slabs + idx;
 
@@ -173,8 +173,8 @@ void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
 	}
 }
 
-struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
-			      struct bio_set *bs)
+struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
+			   mempool_t *pool)
 {
 	struct bio_vec *bvl;
 
@@ -210,7 +210,7 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
 	 */
 	if (*idx == BIOVEC_MAX_IDX) {
 fallback:
-		bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
+		bvl = mempool_alloc(pool, gfp_mask);
 	} else {
 		struct biovec_slab *bvs = bvec_slabs + *idx;
 		gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
@@ -253,7 +253,7 @@ static void bio_free(struct bio *bio)
 
 	if (bs) {
 		if (bio_has_allocated_vec(bio))
-			bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
+			bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
 
 		/*
 		 * If we have front padding, adjust the bio pointer before freeing
@@ -442,11 +442,11 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 	bio_init(bio);
 
 	if (nr_iovecs > inline_vecs) {
-		bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
+		bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
 		if (!bvl && gfp_mask != saved_gfp) {
 			punt_bios_to_rescuer(bs);
 			gfp_mask = saved_gfp;
-			bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
+			bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
 		}
 
 		if (unlikely(!bvl))
@@ -1661,20 +1661,11 @@ EXPORT_SYMBOL(bio_sector_offset);
  * create memory pools for biovec's in a bio_set.
  * use the global biovec slabs created for general use.
  */
-static int biovec_create_pools(struct bio_set *bs, int pool_entries)
+mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
 {
 	struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
 
-	bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
-	if (!bs->bvec_pool)
-		return -ENOMEM;
-
-	return 0;
-}
-
-static void biovec_free_pools(struct bio_set *bs)
-{
-	mempool_destroy(bs->bvec_pool);
+	return mempool_create_slab_pool(pool_entries, bp->slab);
 }
 
 void bioset_free(struct bio_set *bs)
@@ -1685,8 +1676,10 @@ void bioset_free(struct bio_set *bs)
 	if (bs->bio_pool)
 		mempool_destroy(bs->bio_pool);
 
+	if (bs->bvec_pool)
+		mempool_destroy(bs->bvec_pool);
+
 	bioset_integrity_free(bs);
-	biovec_free_pools(bs);
 	bio_put_slab(bs);
 
 	kfree(bs);
@@ -1731,7 +1724,8 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
 	if (!bs->bio_pool)
 		goto bad;
 
-	if (biovec_create_pools(bs, pool_size))
+	bs->bvec_pool = biovec_create_pool(bs, pool_size);
+	if (!bs->bvec_pool)
 		goto bad;
 
 	bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 81004fd..669b1cb 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -213,6 +213,7 @@ extern void bio_pair_release(struct bio_pair *dbio);
 
 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 extern void bioset_free(struct bio_set *);
+extern mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries);
 
 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 extern void bio_put(struct bio *);
@@ -288,8 +289,8 @@ extern struct bio *bio_copy_user_iov(struct request_queue *,
 				     int, int, gfp_t);
 extern int bio_uncopy_user(struct bio *);
 void zero_fill_bio(struct bio *bio);
-extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
-extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
+extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
+extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 extern unsigned int bvec_nr_vecs(unsigned short idx);
 
 #ifdef CONFIG_BLK_CGROUP
@@ -511,10 +512,11 @@ struct bio_set {
 	unsigned int front_pad;
 
 	mempool_t *bio_pool;
+	mempool_t *bvec_pool;
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 	mempool_t *bio_integrity_pool;
+	mempool_t *bvec_integrity_pool;
 #endif
-	mempool_t *bvec_pool;
 
 	/*
 	 * Deadlock avoidance for stacking block drivers: see comments in
-- 
1.7.12

[PATCH 05/27] block: Add bio_advance()

[Kent Overstreet]

This is prep work for immutable bio vecs; we first want to centralize
where bvecs are modified.

Next two patches convert some existing code to use this function.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 fs/bio.c                  | 41 +++++++++++++++++++++++++++++++++++++++++
 include/linux/bio.h       |  2 ++
 include/linux/blk_types.h |  2 ++
 3 files changed, 45 insertions(+)

diff --git a/fs/bio.c b/fs/bio.c
index 40aa96e..7edc08d 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -752,6 +752,47 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
 }
 EXPORT_SYMBOL(bio_add_page);
 
+/**
+ * bio_advance - increment/complete a bio by some number of bytes
+ * @bio:	bio to advance
+ * @bytes:	number of bytes to complete
+ *
+ * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
+ * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
+ * be updated on the last bvec as well.
+ *
+ * @bio will then represent the remaining, uncompleted portion of the io.
+ */
+void bio_advance(struct bio *bio, unsigned bytes)
+{
+	if (bio_integrity(bio))
+		bio_integrity_advance(bio, bytes);
+
+	bio->bi_sector += bytes >> 9;
+	bio->bi_size -= bytes;
+
+	if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
+		return;
+
+	while (bytes) {
+		if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
+			WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
+				  bio->bi_idx, bio->bi_vcnt);
+			break;
+		}
+
+		if (bytes >= bio_iovec(bio)->bv_len) {
+			bytes -= bio_iovec(bio)->bv_len;
+			bio->bi_idx++;
+		} else {
+			bio_iovec(bio)->bv_len -= bytes;
+			bio_iovec(bio)->bv_offset += bytes;
+			bytes = 0;
+		}
+	}
+}
+EXPORT_SYMBOL(bio_advance);
+
 struct bio_map_data {
 	struct bio_vec *iovecs;
 	struct sg_iovec *sgvecs;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 669b1cb..fcb4dba 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -248,6 +248,8 @@ extern void bio_endio(struct bio *, int);
 struct request_queue;
 extern int bio_phys_segments(struct request_queue *, struct bio *);
 
+extern void bio_advance(struct bio *, unsigned);
+
 extern void bio_init(struct bio *);
 extern void bio_reset(struct bio *);
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index cdf1119..c178d25 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -197,6 +197,8 @@ enum rq_flag_bits {
 	 REQ_SECURE)
 #define REQ_CLONE_MASK		REQ_COMMON_MASK
 
+#define BIO_NO_ADVANCE_ITER_MASK	(REQ_DISCARD|REQ_WRITE_SAME)
+
 /* This mask is used for both bio and request merge checking */
 #define REQ_NOMERGE_FLAGS \
 	(REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
-- 
1.7.12

[PATCH 06/27] block: Refactor blk_update_request()

[Kent Overstreet]

Converts it to use bio_advance(), simplifying it quite a bit in the
process.

Note that req_bio_endio() now always calls bio_advance() - which means
it always loops over the biovec, not just on partial completions. Don't
expect it to affect performance, but worth noting.

Tested it by forcing partial updates, and dumping before and after on
various bio/bvec fields when doing a partial update.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 block/blk-core.c | 80 +++++++++-----------------------------------------------
 1 file changed, 12 insertions(+), 68 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 66d3168..8f9f19b 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -158,20 +158,10 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
 	else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
 		error = -EIO;
 
-	if (unlikely(nbytes > bio->bi_size)) {
-		printk(KERN_ERR "%s: want %u bytes done, %u left\n",
-		       __func__, nbytes, bio->bi_size);
-		nbytes = bio->bi_size;
-	}
-
 	if (unlikely(rq->cmd_flags & REQ_QUIET))
 		set_bit(BIO_QUIET, &bio->bi_flags);
 
-	bio->bi_size -= nbytes;
-	bio->bi_sector += (nbytes >> 9);
-
-	if (bio_integrity(bio))
-		bio_integrity_advance(bio, nbytes);
+	bio_advance(bio, nbytes);
 
 	/* don't actually finish bio if it's part of flush sequence */
 	if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
@@ -2250,8 +2240,7 @@ EXPORT_SYMBOL(blk_fetch_request);
  **/
 bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 {
-	int total_bytes, bio_nbytes, next_idx = 0;
-	struct bio *bio;
+	int total_bytes;
 
 	if (!req->bio)
 		return false;
@@ -2297,56 +2286,21 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 
 	blk_account_io_completion(req, nr_bytes);
 
-	total_bytes = bio_nbytes = 0;
-	while ((bio = req->bio) != NULL) {
-		int nbytes;
+	total_bytes = 0;
+	while (req->bio) {
+		struct bio *bio = req->bio;
+		unsigned bio_bytes = min(bio->bi_size, nr_bytes);
 
-		if (nr_bytes >= bio->bi_size) {
+		if (bio_bytes == bio->bi_size)
 			req->bio = bio->bi_next;
-			nbytes = bio->bi_size;
-			req_bio_endio(req, bio, nbytes, error);
-			next_idx = 0;
-			bio_nbytes = 0;
-		} else {
-			int idx = bio->bi_idx + next_idx;
-
-			if (unlikely(idx >= bio->bi_vcnt)) {
-				blk_dump_rq_flags(req, "__end_that");
-				printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
-				       __func__, idx, bio->bi_vcnt);
-				break;
-			}
-
-			nbytes = bio_iovec_idx(bio, idx)->bv_len;
-			BIO_BUG_ON(nbytes > bio->bi_size);
-
-			/*
-			 * not a complete bvec done
-			 */
-			if (unlikely(nbytes > nr_bytes)) {
-				bio_nbytes += nr_bytes;
-				total_bytes += nr_bytes;
-				break;
-			}
 
-			/*
-			 * advance to the next vector
-			 */
-			next_idx++;
-			bio_nbytes += nbytes;
-		}
+		req_bio_endio(req, bio, bio_bytes, error);
 
-		total_bytes += nbytes;
-		nr_bytes -= nbytes;
+		total_bytes += bio_bytes;
+		nr_bytes -= bio_bytes;
 
-		bio = req->bio;
-		if (bio) {
-			/*
-			 * end more in this run, or just return 'not-done'
-			 */
-			if (unlikely(nr_bytes <= 0))
-				break;
-		}
+		if (!nr_bytes)
+			break;
 	}
 
 	/*
@@ -2362,16 +2316,6 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 		return false;
 	}
 
-	/*
-	 * if the request wasn't completed, update state
-	 */
-	if (bio_nbytes) {
-		req_bio_endio(req, bio, bio_nbytes, error);
-		bio->bi_idx += next_idx;
-		bio_iovec(bio)->bv_offset += nr_bytes;
-		bio_iovec(bio)->bv_len -= nr_bytes;
-	}
-
 	req->__data_len -= total_bytes;
 	req->buffer = bio_data(req->bio);
 
-- 
1.7.12

[PATCH 07/27] md: Convert md_trim_bio() to use bio_advance()

[Kent Overstreet]

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: NeilBrown <neilb@suse.de>
---
 drivers/md/md.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3db3d1b..cfd0a5d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -194,21 +194,12 @@ void md_trim_bio(struct bio *bio, int offset, int size)
 	if (offset == 0 && size == bio->bi_size)
 		return;
 
-	bio->bi_sector += offset;
-	bio->bi_size = size;
-	offset <<= 9;
 	clear_bit(BIO_SEG_VALID, &bio->bi_flags);
 
-	while (bio->bi_idx < bio->bi_vcnt &&
-	       bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
-		/* remove this whole bio_vec */
-		offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
-		bio->bi_idx++;
-	}
-	if (bio->bi_idx < bio->bi_vcnt) {
-		bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
-		bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
-	}
+	bio_advance(bio, offset << 9);
+
+	bio->bi_size = size;
+
 	/* avoid any complications with bi_idx being non-zero*/
 	if (bio->bi_idx) {
 		memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
-- 
1.7.12

[PATCH 08/27] block: Add bio_end_sector()

[Kent Overstreet]

Just a little convenience macro - main reason to add it now is preparing
for immutable bio vecs, it'll reduce the size of the patch that puts
bi_sector/bi_size/bi_idx into a struct bvec_iter.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Lars Ellenberg <drbd-dev@lists.linbit.com>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Neil Brown <neilb@suse.de>
CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
CC: Heiko Carstens <heiko.carstens@de.ibm.com>
CC: linux-s390@vger.kernel.org
CC: Chris Mason <chris.mason@fusionio.com>
CC: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
---
 block/blk-core.c             |  2 +-
 block/cfq-iosched.c          |  7 ++-----
 block/deadline-iosched.c     |  2 +-
 drivers/block/brd.c          |  3 +--
 drivers/block/pktcdvd.c      |  6 +++---
 drivers/md/dm-stripe.c       |  2 +-
 drivers/md/dm-verity.c       |  2 +-
 drivers/md/faulty.c          |  6 ++----
 drivers/md/linear.c          |  3 +--
 drivers/md/raid1.c           |  4 ++--
 drivers/md/raid5.c           | 14 +++++++-------
 drivers/s390/block/dcssblk.c |  3 +--
 fs/btrfs/extent_io.c         |  3 +--
 fs/gfs2/lops.c               |  2 +-
 include/linux/bio.h          |  1 +
 15 files changed, 26 insertions(+), 34 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 8f9f19b..9a285f4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1581,7 +1581,7 @@ static void handle_bad_sector(struct bio *bio)
 	printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
 			bdevname(bio->bi_bdev, b),
 			bio->bi_rw,
-			(unsigned long long)bio->bi_sector + bio_sectors(bio),
+			(unsigned long long)bio_end_sector(bio),
 			(long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
 
 	set_bit(BIO_EOF, &bio->bi_flags);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b66365b..83b8c88 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2271,11 +2271,8 @@ cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
 		return NULL;
 
 	cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
-	if (cfqq) {
-		sector_t sector = bio->bi_sector + bio_sectors(bio);
-
-		return elv_rb_find(&cfqq->sort_list, sector);
-	}
+	if (cfqq)
+		return elv_rb_find(&cfqq->sort_list, bio_end_sector(bio));
 
 	return NULL;
 }
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 90037b5..ba19a3a 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -132,7 +132,7 @@ deadline_merge(struct request_queue *q, struct request **req, struct bio *bio)
 	 * check for front merge
 	 */
 	if (dd->front_merges) {
-		sector_t sector = bio->bi_sector + bio_sectors(bio);
+		sector_t sector = bio_end_sector(bio);
 
 		__rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector);
 		if (__rq) {
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 531ceb3..f1a29f8 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -334,8 +334,7 @@ static void brd_make_request(struct request_queue *q, struct bio *bio)
 	int err = -EIO;
 
 	sector = bio->bi_sector;
-	if (sector + (bio->bi_size >> SECTOR_SHIFT) >
-						get_capacity(bdev->bd_disk))
+	if (bio_end_sector(bio) > get_capacity(bdev->bd_disk))
 		goto out;
 
 	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 2e7de7a..26938e8 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -901,7 +901,7 @@ static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
 			pd->iosched.successive_reads += bio->bi_size >> 10;
 		else {
 			pd->iosched.successive_reads = 0;
-			pd->iosched.last_write = bio->bi_sector + bio_sectors(bio);
+			pd->iosched.last_write = bio_end_sector(bio);
 		}
 		if (pd->iosched.successive_reads >= HI_SPEED_SWITCH) {
 			if (pd->read_speed == pd->write_speed) {
@@ -2454,7 +2454,7 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
 	zone = ZONE(bio->bi_sector, pd);
 	VPRINTK("pkt_make_request: start = %6llx stop = %6llx\n",
 		(unsigned long long)bio->bi_sector,
-		(unsigned long long)(bio->bi_sector + bio_sectors(bio)));
+		(unsigned long long)bio_end_sector(bio));
 
 	/* Check if we have to split the bio */
 	{
@@ -2462,7 +2462,7 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
 		sector_t last_zone;
 		int first_sectors;
 
-		last_zone = ZONE(bio->bi_sector + bio_sectors(bio) - 1, pd);
+		last_zone = ZONE(bio_end_sector(bio) - 1, pd);
 		if (last_zone != zone) {
 			BUG_ON(last_zone != zone + pd->settings.size);
 			first_sectors = last_zone - bio->bi_sector;
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index c89cde86..c6ec571 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -258,7 +258,7 @@ static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
 	sector_t begin, end;
 
 	stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin);
-	stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio),
+	stripe_map_range_sector(sc, bio_end_sector(bio),
 				target_stripe, &end);
 	if (begin < end) {
 		bio->bi_bdev = sc->stripe[target_stripe].dev->bdev;
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 52cde98..03d6d21 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -472,7 +472,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 		return -EIO;
 	}
 
-	if ((bio->bi_sector + bio_sectors(bio)) >>
+	if (bio_end_sector(bio) >>
 	    (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) {
 		DMERR_LIMIT("io out of range");
 		return -EIO;
diff --git a/drivers/md/faulty.c b/drivers/md/faulty.c
index 5e7dc77..3193aef 100644
--- a/drivers/md/faulty.c
+++ b/drivers/md/faulty.c
@@ -185,8 +185,7 @@ static void make_request(struct mddev *mddev, struct bio *bio)
 			return;
 		}
 
-		if (check_sector(conf, bio->bi_sector, bio->bi_sector+(bio->bi_size>>9),
-				 WRITE))
+		if (check_sector(conf, bio->bi_sector, bio_end_sector(bio), WRITE))
 			failit = 1;
 		if (check_mode(conf, WritePersistent)) {
 			add_sector(conf, bio->bi_sector, WritePersistent);
@@ -196,8 +195,7 @@ static void make_request(struct mddev *mddev, struct bio *bio)
 			failit = 1;
 	} else {
 		/* read request */
-		if (check_sector(conf, bio->bi_sector, bio->bi_sector + (bio->bi_size>>9),
-				 READ))
+		if (check_sector(conf, bio->bi_sector, bio_end_sector(bio), READ))
 			failit = 1;
 		if (check_mode(conf, ReadTransient))
 			failit = 1;
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 2101483..f03fabd 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -317,8 +317,7 @@ static void linear_make_request(struct mddev *mddev, struct bio *bio)
 		bio_io_error(bio);
 		return;
 	}
-	if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
-		     tmp_dev->end_sector)) {
+	if (unlikely(bio_end_sector(bio) > tmp_dev->end_sector)) {
 		/* This bio crosses a device boundary, so we have to
 		 * split it.
 		 */
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d5bddfc..2117622 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1016,7 +1016,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 	md_write_start(mddev, bio); /* wait on superblock update early */
 
 	if (bio_data_dir(bio) == WRITE &&
-	    bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
+	    bio_end_sector(bio) > mddev->suspend_lo &&
 	    bio->bi_sector < mddev->suspend_hi) {
 		/* As the suspend_* range is controlled by
 		 * userspace, we want an interruptible
@@ -1027,7 +1027,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 			flush_signals(current);
 			prepare_to_wait(&conf->wait_barrier,
 					&w, TASK_INTERRUPTIBLE);
-			if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
+			if (bio_end_sector(bio) <= mddev->suspend_lo ||
 			    bio->bi_sector >= mddev->suspend_hi)
 				break;
 			schedule();
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9ab506d..a203039 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2421,11 +2421,11 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
 	} else
 		bip = &sh->dev[dd_idx].toread;
 	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
-		if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
+		if (bio_end_sector(*bip) > bi->bi_sector)
 			goto overlap;
 		bip = & (*bip)->bi_next;
 	}
-	if (*bip && (*bip)->bi_sector < bi->bi_sector + ((bi->bi_size)>>9))
+	if (*bip && (*bip)->bi_sector < bio_end_sector(bi))
 		goto overlap;
 
 	BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
@@ -2441,8 +2441,8 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
 		     sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
 			     bi && bi->bi_sector <= sector;
 		     bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
-			if (bi->bi_sector + (bi->bi_size>>9) >= sector)
-				sector = bi->bi_sector + (bi->bi_size>>9);
+			if (bio_end_sector(bi) >= sector)
+				sector = bio_end_sector(bi);
 		}
 		if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
 			set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags);
@@ -3978,7 +3978,7 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
 						    0,
 						    &dd_idx, NULL);
 
-	end_sector = align_bi->bi_sector + (align_bi->bi_size >> 9);
+	end_sector = bio_end_sector(align_bi);
 	rcu_read_lock();
 	rdev = rcu_dereference(conf->disks[dd_idx].replacement);
 	if (!rdev || test_bit(Faulty, &rdev->flags) ||
@@ -4253,7 +4253,7 @@ static void make_request(struct mddev *mddev, struct bio * bi)
 	}
 
 	logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
-	last_sector = bi->bi_sector + (bi->bi_size>>9);
+	last_sector = bio_end_sector(bi);
 	bi->bi_next = NULL;
 	bi->bi_phys_segments = 1;	/* over-loaded to count active stripes */
 
@@ -4716,7 +4716,7 @@ static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio)
 	logical_sector = raid_bio->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
 	sector = raid5_compute_sector(conf, logical_sector,
 				      0, &dd_idx, NULL);
-	last_sector = raid_bio->bi_sector + (raid_bio->bi_size>>9);
+	last_sector = bio_end_sector(raid_bio);
 
 	for (; logical_sector < last_sector;
 	     logical_sector += STRIPE_SECTORS,
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index b6ad0de..12d08b4 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -826,8 +826,7 @@ dcssblk_make_request(struct request_queue *q, struct bio *bio)
 	if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 		/* Request is not page-aligned. */
 		goto fail;
-	if (((bio->bi_size >> 9) + bio->bi_sector)
-			> get_capacity(bio->bi_bdev->bd_disk)) {
+	if (bio_end_sector(bio) > get_capacity(bio->bi_bdev->bd_disk)) {
 		/* Request beyond end of DCSS segment. */
 		goto fail;
 	}
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1b319df..a291f44 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2526,8 +2526,7 @@ static int submit_extent_page(int rw, struct extent_io_tree *tree,
 		if (old_compressed)
 			contig = bio->bi_sector == sector;
 		else
-			contig = bio->bi_sector + (bio->bi_size >> 9) ==
-				sector;
+			contig = bio_end_sector(bio) == sector;
 
 		if (prev_bio_flags != bio_flags || !contig ||
 		    merge_bio(tree, page, offset, page_size, bio, bio_flags) ||
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 9ceccb1..ada9c6a 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -300,7 +300,7 @@ static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno)
 	u64 nblk;
 
 	if (bio) {
-		nblk = bio->bi_sector + bio_sectors(bio);
+		nblk = bio_end_sector(bio);
 		nblk >>= sdp->sd_fsb2bb_shift;
 		if (blkno == nblk)
 			return bio;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index fcb4dba..20507eb 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -67,6 +67,7 @@
 #define bio_offset(bio)		bio_iovec((bio))->bv_offset
 #define bio_segments(bio)	((bio)->bi_vcnt - (bio)->bi_idx)
 #define bio_sectors(bio)	((bio)->bi_size >> 9)
+#define bio_end_sector(bio)	((bio)->bi_sector + bio_sectors((bio)))
 
 static inline unsigned int bio_cur_bytes(struct bio *bio)
 {
-- 
1.7.12

[PATCH 09/27] block: Use bio_sectors() more consistently

[Kent Overstreet]

Bunch of places in the code weren't using it where they could be -
this'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx
into a struct bvec_iter.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: "Ed L. Cashin" <ecashin@coraid.com>
CC: Nick Piggin <npiggin@kernel.dk>
CC: Jiri Kosina <jkosina@suse.cz>
CC: Jim Paris <jim@jtan.com>
CC: Geoff Levand <geoff@infradead.org>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Neil Brown <neilb@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Ed Cashin <ecashin@coraid.com>
---
 drivers/block/pktcdvd.c      |  2 +-
 drivers/md/dm-raid1.c        |  2 +-
 drivers/md/raid0.c           |  6 +++---
 drivers/md/raid1.c           | 17 ++++++++---------
 drivers/md/raid10.c          | 24 +++++++++++-------------
 drivers/md/raid5.c           |  8 ++++----
 fs/btrfs/volumes.c           |  2 +-
 include/trace/events/block.h | 12 ++++++------
 8 files changed, 35 insertions(+), 38 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 26938e8..2c27744 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2433,7 +2433,7 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
 		cloned_bio->bi_bdev = pd->bdev;
 		cloned_bio->bi_private = psd;
 		cloned_bio->bi_end_io = pkt_end_io_read_cloned;
-		pd->stats.secs_r += bio->bi_size >> 9;
+		pd->stats.secs_r += bio_sectors(bio);
 		pkt_queue_bio(pd, cloned_bio);
 		return;
 	}
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index fa51918..b61ed2b 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -455,7 +455,7 @@ static void map_region(struct dm_io_region *io, struct mirror *m,
 {
 	io->bdev = m->dev->bdev;
 	io->sector = map_sector(m, bio);
-	io->count = bio->bi_size >> 9;
+	io->count = bio_sectors(bio);
 }
 
 static void hold_bio(struct mirror_set *ms, struct bio *bio)
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 24b3597..1ff39e6 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -495,11 +495,11 @@ static inline int is_io_in_chunk_boundary(struct mddev *mddev,
 {
 	if (likely(is_power_of_2(chunk_sects))) {
 		return chunk_sects >= ((bio->bi_sector & (chunk_sects-1))
-					+ (bio->bi_size >> 9));
+					+ bio_sectors(bio));
 	} else{
 		sector_t sector = bio->bi_sector;
 		return chunk_sects >= (sector_div(sector, chunk_sects)
-						+ (bio->bi_size >> 9));
+						+ bio_sectors(bio));
 	}
 }
 
@@ -560,7 +560,7 @@ bad_map:
 	printk("md/raid0:%s: make_request bug: can't convert block across chunks"
 	       " or bigger than %dk %llu %d\n",
 	       mdname(mddev), chunk_sects / 2,
-	       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
+	       (unsigned long long)bio->bi_sector, bio_sectors(bio) / 2);
 
 	bio_io_error(bio);
 	return;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 2117622..b47503b 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -267,7 +267,7 @@ static void raid_end_bio_io(struct r1bio *r1_bio)
 			 (bio_data_dir(bio) == WRITE) ? "write" : "read",
 			 (unsigned long long) bio->bi_sector,
 			 (unsigned long long) bio->bi_sector +
-			 (bio->bi_size >> 9) - 1);
+			 bio_sectors(bio) - 1);
 
 		call_bio_endio(r1_bio);
 	}
@@ -458,7 +458,7 @@ static void raid1_end_write_request(struct bio *bio, int error)
 					 " %llu-%llu\n",
 					 (unsigned long long) mbio->bi_sector,
 					 (unsigned long long) mbio->bi_sector +
-					 (mbio->bi_size >> 9) - 1);
+					 bio_sectors(mbio) - 1);
 				call_bio_endio(r1_bio);
 			}
 		}
@@ -1047,7 +1047,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 	r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 
 	r1_bio->master_bio = bio;
-	r1_bio->sectors = bio->bi_size >> 9;
+	r1_bio->sectors = bio_sectors(bio);
 	r1_bio->state = 0;
 	r1_bio->mddev = mddev;
 	r1_bio->sector = bio->bi_sector;
@@ -1125,7 +1125,7 @@ read_again:
 			r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 
 			r1_bio->master_bio = bio;
-			r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
+			r1_bio->sectors = bio_sectors(bio) - sectors_handled;
 			r1_bio->state = 0;
 			r1_bio->mddev = mddev;
 			r1_bio->sector = bio->bi_sector + sectors_handled;
@@ -1326,14 +1326,14 @@ read_again:
 	/* Mustn't call r1_bio_write_done before this next test,
 	 * as it could result in the bio being freed.
 	 */
-	if (sectors_handled < (bio->bi_size >> 9)) {
+	if (sectors_handled < bio_sectors(bio)) {
 		r1_bio_write_done(r1_bio);
 		/* We need another r1_bio.  It has already been counted
 		 * in bio->bi_phys_segments
 		 */
 		r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 		r1_bio->master_bio = bio;
-		r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
+		r1_bio->sectors = bio_sectors(bio) - sectors_handled;
 		r1_bio->state = 0;
 		r1_bio->mddev = mddev;
 		r1_bio->sector = bio->bi_sector + sectors_handled;
@@ -1944,7 +1944,7 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
 		wbio->bi_rw = WRITE;
 		wbio->bi_end_io = end_sync_write;
 		atomic_inc(&r1_bio->remaining);
-		md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
+		md_sync_acct(conf->mirrors[i].rdev->bdev, bio_sectors(wbio));
 
 		generic_make_request(wbio);
 	}
@@ -2281,8 +2281,7 @@ read_more:
 			r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
 
 			r1_bio->master_bio = mbio;
-			r1_bio->sectors = (mbio->bi_size >> 9)
-					  - sectors_handled;
+			r1_bio->sectors = bio_sectors(mbio) - sectors_handled;
 			r1_bio->state = 0;
 			set_bit(R1BIO_ReadError, &r1_bio->state);
 			r1_bio->mddev = mddev;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 64d4824..4c6705f 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1121,7 +1121,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 	/* If this request crosses a chunk boundary, we need to
 	 * split it.  This will only happen for 1 PAGE (or less) requests.
 	 */
-	if (unlikely((bio->bi_sector & chunk_mask) + (bio->bi_size >> 9)
+	if (unlikely((bio->bi_sector & chunk_mask) + bio_sectors(bio)
 		     > chunk_sects
 		     && (conf->geo.near_copies < conf->geo.raid_disks
 			 || conf->prev.near_copies < conf->prev.raid_disks))) {
@@ -1161,7 +1161,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 	bad_map:
 		printk("md/raid10:%s: make_request bug: can't convert block across chunks"
 		       " or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
-		       (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
+		       (unsigned long long)bio->bi_sector, bio_sectors(bio) / 2);
 
 		bio_io_error(bio);
 		return;
@@ -1176,7 +1176,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 	 */
 	wait_barrier(conf);
 
-	sectors = bio->bi_size >> 9;
+	sectors = bio_sectors(bio);
 	while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
 	    bio->bi_sector < conf->reshape_progress &&
 	    bio->bi_sector + sectors > conf->reshape_progress) {
@@ -1278,8 +1278,7 @@ read_again:
 			r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
 			r10_bio->master_bio = bio;
-			r10_bio->sectors = ((bio->bi_size >> 9)
-					    - sectors_handled);
+			r10_bio->sectors = bio_sectors(bio) - sectors_handled;
 			r10_bio->state = 0;
 			r10_bio->mddev = mddev;
 			r10_bio->sector = bio->bi_sector + sectors_handled;
@@ -1519,7 +1518,7 @@ retry_write:
 	 * after checking if we need to go around again.
 	 */
 
-	if (sectors_handled < (bio->bi_size >> 9)) {
+	if (sectors_handled < bio_sectors(bio)) {
 		one_write_done(r10_bio);
 		/* We need another r10_bio.  It has already been counted
 		 * in bio->bi_phys_segments.
@@ -1527,7 +1526,7 @@ retry_write:
 		r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
 		r10_bio->master_bio = bio;
-		r10_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
+		r10_bio->sectors = bio_sectors(bio) - sectors_handled;
 
 		r10_bio->mddev = mddev;
 		r10_bio->sector = bio->bi_sector + sectors_handled;
@@ -2053,7 +2052,7 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 		d = r10_bio->devs[i].devnum;
 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
 		atomic_inc(&r10_bio->remaining);
-		md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
+		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
 
 		tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
 		tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
@@ -2078,7 +2077,7 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 		d = r10_bio->devs[i].devnum;
 		atomic_inc(&r10_bio->remaining);
 		md_sync_acct(conf->mirrors[d].replacement->bdev,
-			     tbio->bi_size >> 9);
+			     bio_sectors(tbio));
 		generic_make_request(tbio);
 	}
 
@@ -2204,13 +2203,13 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 	wbio2 = r10_bio->devs[1].repl_bio;
 	if (wbio->bi_end_io) {
 		atomic_inc(&conf->mirrors[d].rdev->nr_pending);
-		md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
+		md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
 		generic_make_request(wbio);
 	}
 	if (wbio2 && wbio2->bi_end_io) {
 		atomic_inc(&conf->mirrors[d].replacement->nr_pending);
 		md_sync_acct(conf->mirrors[d].replacement->bdev,
-			     wbio2->bi_size >> 9);
+			     bio_sectors(wbio2));
 		generic_make_request(wbio2);
 	}
 }
@@ -2640,8 +2639,7 @@ read_more:
 		r10_bio = mempool_alloc(conf->r10bio_pool,
 					GFP_NOIO);
 		r10_bio->master_bio = mbio;
-		r10_bio->sectors = (mbio->bi_size >> 9)
-			- sectors_handled;
+		r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
 		r10_bio->state = 0;
 		set_bit(R10BIO_ReadError,
 			&r10_bio->state);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a203039..0ba12c3 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -90,7 +90,7 @@ static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  */
 static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
 {
-	int sectors = bio->bi_size >> 9;
+	int sectors = bio_sectors(bio);
 	if (bio->bi_sector + sectors < sector + STRIPE_SECTORS)
 		return bio->bi_next;
 	else
@@ -3841,7 +3841,7 @@ static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
 {
 	sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
 	unsigned int chunk_sectors = mddev->chunk_sectors;
-	unsigned int bio_sectors = bio->bi_size >> 9;
+	unsigned int bio_sectors = bio_sectors(bio);
 
 	if (mddev->new_chunk_sectors < mddev->chunk_sectors)
 		chunk_sectors = mddev->new_chunk_sectors;
@@ -3931,7 +3931,7 @@ static int bio_fits_rdev(struct bio *bi)
 {
 	struct request_queue *q = bdev_get_queue(bi->bi_bdev);
 
-	if ((bi->bi_size>>9) > queue_max_sectors(q))
+	if (bio_sectors(bi) > queue_max_sectors(q))
 		return 0;
 	blk_recount_segments(q, bi);
 	if (bi->bi_phys_segments > queue_max_segments(q))
@@ -4001,7 +4001,7 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio)
 		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);
 
 		if (!bio_fits_rdev(align_bi) ||
-		    is_badblock(rdev, align_bi->bi_sector, align_bi->bi_size>>9,
+		    is_badblock(rdev, align_bi->bi_sector, bio_sectors(align_bi),
 				&first_bad, &bad_sectors)) {
 			/* too big in some way, or has a known bad block */
 			bio_put(align_bi);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5cce6aa..07ff012 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4722,7 +4722,7 @@ static int bio_size_ok(struct block_device *bdev, struct bio *bio,
 	}
 
 	prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
-	if ((bio->bi_size >> 9) > max_sectors)
+	if (bio_sectors(bio) > max_sectors)
 		return 0;
 
 	if (!q->merge_bvec_fn)
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 9961726..5a28843 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -244,7 +244,7 @@ TRACE_EVENT(block_bio_bounce,
 		__entry->dev		= bio->bi_bdev ?
 					  bio->bi_bdev->bd_dev : 0;
 		__entry->sector		= bio->bi_sector;
-		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->nr_sector	= bio_sectors(bio);
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
 		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
 	),
@@ -281,7 +281,7 @@ TRACE_EVENT(block_bio_complete,
 		__entry->dev		= bio->bi_bdev ?
 					  bio->bi_bdev->bd_dev : 0;
 		__entry->sector		= bio->bi_sector;
-		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->nr_sector	= bio_sectors(bio);
 		__entry->error		= error;
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
 	),
@@ -309,7 +309,7 @@ DECLARE_EVENT_CLASS(block_bio_merge,
 	TP_fast_assign(
 		__entry->dev		= bio->bi_bdev->bd_dev;
 		__entry->sector		= bio->bi_sector;
-		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->nr_sector	= bio_sectors(bio);
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
 		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
 	),
@@ -376,7 +376,7 @@ TRACE_EVENT(block_bio_queue,
 	TP_fast_assign(
 		__entry->dev		= bio->bi_bdev->bd_dev;
 		__entry->sector		= bio->bi_sector;
-		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->nr_sector	= bio_sectors(bio);
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
 		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
 	),
@@ -404,7 +404,7 @@ DECLARE_EVENT_CLASS(block_get_rq,
 	TP_fast_assign(
 		__entry->dev		= bio ? bio->bi_bdev->bd_dev : 0;
 		__entry->sector		= bio ? bio->bi_sector : 0;
-		__entry->nr_sector	= bio ? bio->bi_size >> 9 : 0;
+		__entry->nr_sector	= bio ? bio_sectors(bio) : 0;
 		blk_fill_rwbs(__entry->rwbs,
 			      bio ? bio->bi_rw : 0, __entry->nr_sector);
 		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
@@ -580,7 +580,7 @@ TRACE_EVENT(block_bio_remap,
 	TP_fast_assign(
 		__entry->dev		= bio->bi_bdev->bd_dev;
 		__entry->sector		= bio->bi_sector;
-		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->nr_sector	= bio_sectors(bio);
 		__entry->old_dev	= dev;
 		__entry->old_sector	= from;
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
-- 
1.7.12

[PATCH 10/27] block: Change bio_split() to respect the current value of bi_idx

[Kent Overstreet]

In the current code bio_split() won't be seeing partially completed bios
so this doesn't change any behaviour, but this makes the code a bit
clearer as to what bio_split() actually requires.

The immediate purpose of the patch is removing unnecessary bi_idx
references, but the end goal is to allow partial completed bios to be
submitted, which along with immutable biovecs enables effecient bio
splitting.

Some of the callers were (double) checking that bios could be split, so
update their checks too.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Lars Ellenberg <drbd-dev@lists.linbit.com>
CC: Neil Brown <neilb@suse.de>
CC: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/md/raid0.c  | 3 +--
 drivers/md/raid10.c | 3 +--
 fs/bio-integrity.c  | 4 ++--
 fs/bio.c            | 7 +++----
 4 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 1ff39e6..0a07239 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -520,8 +520,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
 		sector_t sector = bio->bi_sector;
 		struct bio_pair *bp;
 		/* Sanity check -- queue functions should prevent this happening */
-		if ((bio->bi_vcnt != 1 && bio->bi_vcnt != 0) ||
-		    bio->bi_idx != 0)
+		if (bio_segments(bio) > 1)
 			goto bad_map;
 		/* This is a one page bio that upper layers
 		 * refuse to split for us, so we need to split it.
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 4c6705f..84cd9d7 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1127,8 +1127,7 @@ static void make_request(struct mddev *mddev, struct bio * bio)
 			 || conf->prev.near_copies < conf->prev.raid_disks))) {
 		struct bio_pair *bp;
 		/* Sanity check -- queue functions should prevent this happening */
-		if ((bio->bi_vcnt != 1 && bio->bi_vcnt != 0) ||
-		    bio->bi_idx != 0)
+		if (bio_segments(bio) > 1)
 			goto bad_map;
 		/* This is a one page bio that upper layers
 		 * refuse to split for us, so we need to split it.
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 8c4c604..ca7b02d 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -661,8 +661,8 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
 	bp->bio1.bi_integrity = &bp->bip1;
 	bp->bio2.bi_integrity = &bp->bip2;
 
-	bp->iv1 = bip->bip_vec[0];
-	bp->iv2 = bip->bip_vec[0];
+	bp->iv1 = bip->bip_vec[bip->bip_idx];
+	bp->iv2 = bip->bip_vec[bip->bip_idx];
 
 	bp->bip1.bip_vec = &bp->iv1;
 	bp->bip2.bip_vec = &bp->iv2;
diff --git a/fs/bio.c b/fs/bio.c
index 7edc08d..f1b4c16 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1620,8 +1620,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
 	trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
 				bi->bi_sector + first_sectors);
 
-	BUG_ON(bi->bi_vcnt != 1 && bi->bi_vcnt != 0);
-	BUG_ON(bi->bi_idx != 0);
+	BUG_ON(bio_segments(bi) > 1);
 	atomic_set(&bp->cnt, 3);
 	bp->error = 0;
 	bp->bio1 = *bi;
@@ -1631,8 +1630,8 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
 	bp->bio1.bi_size = first_sectors << 9;
 
 	if (bi->bi_vcnt != 0) {
-		bp->bv1 = bi->bi_io_vec[0];
-		bp->bv2 = bi->bi_io_vec[0];
+		bp->bv1 = *bio_iovec(bi);
+		bp->bv2 = *bio_iovec(bi);
 
 		if (bio_is_rw(bi)) {
 			bp->bv2.bv_offset += first_sectors << 9;
-- 
1.7.12

[PATCH 11/27] block: Remove bi_idx references

[Kent Overstreet]

For immutable bvecs, all bi_idx usage needs to be audited - so here
we're removing all the unnecessary uses.

Most of these are places where it was being initialized on a bio that
was just allocated, a few others are conversions to standard macros.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 drivers/block/aoe/aoecmd.c | 2 +-
 drivers/block/floppy.c     | 1 -
 drivers/md/dm-verity.c     | 2 +-
 drivers/md/raid10.c        | 1 -
 fs/buffer.c                | 1 -
 fs/jfs/jfs_logmgr.c        | 2 --
 fs/logfs/dev_bdev.c        | 5 -----
 mm/page_io.c               | 1 -
 8 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 25ef5c0..8188ad1 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -927,7 +927,7 @@ bufinit(struct buf *buf, struct request *rq, struct bio *bio)
 	buf->resid = bio->bi_size;
 	buf->sector = bio->bi_sector;
 	bio_pageinc(bio);
-	buf->bv = bv = &bio->bi_io_vec[bio->bi_idx];
+	buf->bv = bio_iovec(bio);
 	buf->bv_resid = bv->bv_len;
 	WARN_ON(buf->bv_resid == 0);
 }
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 2ddd64a..8323263 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3777,7 +3777,6 @@ static int __floppy_read_block_0(struct block_device *bdev)
 	bio_vec.bv_len = size;
 	bio_vec.bv_offset = 0;
 	bio.bi_vcnt = 1;
-	bio.bi_idx = 0;
 	bio.bi_size = size;
 	bio.bi_bdev = bdev;
 	bio.bi_sector = 0;
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 03d6d21..e21dfd5 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -490,7 +490,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 
 	bio->bi_end_io = verity_end_io;
 	bio->bi_private = io;
-	io->io_vec_size = bio->bi_vcnt - bio->bi_idx;
+	io->io_vec_size = bio_segments(bio);
 	if (io->io_vec_size < DM_VERITY_IO_VEC_INLINE)
 		io->io_vec = io->io_vec_inline;
 	else
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 84cd9d7..c2e2abf 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4333,7 +4333,6 @@ read_more:
 	read_bio->bi_flags &= ~(BIO_POOL_MASK - 1);
 	read_bio->bi_flags |= 1 << BIO_UPTODATE;
 	read_bio->bi_vcnt = 0;
-	read_bio->bi_idx = 0;
 	read_bio->bi_size = 0;
 	r10_bio->master_bio = read_bio;
 	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
diff --git a/fs/buffer.c b/fs/buffer.c
index 87ff335..9f509f9 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2978,7 +2978,6 @@ int submit_bh(int rw, struct buffer_head * bh)
 	bio->bi_io_vec[0].bv_offset = bh_offset(bh);
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = bh->b_size;
 
 	bio->bi_end_io = end_bio_bh_io_sync;
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 2eb952c..8ae5e35 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -2004,7 +2004,6 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = LOGPSIZE;
 
 	bio->bi_end_io = lbmIODone;
@@ -2145,7 +2144,6 @@ static void lbmStartIO(struct lbuf * bp)
 	bio->bi_io_vec[0].bv_offset = bp->l_offset;
 
 	bio->bi_vcnt = 1;
-	bio->bi_idx = 0;
 	bio->bi_size = LOGPSIZE;
 
 	bio->bi_end_io = lbmIODone;
diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index e784a21..550475c 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -32,7 +32,6 @@ static int sync_request(struct page *page, struct block_device *bdev, int rw)
 	bio_vec.bv_len = PAGE_SIZE;
 	bio_vec.bv_offset = 0;
 	bio.bi_vcnt = 1;
-	bio.bi_idx = 0;
 	bio.bi_size = PAGE_SIZE;
 	bio.bi_bdev = bdev;
 	bio.bi_sector = page->index * (PAGE_SIZE >> 9);
@@ -108,7 +107,6 @@ static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
 		if (i >= max_pages) {
 			/* Block layer cannot split bios :( */
 			bio->bi_vcnt = i;
-			bio->bi_idx = 0;
 			bio->bi_size = i * PAGE_SIZE;
 			bio->bi_bdev = super->s_bdev;
 			bio->bi_sector = ofs >> 9;
@@ -136,7 +134,6 @@ static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index,
 		unlock_page(page);
 	}
 	bio->bi_vcnt = nr_pages;
-	bio->bi_idx = 0;
 	bio->bi_size = nr_pages * PAGE_SIZE;
 	bio->bi_bdev = super->s_bdev;
 	bio->bi_sector = ofs >> 9;
@@ -202,7 +199,6 @@ static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
 		if (i >= max_pages) {
 			/* Block layer cannot split bios :( */
 			bio->bi_vcnt = i;
-			bio->bi_idx = 0;
 			bio->bi_size = i * PAGE_SIZE;
 			bio->bi_bdev = super->s_bdev;
 			bio->bi_sector = ofs >> 9;
@@ -224,7 +220,6 @@ static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
 		bio->bi_io_vec[i].bv_offset = 0;
 	}
 	bio->bi_vcnt = nr_pages;
-	bio->bi_idx = 0;
 	bio->bi_size = nr_pages * PAGE_SIZE;
 	bio->bi_bdev = super->s_bdev;
 	bio->bi_sector = ofs >> 9;
diff --git a/mm/page_io.c b/mm/page_io.c
index 78eee32..8d3c0c0 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -35,7 +35,6 @@ static struct bio *get_swap_bio(gfp_t gfp_flags,
 		bio->bi_io_vec[0].bv_len = PAGE_SIZE;
 		bio->bi_io_vec[0].bv_offset = 0;
 		bio->bi_vcnt = 1;
-		bio->bi_idx = 0;
 		bio->bi_size = PAGE_SIZE;
 		bio->bi_end_io = end_io;
 	}
-- 
1.7.12

[PATCH 12/27] block: Remove some unnecessary bi_vcnt usage

[Kent Overstreet]

More prep work for immutable bvecs/effecient bio splitting - usage of
bi_vcnt has to be auditing, so getting rid of all the unnecessary usage
makes that easier.

Plus, bio_segments() is really what this code wanted, as it respects the
current value of bi_idx.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Eric Moore <Eric.Moore@lsi.com>
CC: "James E.J. Bottomley" <JBottomley@parallels.com>
CC: linux-scsi@vger.kernel.org
---
 drivers/message/fusion/mptsas.c          |  6 +++---
 drivers/scsi/libsas/sas_expander.c       |  6 +++---
 drivers/scsi/mpt2sas/mpt2sas_transport.c | 10 +++++-----
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/message/fusion/mptsas.c b/drivers/message/fusion/mptsas.c
index fa43c39..2bb0154 100644
--- a/drivers/message/fusion/mptsas.c
+++ b/drivers/message/fusion/mptsas.c
@@ -2235,10 +2235,10 @@ static int mptsas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	}
 
 	/* do we need to support multiple segments? */
-	if (req->bio->bi_vcnt > 1 || rsp->bio->bi_vcnt > 1) {
+	if (bio_segments(req->bio) > 1 || bio_segments(rsp->bio) > 1) {
 		printk(MYIOC_s_ERR_FMT "%s: multiple segments req %u %u, rsp %u %u\n",
-		    ioc->name, __func__, req->bio->bi_vcnt, blk_rq_bytes(req),
-		    rsp->bio->bi_vcnt, blk_rq_bytes(rsp));
+		    ioc->name, __func__, bio_segments(req->bio), blk_rq_bytes(req),
+		    bio_segments(rsp->bio), blk_rq_bytes(rsp));
 		return -EINVAL;
 	}
 
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index aec2e0d..7af7767 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -2151,10 +2151,10 @@ int sas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	}
 
 	/* do we need to support multiple segments? */
-	if (req->bio->bi_vcnt > 1 || rsp->bio->bi_vcnt > 1) {
+	if (bio_segments(req->bio) > 1 || bio_segments(rsp->bio) > 1) {
 		printk("%s: multiple segments req %u %u, rsp %u %u\n",
-		       __func__, req->bio->bi_vcnt, blk_rq_bytes(req),
-		       rsp->bio->bi_vcnt, blk_rq_bytes(rsp));
+		       __func__, bio_segments(req->bio), blk_rq_bytes(req),
+		       bio_segments(rsp->bio), blk_rq_bytes(rsp));
 		return -EINVAL;
 	}
 
diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c
index 8c2ffbe..193e7ae 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_transport.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c
@@ -1939,7 +1939,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	ioc->transport_cmds.status = MPT2_CMD_PENDING;
 
 	/* Check if the request is split across multiple segments */
-	if (req->bio->bi_vcnt > 1) {
+	if (bio_segments(req->bio) > 1) {
 		u32 offset = 0;
 
 		/* Allocate memory and copy the request */
@@ -1971,7 +1971,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 
 	/* Check if the response needs to be populated across
 	 * multiple segments */
-	if (rsp->bio->bi_vcnt > 1) {
+	if (bio_segments(rsp->bio) > 1) {
 		pci_addr_in = pci_alloc_consistent(ioc->pdev, blk_rq_bytes(rsp),
 		    &pci_dma_in);
 		if (!pci_addr_in) {
@@ -2038,7 +2038,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	sgl_flags = (MPI2_SGE_FLAGS_SIMPLE_ELEMENT |
 	    MPI2_SGE_FLAGS_END_OF_BUFFER | MPI2_SGE_FLAGS_HOST_TO_IOC);
 	sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT;
-	if (req->bio->bi_vcnt > 1) {
+	if (bio_segments(req->bio) > 1) {
 		ioc->base_add_sg_single(psge, sgl_flags |
 		    (blk_rq_bytes(req) - 4), pci_dma_out);
 	} else {
@@ -2054,7 +2054,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	    MPI2_SGE_FLAGS_LAST_ELEMENT | MPI2_SGE_FLAGS_END_OF_BUFFER |
 	    MPI2_SGE_FLAGS_END_OF_LIST);
 	sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT;
-	if (rsp->bio->bi_vcnt > 1) {
+	if (bio_segments(rsp->bio) > 1) {
 		ioc->base_add_sg_single(psge, sgl_flags |
 		    (blk_rq_bytes(rsp) + 4), pci_dma_in);
 	} else {
@@ -2099,7 +2099,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 		    le16_to_cpu(mpi_reply->ResponseDataLength);
 		/* check if the resp needs to be copied from the allocated
 		 * pci mem */
-		if (rsp->bio->bi_vcnt > 1) {
+		if (bio_segments(rsp->bio) > 1) {
 			u32 offset = 0;
 			u32 bytes_to_copy =
 			    le16_to_cpu(mpi_reply->ResponseDataLength);
-- 
1.7.12

[PATCH 13/27] block: Add submit_bio_wait(), remove from md

[Kent Overstreet]

Random cleanup - this code was duplicated and it's not really specific
to md.

Also added the ability to return the actual error code.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
---
 drivers/md/raid1.c  | 19 -------------------
 drivers/md/raid10.c | 19 -------------------
 fs/bio.c            | 36 ++++++++++++++++++++++++++++++++++++
 include/linux/bio.h |  1 +
 4 files changed, 37 insertions(+), 38 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index b47503b..3dbdb3d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2056,25 +2056,6 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
 	}
 }
 
-static void bi_complete(struct bio *bio, int error)
-{
-	complete((struct completion *)bio->bi_private);
-}
-
-static int submit_bio_wait(int rw, struct bio *bio)
-{
-	struct completion event;
-	rw |= REQ_SYNC;
-
-	init_completion(&event);
-	bio->bi_private = &event;
-	bio->bi_end_io = bi_complete;
-	submit_bio(rw, bio);
-	wait_for_completion(&event);
-
-	return test_bit(BIO_UPTODATE, &bio->bi_flags);
-}
-
 static int narrow_write_error(struct r1bio *r1_bio, int i)
 {
 	struct mddev *mddev = r1_bio->mddev;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c2e2abf..3cbd3ac 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2479,25 +2479,6 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
 	}
 }
 
-static void bi_complete(struct bio *bio, int error)
-{
-	complete((struct completion *)bio->bi_private);
-}
-
-static int submit_bio_wait(int rw, struct bio *bio)
-{
-	struct completion event;
-	rw |= REQ_SYNC;
-
-	init_completion(&event);
-	bio->bi_private = &event;
-	bio->bi_end_io = bi_complete;
-	submit_bio(rw, bio);
-	wait_for_completion(&event);
-
-	return test_bit(BIO_UPTODATE, &bio->bi_flags);
-}
-
 static int narrow_write_error(struct r10bio *r10_bio, int i)
 {
 	struct bio *bio = r10_bio->master_bio;
diff --git a/fs/bio.c b/fs/bio.c
index f1b4c16..4ce24ee 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -752,6 +752,42 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
 }
 EXPORT_SYMBOL(bio_add_page);
 
+struct submit_bio_ret {
+	struct completion event;
+	int error;
+};
+
+static void submit_bio_wait_endio(struct bio *bio, int error)
+{
+	struct submit_bio_ret *ret = bio->bi_private;
+
+	ret->error = error;
+	complete(&ret->event);
+}
+
+/**
+ * submit_bio_wait - submit a bio, and wait until it completes
+ * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
+ * @bio: The &struct bio which describes the I/O
+ *
+ * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
+ * bio_endio() on failure.
+ */
+int submit_bio_wait(int rw, struct bio *bio)
+{
+	struct submit_bio_ret ret;
+
+	rw |= REQ_SYNC;
+	init_completion(&ret.event);
+	bio->bi_private = &ret;
+	bio->bi_end_io = submit_bio_wait_endio;
+	submit_bio(rw, bio);
+	wait_for_completion(&ret.event);
+
+	return ret.error;
+}
+EXPORT_SYMBOL(submit_bio_wait);
+
 /**
  * bio_advance - increment/complete a bio by some number of bytes
  * @bio:	bio to advance
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 20507eb..b20a9cd 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -249,6 +249,7 @@ extern void bio_endio(struct bio *, int);
 struct request_queue;
 extern int bio_phys_segments(struct request_queue *, struct bio *);
 
+extern int submit_bio_wait(int rw, struct bio *bio);
 extern void bio_advance(struct bio *, unsigned);
 
 extern void bio_init(struct bio *);
-- 
1.7.12

[PATCH 14/27] raid10: Use bio_reset()

[Kent Overstreet]

More prep work for immutable bio vecs, mainly getting rid of references
to bi_idx.

bio_reset was being open coded in a few places. The one in sync_request
was a bit nontrivial to convert, so could use some extra eyeballs.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
Acked-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid10.c | 31 +++++++++----------------------
 1 file changed, 9 insertions(+), 22 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 3cbd3ac..8b5c3f2 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2027,13 +2027,10 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 		 * First we need to fixup bv_offset, bv_len and
 		 * bi_vecs, as the read request might have corrupted these
 		 */
+		bio_reset(tbio);
+
 		tbio->bi_vcnt = vcnt;
 		tbio->bi_size = r10_bio->sectors << 9;
-		tbio->bi_idx = 0;
-		tbio->bi_phys_segments = 0;
-		tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
-		tbio->bi_flags |= 1 << BIO_UPTODATE;
-		tbio->bi_next = NULL;
 		tbio->bi_rw = WRITE;
 		tbio->bi_private = r10_bio;
 		tbio->bi_sector = r10_bio->devs[i].addr;
@@ -3040,6 +3037,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 					}
 				}
 				bio = r10_bio->devs[0].bio;
+				bio_reset(bio);
 				bio->bi_next = biolist;
 				biolist = bio;
 				bio->bi_private = r10_bio;
@@ -3064,6 +3062,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 				rdev = mirror->rdev;
 				if (!test_bit(In_sync, &rdev->flags)) {
 					bio = r10_bio->devs[1].bio;
+					bio_reset(bio);
 					bio->bi_next = biolist;
 					biolist = bio;
 					bio->bi_private = r10_bio;
@@ -3092,6 +3091,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 				if (rdev == NULL || bio == NULL ||
 				    test_bit(Faulty, &rdev->flags))
 					break;
+				bio_reset(bio);
 				bio->bi_next = biolist;
 				biolist = bio;
 				bio->bi_private = r10_bio;
@@ -3190,7 +3190,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 				r10_bio->devs[i].repl_bio->bi_end_io = NULL;
 
 			bio = r10_bio->devs[i].bio;
-			bio->bi_end_io = NULL;
+			bio_reset(bio);
 			clear_bit(BIO_UPTODATE, &bio->bi_flags);
 			if (conf->mirrors[d].rdev == NULL ||
 			    test_bit(Faulty, &conf->mirrors[d].rdev->flags))
@@ -3227,6 +3227,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 
 			/* Need to set up for writing to the replacement */
 			bio = r10_bio->devs[i].repl_bio;
+			bio_reset(bio);
 			clear_bit(BIO_UPTODATE, &bio->bi_flags);
 
 			sector = r10_bio->devs[i].addr;
@@ -3260,17 +3261,6 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 		}
 	}
 
-	for (bio = biolist; bio ; bio=bio->bi_next) {
-
-		bio->bi_flags &= ~(BIO_POOL_MASK - 1);
-		if (bio->bi_end_io)
-			bio->bi_flags |= 1 << BIO_UPTODATE;
-		bio->bi_vcnt = 0;
-		bio->bi_idx = 0;
-		bio->bi_phys_segments = 0;
-		bio->bi_size = 0;
-	}
-
 	nr_sectors = 0;
 	if (sector_nr + max_sync < max_sector)
 		max_sector = sector_nr + max_sync;
@@ -4337,17 +4327,14 @@ read_more:
 		}
 		if (!rdev2 || test_bit(Faulty, &rdev2->flags))
 			continue;
+
+		bio_reset(b);
 		b->bi_bdev = rdev2->bdev;
 		b->bi_sector = r10_bio->devs[s/2].addr + rdev2->new_data_offset;
 		b->bi_private = r10_bio;
 		b->bi_end_io = end_reshape_write;
 		b->bi_rw = WRITE;
-		b->bi_flags &= ~(BIO_POOL_MASK - 1);
-		b->bi_flags |= 1 << BIO_UPTODATE;
 		b->bi_next = blist;
-		b->bi_vcnt = 0;
-		b->bi_idx = 0;
-		b->bi_size = 0;
 		blist = b;
 	}
 
-- 
1.7.12

[PATCH 15/27] raid1: use bio_reset()

[Kent Overstreet]

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 3dbdb3d..e3f98d2 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1859,7 +1859,7 @@ static int process_checks(struct r1bio *r1_bio)
 		struct bio *sbio = r1_bio->bios[i];
 		int size;
 
-		if (r1_bio->bios[i]->bi_end_io != end_sync_read)
+		if (sbio->bi_end_io != end_sync_read)
 			continue;
 
 		if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
@@ -1884,16 +1884,15 @@ static int process_checks(struct r1bio *r1_bio)
 			continue;
 		}
 		/* fixup the bio for reuse */
+		bio_reset(sbio);
 		sbio->bi_vcnt = vcnt;
 		sbio->bi_size = r1_bio->sectors << 9;
-		sbio->bi_idx = 0;
-		sbio->bi_phys_segments = 0;
-		sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
-		sbio->bi_flags |= 1 << BIO_UPTODATE;
-		sbio->bi_next = NULL;
 		sbio->bi_sector = r1_bio->sector +
 			conf->mirrors[i].rdev->data_offset;
 		sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+		sbio->bi_end_io = end_sync_read;
+		sbio->bi_private = r1_bio;
+
 		size = sbio->bi_size;
 		for (j = 0; j < vcnt ; j++) {
 			struct bio_vec *bi;
@@ -2436,18 +2435,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
 	for (i = 0; i < conf->raid_disks * 2; i++) {
 		struct md_rdev *rdev;
 		bio = r1_bio->bios[i];
-
-		/* take from bio_init */
-		bio->bi_next = NULL;
-		bio->bi_flags &= ~(BIO_POOL_MASK-1);
-		bio->bi_flags |= 1 << BIO_UPTODATE;
-		bio->bi_rw = READ;
-		bio->bi_vcnt = 0;
-		bio->bi_idx = 0;
-		bio->bi_phys_segments = 0;
-		bio->bi_size = 0;
-		bio->bi_end_io = NULL;
-		bio->bi_private = NULL;
+		bio_reset(bio);
 
 		rdev = rcu_dereference(conf->mirrors[i].rdev);
 		if (rdev == NULL ||
-- 
1.7.12

[PATCH 16/27] raid5: use bio_reset()

[Kent Overstreet]

Had to shuffle the code around a bit (where bi_rw and bi_end_io were
set), but shouldn't really be anything tricky here

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0ba12c3..b1b2188 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -568,14 +568,6 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 		bi = &sh->dev[i].req;
 		rbi = &sh->dev[i].rreq; /* For writing to replacement */
 
-		bi->bi_rw = rw;
-		rbi->bi_rw = rw;
-		if (rw & WRITE) {
-			bi->bi_end_io = raid5_end_write_request;
-			rbi->bi_end_io = raid5_end_write_request;
-		} else
-			bi->bi_end_io = raid5_end_read_request;
-
 		rcu_read_lock();
 		rrdev = rcu_dereference(conf->disks[i].replacement);
 		smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
@@ -650,7 +642,14 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 
 			set_bit(STRIPE_IO_STARTED, &sh->state);
 
+			bio_reset(bi);
 			bi->bi_bdev = rdev->bdev;
+			bi->bi_rw = rw;
+			bi->bi_end_io = (rw & WRITE)
+				? raid5_end_write_request
+				: raid5_end_read_request;
+			bi->bi_private = sh;
+
 			pr_debug("%s: for %llu schedule op %ld on disc %d\n",
 				__func__, (unsigned long long)sh->sector,
 				bi->bi_rw, i);
@@ -664,12 +663,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 			if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
 				bi->bi_rw |= REQ_FLUSH;
 
-			bi->bi_flags = 1 << BIO_UPTODATE;
-			bi->bi_idx = 0;
 			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
 			bi->bi_io_vec[0].bv_offset = 0;
 			bi->bi_size = STRIPE_SIZE;
-			bi->bi_next = NULL;
 			if (rrdev)
 				set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
 			trace_block_bio_remap(bdev_get_queue(bi->bi_bdev),
@@ -684,7 +680,13 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 
 			set_bit(STRIPE_IO_STARTED, &sh->state);
 
+			bio_reset(rbi);
 			rbi->bi_bdev = rrdev->bdev;
+			rbi->bi_rw = rw;
+			BUG_ON(!(rw & WRITE));
+			rbi->bi_end_io = raid5_end_write_request;
+			rbi->bi_private = sh;
+
 			pr_debug("%s: for %llu schedule op %ld on "
 				 "replacement disc %d\n",
 				__func__, (unsigned long long)sh->sector,
@@ -696,12 +698,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 			else
 				rbi->bi_sector = (sh->sector
 						  + rrdev->data_offset);
-			rbi->bi_flags = 1 << BIO_UPTODATE;
-			rbi->bi_idx = 0;
 			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
 			rbi->bi_io_vec[0].bv_offset = 0;
 			rbi->bi_size = STRIPE_SIZE;
-			rbi->bi_next = NULL;
 			trace_block_bio_remap(bdev_get_queue(rbi->bi_bdev),
 					      rbi, disk_devt(conf->mddev->gendisk),
 					      sh->dev[i].sector);
-- 
1.7.12

[PATCH 17/27] raid1: Refactor narrow_write_error() to not use bi_idx

[Kent Overstreet]

More bi_idx removal. This code was just open coding bio_clone(). This
could probably be further improved by using bio_advance() instead of
skipping over null pages, but that'd be a larger rework.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e3f98d2..8839b8d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2060,8 +2060,6 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
 	struct mddev *mddev = r1_bio->mddev;
 	struct r1conf *conf = mddev->private;
 	struct md_rdev *rdev = conf->mirrors[i].rdev;
-	int vcnt, idx;
-	struct bio_vec *vec;
 
 	/* bio has the data to be written to device 'i' where
 	 * we just recently had a write error.
@@ -2089,30 +2087,32 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
 		   & ~(sector_t)(block_sectors - 1))
 		- sector;
 
-	if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
-		vcnt = r1_bio->behind_page_count;
-		vec = r1_bio->behind_bvecs;
-		idx = 0;
-		while (vec[idx].bv_page == NULL)
-			idx++;
-	} else {
-		vcnt = r1_bio->master_bio->bi_vcnt;
-		vec = r1_bio->master_bio->bi_io_vec;
-		idx = r1_bio->master_bio->bi_idx;
-	}
 	while (sect_to_write) {
 		struct bio *wbio;
 		if (sectors > sect_to_write)
 			sectors = sect_to_write;
 		/* Write at 'sector' for 'sectors'*/
 
-		wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
-		memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
-		wbio->bi_sector = r1_bio->sector;
+		if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
+			unsigned vcnt = r1_bio->behind_page_count;
+			struct bio_vec *vec = r1_bio->behind_bvecs;
+
+			while (!vec->bv_page) {
+				vec++;
+				vcnt--;
+			}
+
+			wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
+			memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
+
+			wbio->bi_vcnt = vcnt;
+		} else {
+			wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+		}
+
 		wbio->bi_rw = WRITE;
-		wbio->bi_vcnt = vcnt;
+		wbio->bi_sector = r1_bio->sector;
 		wbio->bi_size = r1_bio->sectors << 9;
-		wbio->bi_idx = idx;
 
 		md_trim_bio(wbio, sector - r1_bio->sector, sectors);
 		wbio->bi_sector += rdev->data_offset;
-- 
1.7.12

[PATCH 18/27] block: Add bio_copy_data()

[Kent Overstreet]

This gets open coded quite a bit and it's tricky to get right, so make a
generic version and convert some existing users over to it instead.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 fs/bio.c            | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/bio.h |  2 ++
 2 files changed, 72 insertions(+)

diff --git a/fs/bio.c b/fs/bio.c
index 4ce24ee..e437f9aa 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -829,6 +829,76 @@ void bio_advance(struct bio *bio, unsigned bytes)
 }
 EXPORT_SYMBOL(bio_advance);
 
+/**
+ * bio_copy_data - copy contents of data buffers from one chain of bios to
+ * another
+ * @src: source bio list
+ * @dst: destination bio list
+ *
+ * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
+ * @src and @dst as linked lists of bios.
+ *
+ * Stops when it reaches the end of either @src or @dst - that is, copies
+ * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
+ */
+void bio_copy_data(struct bio *dst, struct bio *src)
+{
+	struct bio_vec *src_bv, *dst_bv;
+	unsigned src_offset, dst_offset, bytes;
+	void *src_p, *dst_p;
+
+	src_bv = bio_iovec(src);
+	dst_bv = bio_iovec(dst);
+
+	src_offset = src_bv->bv_offset;
+	dst_offset = dst_bv->bv_offset;
+
+	while (1) {
+		if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
+			src_bv++;
+			if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
+				src = src->bi_next;
+				if (!src)
+					break;
+
+				src_bv = bio_iovec(src);
+			}
+
+			src_offset = src_bv->bv_offset;
+		}
+
+		if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
+			dst_bv++;
+			if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
+				dst = dst->bi_next;
+				if (!dst)
+					break;
+
+				dst_bv = bio_iovec(dst);
+			}
+
+			dst_offset = dst_bv->bv_offset;
+		}
+
+		bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
+			    src_bv->bv_offset + src_bv->bv_len - src_offset);
+
+		src_p = kmap_atomic(src_bv->bv_page);
+		dst_p = kmap_atomic(dst_bv->bv_page);
+
+		memcpy(dst_p + dst_bv->bv_offset,
+		       src_p + src_bv->bv_offset,
+		       bytes);
+
+		kunmap_atomic(dst_p);
+		kunmap_atomic(src_p);
+
+		src_offset += bytes;
+		dst_offset += bytes;
+	}
+}
+EXPORT_SYMBOL(bio_copy_data);
+
 struct bio_map_data {
 	struct bio_vec *iovecs;
 	struct sg_iovec *sgvecs;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b20a9cd..90d36c6 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -286,6 +286,8 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
 }
 #endif
 
+extern void bio_copy_data(struct bio *dst, struct bio *src);
+
 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 				 unsigned long, unsigned int, int, gfp_t);
 extern struct bio *bio_copy_user_iov(struct request_queue *,
-- 
1.7.12

[PATCH 19/27] pktcdvd: use bio_copy_data()

[Kent Overstreet]

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Jiri Kosina <jkosina@suse.cz>
---
 drivers/block/pktcdvd.c | 79 ++++++++-----------------------------------------
 1 file changed, 12 insertions(+), 67 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 2c27744..783c96c 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -948,31 +948,6 @@ static int pkt_set_segment_merging(struct pktcdvd_device *pd, struct request_que
 }
 
 /*
- * Copy CD_FRAMESIZE bytes from src_bio into a destination page
- */
-static void pkt_copy_bio_data(struct bio *src_bio, int seg, int offs, struct page *dst_page, int dst_offs)
-{
-	unsigned int copy_size = CD_FRAMESIZE;
-
-	while (copy_size > 0) {
-		struct bio_vec *src_bvl = bio_iovec_idx(src_bio, seg);
-		void *vfrom = kmap_atomic(src_bvl->bv_page) +
-			src_bvl->bv_offset + offs;
-		void *vto = page_address(dst_page) + dst_offs;
-		int len = min_t(int, copy_size, src_bvl->bv_len - offs);
-
-		BUG_ON(len < 0);
-		memcpy(vto, vfrom, len);
-		kunmap_atomic(vfrom);
-
-		seg++;
-		offs = 0;
-		dst_offs += len;
-		copy_size -= len;
-	}
-}
-
-/*
  * Copy all data for this packet to pkt->pages[], so that
  * a) The number of required segments for the write bio is minimized, which
  *    is necessary for some scsi controllers.
@@ -1325,55 +1300,35 @@ try_next_bio:
  */
 static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
 {
-	struct bio *bio;
 	int f;
-	int frames_write;
 	struct bio_vec *bvec = pkt->w_bio->bi_io_vec;
 
+	bio_reset(pkt->w_bio);
+	pkt->w_bio->bi_sector = pkt->sector;
+	pkt->w_bio->bi_bdev = pd->bdev;
+	pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
+	pkt->w_bio->bi_private = pkt;
+
+	/* XXX: locking? */
 	for (f = 0; f < pkt->frames; f++) {
 		bvec[f].bv_page = pkt->pages[(f * CD_FRAMESIZE) / PAGE_SIZE];
 		bvec[f].bv_offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
+		if (!bio_add_page(pkt->w_bio, bvec[f].bv_page, CD_FRAMESIZE, bvec[f].bv_offset))
+			BUG();
 	}
+	VPRINTK(DRIVER_NAME": vcnt=%d\n", pkt->w_bio->bi_vcnt);
 
 	/*
 	 * Fill-in bvec with data from orig_bios.
 	 */
-	frames_write = 0;
 	spin_lock(&pkt->lock);
-	bio_list_for_each(bio, &pkt->orig_bios) {
-		int segment = bio->bi_idx;
-		int src_offs = 0;
-		int first_frame = (bio->bi_sector - pkt->sector) / (CD_FRAMESIZE >> 9);
-		int num_frames = bio->bi_size / CD_FRAMESIZE;
-		BUG_ON(first_frame < 0);
-		BUG_ON(first_frame + num_frames > pkt->frames);
-		for (f = first_frame; f < first_frame + num_frames; f++) {
-			struct bio_vec *src_bvl = bio_iovec_idx(bio, segment);
-
-			while (src_offs >= src_bvl->bv_len) {
-				src_offs -= src_bvl->bv_len;
-				segment++;
-				BUG_ON(segment >= bio->bi_vcnt);
-				src_bvl = bio_iovec_idx(bio, segment);
-			}
+	bio_copy_data(pkt->w_bio, pkt->orig_bios.head);
 
-			if (src_bvl->bv_len - src_offs >= CD_FRAMESIZE) {
-				bvec[f].bv_page = src_bvl->bv_page;
-				bvec[f].bv_offset = src_bvl->bv_offset + src_offs;
-			} else {
-				pkt_copy_bio_data(bio, segment, src_offs,
-						  bvec[f].bv_page, bvec[f].bv_offset);
-			}
-			src_offs += CD_FRAMESIZE;
-			frames_write++;
-		}
-	}
 	pkt_set_state(pkt, PACKET_WRITE_WAIT_STATE);
 	spin_unlock(&pkt->lock);
 
 	VPRINTK("pkt_start_write: Writing %d frames for zone %llx\n",
-		frames_write, (unsigned long long)pkt->sector);
-	BUG_ON(frames_write != pkt->write_size);
+		pkt->write_size, (unsigned long long)pkt->sector);
 
 	if (test_bit(PACKET_MERGE_SEGS, &pd->flags) || (pkt->write_size < pkt->frames)) {
 		pkt_make_local_copy(pkt, bvec);
@@ -1383,16 +1338,6 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
 	}
 
 	/* Start the write request */
-	bio_reset(pkt->w_bio);
-	pkt->w_bio->bi_sector = pkt->sector;
-	pkt->w_bio->bi_bdev = pd->bdev;
-	pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
-	pkt->w_bio->bi_private = pkt;
-	for (f = 0; f < pkt->frames; f++)
-		if (!bio_add_page(pkt->w_bio, bvec[f].bv_page, CD_FRAMESIZE, bvec[f].bv_offset))
-			BUG();
-	VPRINTK(DRIVER_NAME": vcnt=%d\n", pkt->w_bio->bi_vcnt);
-
 	atomic_set(&pkt->io_wait, 1);
 	pkt->w_bio->bi_rw = WRITE;
 	pkt_queue_bio(pd, pkt->w_bio);
-- 
1.7.12

[PATCH 20/27] pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage

[Kent Overstreet]

In the short term this'll help with code auditing, and if this code ever
gets used now it's converted :)

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jiri Kosina <jkosina@suse.cz>
---
 drivers/block/pktcdvd.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 783c96c..1119042 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1156,16 +1156,15 @@ static int pkt_start_recovery(struct packet_data *pkt)
 	new_sector = new_block * (CD_FRAMESIZE >> 9);
 	pkt->sector = new_sector;
 
+	bio_reset(pkt->bio);
+	pkt->bio->bi_bdev = pd->bdev;
+	pkt->bio->bi_rw = REQ_WRITE;
 	pkt->bio->bi_sector = new_sector;
-	pkt->bio->bi_next = NULL;
-	pkt->bio->bi_flags = 1 << BIO_UPTODATE;
-	pkt->bio->bi_idx = 0;
-
-	BUG_ON(pkt->bio->bi_rw != REQ_WRITE);
-	BUG_ON(pkt->bio->bi_vcnt != pkt->frames);
-	BUG_ON(pkt->bio->bi_size != pkt->frames * CD_FRAMESIZE);
-	BUG_ON(pkt->bio->bi_end_io != pkt_end_io_packet_write);
-	BUG_ON(pkt->bio->bi_private != pkt);
+	pkt->bio->bi_size = pkt->frames * CD_FRAMESIZE;
+	pkt->bio->bi_vcnt = pkt->frames;
+
+	pkt->bio->bi_end_io = pkt_end_io_packet_write;
+	pkt->bio->bi_private = pkt;
 
 	drop_super(sb);
 	return 1;
-- 
1.7.12

[PATCH 21/27] raid1: use bio_copy_data()

[Kent Overstreet]

This doesn't really delete any code _yet_, but once immutable bvecs are
done we can just delete the rest of the code in that loop.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 8839b8d..1fd0888 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1903,10 +1903,9 @@ static int process_checks(struct r1bio *r1_bio)
 			else
 				bi->bv_len = size;
 			size -= PAGE_SIZE;
-			memcpy(page_address(bi->bv_page),
-			       page_address(pbio->bi_io_vec[j].bv_page),
-			       PAGE_SIZE);
 		}
+
+		bio_copy_data(sbio, pbio);
 	}
 	return 0;
 }
-- 
1.7.12

[PATCH 22/27] bounce: Refactor __blk_queue_bounce to not use bi_io_vec

[Kent Overstreet]

A bunch of what __blk_queue_bounce() was doing was problematic for the
immutable bvec work; this cleans that up and the code is quite a bit
smaller, too.

The __bio_for_each_segment() in copy_to_high_bio_irq() was changed
because that one's looping over the original bio, not the bounce bio -
a later patch renames __bio_for_each_segment() ->
bio_for_each_segment_all(), and documents that
bio_for_each_segment_all() is only for code that owns the bio.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
---
 mm/bounce.c | 73 ++++++++++++++++---------------------------------------------
 1 file changed, 19 insertions(+), 54 deletions(-)

diff --git a/mm/bounce.c b/mm/bounce.c
index 0420867..3068300 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -101,7 +101,7 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
 	struct bio_vec *tovec, *fromvec;
 	int i;
 
-	__bio_for_each_segment(tovec, to, i, 0) {
+	bio_for_each_segment(tovec, to, i) {
 		fromvec = from->bi_io_vec + i;
 
 		/*
@@ -181,78 +181,43 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
 static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
 			       mempool_t *pool)
 {
-	struct page *page;
-	struct bio *bio = NULL;
-	int i, rw = bio_data_dir(*bio_orig);
+	struct bio *bio;
+	int rw = bio_data_dir(*bio_orig);
 	struct bio_vec *to, *from;
+	unsigned i;
 
-	bio_for_each_segment(from, *bio_orig, i) {
-		page = from->bv_page;
+	bio_for_each_segment(from, *bio_orig, i)
+		if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q))
+			goto bounce;
 
-		/*
-		 * is destination page below bounce pfn?
-		 */
-		if (page_to_pfn(page) <= queue_bounce_pfn(q))
-			continue;
-
-		/*
-		 * irk, bounce it
-		 */
-		if (!bio) {
-			unsigned int cnt = (*bio_orig)->bi_vcnt;
+	return;
+bounce:
+	bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
 
-			bio = bio_alloc(GFP_NOIO, cnt);
-			memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
-		}
-			
+	bio_for_each_segment(to, bio, i) {
+		struct page *page = to->bv_page;
 
-		to = bio->bi_io_vec + i;
+		if (page_to_pfn(page) <= queue_bounce_pfn(q))
+			continue;
 
-		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
-		to->bv_len = from->bv_len;
-		to->bv_offset = from->bv_offset;
 		inc_zone_page_state(to->bv_page, NR_BOUNCE);
+		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
 
 		if (rw == WRITE) {
 			char *vto, *vfrom;
 
-			flush_dcache_page(from->bv_page);
+			flush_dcache_page(page);
+
 			vto = page_address(to->bv_page) + to->bv_offset;
-			vfrom = kmap(from->bv_page) + from->bv_offset;
+			vfrom = kmap_atomic(page) + to->bv_offset;
 			memcpy(vto, vfrom, to->bv_len);
-			kunmap(from->bv_page);
+			kunmap_atomic(vfrom);
 		}
 	}
 
-	/*
-	 * no pages bounced
-	 */
-	if (!bio)
-		return;
-
 	trace_block_bio_bounce(q, *bio_orig);
 
-	/*
-	 * at least one page was bounced, fill in possible non-highmem
-	 * pages
-	 */
-	__bio_for_each_segment(from, *bio_orig, i, 0) {
-		to = bio_iovec_idx(bio, i);
-		if (!to->bv_page) {
-			to->bv_page = from->bv_page;
-			to->bv_len = from->bv_len;
-			to->bv_offset = from->bv_offset;
-		}
-	}
-
-	bio->bi_bdev = (*bio_orig)->bi_bdev;
 	bio->bi_flags |= (1 << BIO_BOUNCED);
-	bio->bi_sector = (*bio_orig)->bi_sector;
-	bio->bi_rw = (*bio_orig)->bi_rw;
-
-	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
-	bio->bi_idx = (*bio_orig)->bi_idx;
-	bio->bi_size = (*bio_orig)->bi_size;
 
 	if (pool == page_pool) {
 		bio->bi_end_io = bounce_end_io_write;
-- 
1.7.12

[PATCH 23/27] block: Add bio_for_each_segment_all()

[Kent Overstreet]

__bio_for_each_segment() iterates bvecs from the specified index
instead of bio->bv_idx.  Currently, the only usage is to walk all the
bvecs after the bio has been advanced by specifying 0 index.

For immutable bvecs, we need to split these apart;
bio_for_each_segment() is going to have a different implementation.
This will also help document the intent of code that's using it -
bio_for_each_segment_all() is only legal to use for code that owns the
bio.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Neil Brown <neilb@suse.de>
CC: Boaz Harrosh <bharrosh@panasas.com>
---
 drivers/block/rbd.c |  2 +-
 drivers/md/raid1.c  |  2 +-
 fs/bio.c            | 12 ++++++------
 fs/exofs/ore.c      |  2 +-
 fs/exofs/ore_raid.c |  2 +-
 include/linux/bio.h | 17 ++++++++++++++---
 mm/bounce.c         |  2 +-
 7 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 89576a0..f1daada 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -866,7 +866,7 @@ static struct bio *bio_clone_range(struct bio *bio_src,
 	/* Find first affected segment... */
 
 	resid = offset;
-	__bio_for_each_segment(bv, bio_src, idx, 0) {
+	bio_for_each_segment(bv, bio_src, idx) {
 		if (resid < bv->bv_len)
 			break;
 		resid -= bv->bv_len;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 1fd0888..3716fe4 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1289,7 +1289,7 @@ read_again:
 			 * know the original bi_idx, so we just free
 			 * them all
 			 */
-			__bio_for_each_segment(bvec, mbio, j, 0)
+			bio_for_each_segment_all(bvec, mbio, j)
 				bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
 			if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
 				atomic_inc(&r1_bio->behind_remaining);
diff --git a/fs/bio.c b/fs/bio.c
index e437f9aa..618f904 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -961,7 +961,7 @@ static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
 	int iov_idx = 0;
 	unsigned int iov_off = 0;
 
-	__bio_for_each_segment(bvec, bio, i, 0) {
+	bio_for_each_segment_all(bvec, bio, i) {
 		char *bv_addr = page_address(bvec->bv_page);
 		unsigned int bv_len = iovecs[i].bv_len;
 
@@ -1143,7 +1143,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 	return bio;
 cleanup:
 	if (!map_data)
-		bio_for_each_segment(bvec, bio, i)
+		bio_for_each_segment_all(bvec, bio, i)
 			__free_page(bvec->bv_page);
 
 	bio_put(bio);
@@ -1357,7 +1357,7 @@ static void __bio_unmap_user(struct bio *bio)
 	/*
 	 * make sure we dirty pages we wrote to
 	 */
-	__bio_for_each_segment(bvec, bio, i, 0) {
+	bio_for_each_segment_all(bvec, bio, i) {
 		if (bio_data_dir(bio) == READ)
 			set_page_dirty_lock(bvec->bv_page);
 
@@ -1463,7 +1463,7 @@ static void bio_copy_kern_endio(struct bio *bio, int err)
 	int i;
 	char *p = bmd->sgvecs[0].iov_base;
 
-	__bio_for_each_segment(bvec, bio, i, 0) {
+	bio_for_each_segment_all(bvec, bio, i) {
 		char *addr = page_address(bvec->bv_page);
 		int len = bmd->iovecs[i].bv_len;
 
@@ -1503,7 +1503,7 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
 	if (!reading) {
 		void *p = data;
 
-		bio_for_each_segment(bvec, bio, i) {
+		bio_for_each_segment_all(bvec, bio, i) {
 			char *addr = page_address(bvec->bv_page);
 
 			memcpy(addr, p, bvec->bv_len);
@@ -1789,7 +1789,7 @@ sector_t bio_sector_offset(struct bio *bio, unsigned short index,
 	if (index >= bio->bi_idx)
 		index = bio->bi_vcnt - 1;
 
-	__bio_for_each_segment(bv, bio, i, 0) {
+	bio_for_each_segment_all(bv, bio, i) {
 		if (i == index) {
 			if (offset > bv->bv_offset)
 				sectors += (offset - bv->bv_offset) / sector_sz;
diff --git a/fs/exofs/ore.c b/fs/exofs/ore.c
index f936cb5..b744228 100644
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -401,7 +401,7 @@ static void _clear_bio(struct bio *bio)
 	struct bio_vec *bv;
 	unsigned i;
 
-	__bio_for_each_segment(bv, bio, i, 0) {
+	bio_for_each_segment_all(bv, bio, i) {
 		unsigned this_count = bv->bv_len;
 
 		if (likely(PAGE_SIZE == this_count))
diff --git a/fs/exofs/ore_raid.c b/fs/exofs/ore_raid.c
index b963f38..7682b97 100644
--- a/fs/exofs/ore_raid.c
+++ b/fs/exofs/ore_raid.c
@@ -432,7 +432,7 @@ static void _mark_read4write_pages_uptodate(struct ore_io_state *ios, int ret)
 		if (!bio)
 			continue;
 
-		__bio_for_each_segment(bv, bio, i, 0) {
+		bio_for_each_segment_all(bv, bio, i) {
 			struct page *page = bv->bv_page;
 
 			SetPageUptodate(page);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 90d36c6..be2efa0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -137,16 +137,27 @@ static inline int bio_has_allocated_vec(struct bio *bio)
 #define bio_io_error(bio) bio_endio((bio), -EIO)
 
 /*
- * drivers should not use the __ version unless they _really_ want to
- * run through the entire bio and not just pending pieces
+ * drivers should not use the __ version unless they _really_ know what
+ * they're doing
  */
 #define __bio_for_each_segment(bvl, bio, i, start_idx)			\
 	for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);	\
 	     i < (bio)->bi_vcnt;					\
 	     bvl++, i++)
 
+/*
+ * drivers should _never_ use the all version - the bio may have been split
+ * before it got to the driver and the driver won't own all of it
+ */
+#define bio_for_each_segment_all(bvl, bio, i)				\
+	for (i = 0;							\
+	     bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt;	\
+	     i++)
+
 #define bio_for_each_segment(bvl, bio, i)				\
-	__bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
+	for (i = (bio)->bi_idx;						\
+	     bvl = bio_iovec_idx((bio), (i)), i < (bio)->bi_vcnt;	\
+	     i++)
 
 /*
  * get a reference to a bio, so it won't disappear. the intended use is
diff --git a/mm/bounce.c b/mm/bounce.c
index 3068300..89324e2 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -134,7 +134,7 @@ static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
 	/*
 	 * free up bounce indirect pages used
 	 */
-	__bio_for_each_segment(bvec, bio, i, 0) {
+	bio_for_each_segment_all(bvec, bio, i) {
 		org_vec = bio_orig->bi_io_vec + i;
 		if (bvec->bv_page == org_vec->bv_page)
 			continue;
-- 
1.7.12

[PATCH 24/27] block: Convert some code to bio_for_each_segment_all()

[Kent Overstreet]

More prep work for immutable bvecs:

A few places in the code were either open coding or using the wrong
version - fix.

After we introduce the bvec iter, it'll no longer be possible to modify
the biovec through bio_for_each_segment_all() - it doesn't increment a
pointer to the current bvec, you pass in a struct bio_vec (not a
pointer) which is updated with what the current biovec would be (taking
into account bi_bvec_done and bi_size).

So because of that it's more worthwhile to be consistent about
bio_for_each_segment()/bio_for_each_segment_all() usage.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Alexander Viro <viro@zeniv.linux.org.uk>
---
 drivers/md/dm-crypt.c |  3 +--
 drivers/md/raid1.c    | 10 +++-------
 fs/bio.c              | 20 ++++++++++----------
 fs/direct-io.c        |  8 ++++----
 mm/bounce.c           |  2 +-
 5 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f7369f9..a7923bf 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -858,8 +858,7 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 	unsigned int i;
 	struct bio_vec *bv;
 
-	for (i = 0; i < clone->bi_vcnt; i++) {
-		bv = bio_iovec_idx(clone, i);
+	bio_for_each_segment_all(bv, clone, i) {
 		BUG_ON(!bv->bv_page);
 		mempool_free(bv->bv_page, cc->page_pool);
 		bv->bv_page = NULL;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 3716fe4..981fd4f 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -925,7 +925,7 @@ static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio)
 	if (unlikely(!bvecs))
 		return;
 
-	bio_for_each_segment(bvec, bio, i) {
+	bio_for_each_segment_all(bvec, bio, i) {
 		bvecs[i] = *bvec;
 		bvecs[i].bv_page = alloc_page(GFP_NOIO);
 		if (unlikely(!bvecs[i].bv_page))
@@ -1282,12 +1282,8 @@ read_again:
 			struct bio_vec *bvec;
 			int j;
 
-			/* Yes, I really want the '__' version so that
-			 * we clear any unused pointer in the io_vec, rather
-			 * than leave them unchanged.  This is important
-			 * because when we come to free the pages, we won't
-			 * know the original bi_idx, so we just free
-			 * them all
+			/*
+			 * We trimmed the bio, so _all is legit
 			 */
 			bio_for_each_segment_all(bvec, mbio, j)
 				bvec->bv_page = r1_bio->behind_bvecs[j].bv_page;
diff --git a/fs/bio.c b/fs/bio.c
index 618f904..fe3aee90 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1548,11 +1548,11 @@ EXPORT_SYMBOL(bio_copy_kern);
  */
 void bio_set_pages_dirty(struct bio *bio)
 {
-	struct bio_vec *bvec = bio->bi_io_vec;
+	struct bio_vec *bvec;
 	int i;
 
-	for (i = 0; i < bio->bi_vcnt; i++) {
-		struct page *page = bvec[i].bv_page;
+	bio_for_each_segment_all(bvec, bio, i) {
+		struct page *page = bvec->bv_page;
 
 		if (page && !PageCompound(page))
 			set_page_dirty_lock(page);
@@ -1561,11 +1561,11 @@ void bio_set_pages_dirty(struct bio *bio)
 
 static void bio_release_pages(struct bio *bio)
 {
-	struct bio_vec *bvec = bio->bi_io_vec;
+	struct bio_vec *bvec;
 	int i;
 
-	for (i = 0; i < bio->bi_vcnt; i++) {
-		struct page *page = bvec[i].bv_page;
+	bio_for_each_segment_all(bvec, bio, i) {
+		struct page *page = bvec->bv_page;
 
 		if (page)
 			put_page(page);
@@ -1614,16 +1614,16 @@ static void bio_dirty_fn(struct work_struct *work)
 
 void bio_check_pages_dirty(struct bio *bio)
 {
-	struct bio_vec *bvec = bio->bi_io_vec;
+	struct bio_vec *bvec;
 	int nr_clean_pages = 0;
 	int i;
 
-	for (i = 0; i < bio->bi_vcnt; i++) {
-		struct page *page = bvec[i].bv_page;
+	bio_for_each_segment_all(bvec, bio, i) {
+		struct page *page = bvec->bv_page;
 
 		if (PageDirty(page) || PageCompound(page)) {
 			page_cache_release(page);
-			bvec[i].bv_page = NULL;
+			bvec->bv_page = NULL;
 		} else {
 			nr_clean_pages++;
 		}
diff --git a/fs/direct-io.c b/fs/direct-io.c
index cf5b44b..b51510b 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -441,8 +441,8 @@ static struct bio *dio_await_one(struct dio *dio)
 static int dio_bio_complete(struct dio *dio, struct bio *bio)
 {
 	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-	struct bio_vec *bvec = bio->bi_io_vec;
-	int page_no;
+	struct bio_vec *bvec;
+	unsigned i;
 
 	if (!uptodate)
 		dio->io_error = -EIO;
@@ -450,8 +450,8 @@ static int dio_bio_complete(struct dio *dio, struct bio *bio)
 	if (dio->is_async && dio->rw == READ) {
 		bio_check_pages_dirty(bio);	/* transfers ownership */
 	} else {
-		for (page_no = 0; page_no < bio->bi_vcnt; page_no++) {
-			struct page *page = bvec[page_no].bv_page;
+		bio_for_each_segment_all(bvec, bio, i) {
+			struct page *page = bvec->bv_page;
 
 			if (dio->rw == READ && !PageCompound(page))
 				set_page_dirty_lock(page);
diff --git a/mm/bounce.c b/mm/bounce.c
index 89324e2..bd7079a 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -194,7 +194,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
 bounce:
 	bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
 
-	bio_for_each_segment(to, bio, i) {
+	bio_for_each_segment_all(to, bio, i) {
 		struct page *page = to->bv_page;
 
 		if (page_to_pfn(page) <= queue_bounce_pfn(q))
-- 
1.7.12

[PATCH 25/27] block: Add bio_alloc_pages()

[Kent Overstreet]

More utility code to replace stuff that's getting open coded.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c  | 16 +++-------------
 fs/bio.c            | 28 ++++++++++++++++++++++++++++
 include/linux/bio.h |  1 +
 3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 981fd4f..95afd45 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -92,7 +92,6 @@ static void r1bio_pool_free(void *r1_bio, void *data)
 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 {
 	struct pool_info *pi = data;
-	struct page *page;
 	struct r1bio *r1_bio;
 	struct bio *bio;
 	int i, j;
@@ -122,14 +121,10 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 		j = 1;
 	while(j--) {
 		bio = r1_bio->bios[j];
-		for (i = 0; i < RESYNC_PAGES; i++) {
-			page = alloc_page(gfp_flags);
-			if (unlikely(!page))
-				goto out_free_pages;
+		bio->bi_vcnt = RESYNC_PAGES;
 
-			bio->bi_io_vec[i].bv_page = page;
-			bio->bi_vcnt = i+1;
-		}
+		if (bio_alloc_pages(bio, gfp_flags))
+			goto out_free_bio;
 	}
 	/* If not user-requests, copy the page pointers to all bios */
 	if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
@@ -143,11 +138,6 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
 
 	return r1_bio;
 
-out_free_pages:
-	for (j=0 ; j < pi->raid_disks; j++)
-		for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
-			put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
-	j = -1;
 out_free_bio:
 	while (++j < pi->raid_disks)
 		bio_put(r1_bio->bios[j]);
diff --git a/fs/bio.c b/fs/bio.c
index fe3aee90..e545a44 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -830,6 +830,34 @@ void bio_advance(struct bio *bio, unsigned bytes)
 EXPORT_SYMBOL(bio_advance);
 
 /**
+ * bio_alloc_pages - allocates a single page for each bvec in a bio
+ * @bio: bio to allocate pages for
+ * @gfp_mask: flags for allocation
+ *
+ * Allocates pages up to @bio->bi_vcnt.
+ *
+ * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
+ * freed.
+ */
+int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
+{
+	int i;
+	struct bio_vec *bv;
+
+	bio_for_each_segment_all(bv, bio, i) {
+		bv->bv_page = alloc_page(gfp_mask);
+		if (!bv->bv_page) {
+			while (--bv >= bio->bi_io_vec)
+				__free_page(bv->bv_page);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(bio_alloc_pages);
+
+/**
  * bio_copy_data - copy contents of data buffers from one chain of bios to
  * another
  * @src: source bio list
diff --git a/include/linux/bio.h b/include/linux/bio.h
index be2efa0..e25378f 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -298,6 +298,7 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
 #endif
 
 extern void bio_copy_data(struct bio *dst, struct bio *src);
+extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 
 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 				 unsigned long, unsigned int, int, gfp_t);
-- 
1.7.12

[PATCH 26/27] block: Add an explicit bio flag for bios that own their bvec

[Kent Overstreet]

This is for the new bio splitting code. When we split a bio, if the
split occured on a bvec boundry we reuse the bvec for the new bio. But
that means bio_free() can't free it, hence the explicit flag.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/bio.c                  | 4 +++-
 include/linux/bio.h       | 5 -----
 include/linux/blk_types.h | 1 +
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/bio.c b/fs/bio.c
index e545a44..9238a54 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -252,7 +252,7 @@ static void bio_free(struct bio *bio)
 	__bio_free(bio);
 
 	if (bs) {
-		if (bio_has_allocated_vec(bio))
+		if (bio_flagged(bio, BIO_OWNS_VEC))
 			bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
 
 		/*
@@ -451,6 +451,8 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 
 		if (unlikely(!bvl))
 			goto err_free;
+
+		bio->bi_flags |= 1 << BIO_OWNS_VEC;
 	} else if (nr_iovecs) {
 		bvl = bio->bi_inline_vecs;
 	}
diff --git a/include/linux/bio.h b/include/linux/bio.h
index e25378f..794bcd0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -85,11 +85,6 @@ static inline void *bio_data(struct bio *bio)
 	return NULL;
 }
 
-static inline int bio_has_allocated_vec(struct bio *bio)
-{
-	return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
-}
-
 /*
  * will die
  */
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index c178d25..538289f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -117,6 +117,7 @@ struct bio {
  * BIO_POOL_IDX()
  */
 #define BIO_RESET_BITS	12
+#define BIO_OWNS_VEC	12	/* bio_free() should free bvec */
 
 #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
 
-- 
1.7.12

[PATCH 27/27] bio-integrity: Add explicit field for owner of bip_buf

[Kent Overstreet]

This was the only real user of BIO_CLONED, which didn't have very clear
semantics. Convert to its own flag so we can get rid of BIO_CLONED.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
---
 fs/bio-integrity.c  | 5 ++---
 include/linux/bio.h | 1 +
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index ca7b02d..8fb4291 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -97,9 +97,7 @@ void bio_integrity_free(struct bio *bio)
 	struct bio_integrity_payload *bip = bio->bi_integrity;
 	struct bio_set *bs = bio->bi_pool;
 
-	/* A cloned bio doesn't own the integrity metadata */
-	if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
-	    && bip->bip_buf != NULL)
+	if (bip->bip_owns_buf)
 		kfree(bip->bip_buf);
 
 	if (bs) {
@@ -386,6 +384,7 @@ int bio_integrity_prep(struct bio *bio)
 		return -EIO;
 	}
 
+	bip->bip_owns_buf = 1;
 	bip->bip_buf = buf;
 	bip->bip_size = len;
 	bip->bip_sector = bio->bi_sector;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 794bcd0..ef24466 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -187,6 +187,7 @@ struct bio_integrity_payload {
 	unsigned short		bip_slab;	/* slab the bip came from */
 	unsigned short		bip_vcnt;	/* # of integrity bio_vecs */
 	unsigned short		bip_idx;	/* current bip_vec index */
+	unsigned		bip_owns_buf:1;	/* should free bip_buf */
 
 	struct work_struct	bip_work;	/* I/O completion */
 
-- 
1.7.12

Re: [PATCH 09/27] block: Use bio_sectors() more consistently

[Ed Cashin]

That looks OK to me.

(I notice that while back in October it included changes to aoe, the current patch does not, which is fine.)

On Feb 19, 2013, at 7:22 PM, Kent Overstreet wrote:

> Bunch of places in the code weren't using it where they could be -
> this'll reduce the size of the patch that puts bi_sector/bi_size/bi_idx
> into a struct bvec_iter.
> 
> Signed-off-by: Kent Overstreet <koverstreet@google.com>
> CC: Jens Axboe <axboe@kernel.dk>
> CC: "Ed L. Cashin" <ecashin@coraid.com>
> CC: Nick Piggin <npiggin@kernel.dk>
> CC: Jiri Kosina <jkosina@suse.cz>
> CC: Jim Paris <jim@jtan.com>
> CC: Geoff Levand <geoff@infradead.org>
> CC: Alasdair Kergon <agk@redhat.com>
> CC: dm-devel@redhat.com
> CC: Neil Brown <neilb@suse.de>
> CC: Steven Rostedt <rostedt@goodmis.org>
> Acked-by: Ed Cashin <ecashin@coraid.com>
> ---
> drivers/block/pktcdvd.c      |  2 +-
> drivers/md/dm-raid1.c        |  2 +-
> drivers/md/raid0.c           |  6 +++---
> drivers/md/raid1.c           | 17 ++++++++---------
> drivers/md/raid10.c          | 24 +++++++++++-------------
> drivers/md/raid5.c           |  8 ++++----
> fs/btrfs/volumes.c           |  2 +-
> include/trace/events/block.h | 12 ++++++------
> 8 files changed, 35 insertions(+), 38 deletions(-)
...

-- 
  Ed Cashin
  ecashin@coraid.com

Re: [PATCH 26/27] block: Add an explicit bio flag for bios that own their bvec

[Andrew Morton]

On Tue, 19 Feb 2013 16:22:40 -0800 Kent Overstreet <koverstreet@google.com> wrote:

> This is for the new bio splitting code. When we split a bio, if the
> split occured on a bvec boundry we reuse the bvec for the new bio. But
> that means bio_free() can't free it, hence the explicit flag.
> 
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -117,6 +117,7 @@ struct bio {
>   * BIO_POOL_IDX()
>   */
>  #define BIO_RESET_BITS	12
> +#define BIO_OWNS_VEC	12	/* bio_free() should free bvec */
>  
>  #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))

The BIO_OWNS_VEC definition seems to be in the wrong place - it should
be grouped with the "bio flags" group above?

Re: [PATCH 26/27] block: Add an explicit bio flag for bios that own their bvec

[Kent Overstreet]

On Tue, Mar 26, 2013 at 11:11:06AM -0700, Andrew Morton wrote:
> On Tue, 19 Feb 2013 16:22:40 -0800 Kent Overstreet <koverstreet@google.com> wrote:
> 
> > This is for the new bio splitting code. When we split a bio, if the
> > split occured on a bvec boundry we reuse the bvec for the new bio. But
> > that means bio_free() can't free it, hence the explicit flag.
> > 
> > --- a/include/linux/blk_types.h
> > +++ b/include/linux/blk_types.h
> > @@ -117,6 +117,7 @@ struct bio {
> >   * BIO_POOL_IDX()
> >   */
> >  #define BIO_RESET_BITS	12
> > +#define BIO_OWNS_VEC	12	/* bio_free() should free bvec */
> >  
> >  #define bio_flagged(bio, flag)	((bio)->bi_flags & (1 << (flag)))
> 
> The BIO_OWNS_VEC definition seems to be in the wrong place - it should
> be grouped with the "bio flags" group above?

No - BIO_OWNS_VEC is set by bio_alloc_bioset() and is used by bio_free()
to determine if it should free the biovec, so it's something we don't
want cleared if driver code uses bio_reset().

Re: [PATCH 04/27] block: Convert integrity to bvec_alloc_bs()

[Bjorn Helgaas]

On Tue, Feb 19, 2013 at 4:22 PM, Kent Overstreet <koverstreet@google.com> wrote:

> diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
> index 94fa1c5..8c4c604 100644
> --- a/fs/bio-integrity.c
> +++ b/fs/bio-integrity.c
> ...
> @@ -766,13 +733,14 @@ void bioset_integrity_free(struct bio_set *bs)
>  {
>         if (bs->bio_integrity_pool)
>                 mempool_destroy(bs->bio_integrity_pool);
> +
> +       if (bs->bvec_integrity_pool)
> +               mempool_destroy(bs->bio_integrity_pool);

I think this is a copy-and-paste error that results in using
bs->bio_integrity_pool after it has been freed.  Found by Coverity
(CID 1020654).

>  }
>  EXPORT_SYMBOL(bioset_integrity_free);