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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 09-05-2012, 08:27 PM
Kent Overstreet
 
Default block: Generalized bio pool freeing

With the old code, when you allocate a bio from a bio pool you have to
implement your own destructor that knows how to find the bio pool the
bio was originally allocated from.

This adds a new field to struct bio (bi_pool) and changes
bio_alloc_bioset() to use it. This makes various bio destructors
unnecessary, so they're then deleted.

v6: Explain the temporary if statement in bio_put

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: Nicholas Bellinger <nab@linux-iscsi.org>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/block/drbd/drbd_main.c | 13 +------------
drivers/md/dm-crypt.c | 9 ---------
drivers/md/dm-io.c | 11 -----------
drivers/md/dm.c | 20 --------------------
drivers/md/md.c | 28 ++++------------------------
drivers/target/target_core_iblock.c | 9 ---------
fs/bio.c | 31 +++++++++++++------------------
include/linux/blk_types.h | 3 +++
8 files changed, 21 insertions(+), 103 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index f93a032..f55683a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -162,23 +162,12 @@ static const struct block_device_operations drbd_ops = {
.release = drbd_release,
};

-static void bio_destructor_drbd(struct bio *bio)
-{
- bio_free(bio, drbd_md_io_bio_set);
-}
-
struct bio *bio_alloc_drbd(gfp_t gfp_mask)
{
- struct bio *bio;
-
if (!drbd_md_io_bio_set)
return bio_alloc(gfp_mask, 1);

- bio = bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
- if (!bio)
- return NULL;
- bio->bi_destructor = bio_destructor_drbd;
- return bio;
+ return bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
}

#ifdef __CHECKER__
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 664743d..3c0acba 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -798,14 +798,6 @@ static int crypt_convert(struct crypt_config *cc,
return 0;
}

-static void dm_crypt_bio_destructor(struct bio *bio)
-{
- struct dm_crypt_io *io = bio->bi_private;
- struct crypt_config *cc = io->cc;
-
- bio_free(bio, cc->bs);
-}
-
/*
* Generate a new unfragmented bio with the given size
* This should never violate the device limitations
@@ -974,7 +966,6 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
clone->bi_end_io = crypt_endio;
clone->bi_bdev = cc->dev->bdev;
clone->bi_rw = io->base_bio->bi_rw;
- clone->bi_destructor = dm_crypt_bio_destructor;
}

static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ea5dd28..1c46f97 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -249,16 +249,6 @@ static void vm_dp_init(struct dpages *dp, void *data)
dp->context_ptr = data;
}

-static void dm_bio_destructor(struct bio *bio)
-{
- unsigned region;
- struct io *io;
-
- retrieve_io_and_region_from_bio(bio, &io, &region);
-
- bio_free(bio, io->client->bios);
-}
-
/*
* Functions for getting the pages from kernel memory.
*/
@@ -317,7 +307,6 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
- bio->bi_destructor = dm_bio_destructor;
store_io_and_region_in_bio(bio, io, region);

if (rw & REQ_DISCARD) {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4e09b6f..0c3d6dd 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -681,11 +681,6 @@ static void clone_endio(struct bio *bio, int error)
}
}

- /*
- * Store md for cleanup instead of tio which is about to get freed.
- */
- bio->bi_private = md->bs;
-
free_tio(md, tio);
bio_put(bio);
dec_pending(io, error);
@@ -1032,11 +1027,6 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
/* error the io and bail out, or requeue it if needed */
md = tio->io->md;
dec_pending(tio->io, r);
- /*
- * Store bio_set for cleanup.
- */
- clone->bi_end_io = NULL;
- clone->bi_private = md->bs;
bio_put(clone);
free_tio(md, tio);
} else if (r) {
@@ -1055,13 +1045,6 @@ struct clone_info {
unsigned short idx;
};

-static void dm_bio_destructor(struct bio *bio)
-{
- struct bio_set *bs = bio->bi_private;
-
- bio_free(bio, bs);
-}
-
/*
* Creates a little bio that just does part of a bvec.
*/
@@ -1073,7 +1056,6 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
struct bio_vec *bv = bio->bi_io_vec + idx;

clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
- clone->bi_destructor = dm_bio_destructor;
*clone->bi_io_vec = *bv;

clone->bi_sector = sector;
@@ -1105,7 +1087,6 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,

clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
__bio_clone(clone, bio);
- clone->bi_destructor = dm_bio_destructor;
clone->bi_sector = sector;
clone->bi_idx = idx;
clone->bi_vcnt = idx + bv_count;
@@ -1150,7 +1131,6 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
*/
clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
__bio_clone(clone, ci->bio);
- clone->bi_destructor = dm_bio_destructor;
if (len) {
clone->bi_sector = ci->sector;
clone->bi_size = to_bytes(len);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3f6203a..b8eebe3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -155,32 +155,17 @@ static int start_readonly;
* like bio_clone, but with a local bio set
*/

-static void mddev_bio_destructor(struct bio *bio)
-{
- struct mddev *mddev, **mddevp;
-
- mddevp = (void*)bio;
- mddev = mddevp[-1];
-
- bio_free(bio, mddev->bio_set);
-}
-
struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_alloc(gfp_mask, nr_iovecs);

- b = bio_alloc_bioset(gfp_mask, nr_iovecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, nr_iovecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
return b;
}
EXPORT_SYMBOL_GPL(bio_alloc_mddev);
@@ -189,18 +174,14 @@ struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_clone(bio, gfp_mask);

- b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
+
__bio_clone(b, bio);
if (bio_integrity(bio)) {
int ret;
@@ -5006,8 +4987,7 @@ int md_run(struct mddev *mddev)
}

if (mddev->bio_set == NULL)
- mddev->bio_set = bioset_create(BIO_POOL_SIZE,
- sizeof(struct mddev *));
+ mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0);

spin_lock(&pers_lock);
pers = find_pers(mddev->level, mddev->clevel);
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 76db75e..e58cd7d 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -543,14 +543,6 @@ static void iblock_complete_cmd(struct se_cmd *cmd)
kfree(ibr);
}

-static void iblock_bio_destructor(struct bio *bio)
-{
- struct se_cmd *cmd = bio->bi_private;
- struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
-
- bio_free(bio, ib_dev->ibd_bio_set);
-}
-
static struct bio *
iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
{
@@ -572,7 +564,6 @@ iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)

bio->bi_bdev = ib_dev->ibd_bd;
bio->bi_private = cmd;
- bio->bi_destructor = iblock_bio_destructor;
bio->bi_end_io = &iblock_bio_done;
bio->bi_sector = lba;
return bio;
diff --git a/fs/bio.c b/fs/bio.c
index 71072ab..e017f7a 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -272,10 +272,6 @@ EXPORT_SYMBOL(bio_init);
* bio_alloc_bioset will try its own mempool to satisfy the allocation.
* If %__GFP_WAIT is set then we will block on the internal pool waiting
* for a &struct bio to become free.
- *
- * Note that the caller must set ->bi_destructor on successful return
- * of a bio, to do the appropriate freeing of the bio once the reference
- * count drops to zero.
**/
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
@@ -290,6 +286,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
bio = p + bs->front_pad;

bio_init(bio);
+ bio->bi_pool = bs;

if (unlikely(!nr_iovecs))
goto out_set;
@@ -316,11 +313,6 @@ err_free:
}
EXPORT_SYMBOL(bio_alloc_bioset);

-static void bio_fs_destructor(struct bio *bio)
-{
- bio_free(bio, fs_bio_set);
-}
-
/**
* bio_alloc - allocate a new bio, memory pool backed
* @gfp_mask: allocation mask to use
@@ -342,12 +334,7 @@ static void bio_fs_destructor(struct bio *bio)
*/
struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
- struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
-
- if (bio)
- bio->bi_destructor = bio_fs_destructor;
-
- return bio;
+ return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
}
EXPORT_SYMBOL(bio_alloc);

@@ -423,7 +410,16 @@ void bio_put(struct bio *bio)
if (atomic_dec_and_test(&bio->bi_cnt)) {
bio_disassociate_task(bio);
bio->bi_next = NULL;
- bio->bi_destructor(bio);
+
+ /*
+ * This if statement is temporary - bi_pool is replacing
+ * bi_destructor, but bi_destructor will be taken out in another
+ * patch.
+ */
+ if (bio->bi_pool)
+ bio_free(bio, bio->bi_pool);
+ else
+ bio->bi_destructor(bio);
}
}
EXPORT_SYMBOL(bio_put);
@@ -474,12 +470,11 @@ EXPORT_SYMBOL(__bio_clone);
*/
struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
+ struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);

if (!b)
return NULL;

- b->bi_destructor = bio_fs_destructor;
__bio_clone(b, bio);

if (bio_integrity(bio)) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7b7ac9c..af9dd9d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -80,6 +80,9 @@ struct bio {
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif

+ /* If bi_pool is non NULL, bi_destructor is not called */
+ struct bio_set *bi_pool;
+
bio_destructor_t *bi_destructor; /* destructor */

/*
--
1.7.12

--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel
 
Old 09-06-2012, 09:32 PM
Kent Overstreet
 
Default block: Generalized bio pool freeing

With the old code, when you allocate a bio from a bio pool you have to
implement your own destructor that knows how to find the bio pool the
bio was originally allocated from.

This adds a new field to struct bio (bi_pool) and changes
bio_alloc_bioset() to use it. This makes various bio destructors
unnecessary, so they're then deleted.

v6: Explain the temporary if statement in bio_put

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: Nicholas Bellinger <nab@linux-iscsi.org>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/block/drbd/drbd_main.c | 13 +------------
drivers/md/dm-crypt.c | 9 ---------
drivers/md/dm-io.c | 11 -----------
drivers/md/dm.c | 20 --------------------
drivers/md/md.c | 28 ++++------------------------
drivers/target/target_core_iblock.c | 9 ---------
fs/bio.c | 31 +++++++++++++------------------
include/linux/blk_types.h | 3 +++
8 files changed, 21 insertions(+), 103 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index f93a032..f55683a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -162,23 +162,12 @@ static const struct block_device_operations drbd_ops = {
.release = drbd_release,
};

-static void bio_destructor_drbd(struct bio *bio)
-{
- bio_free(bio, drbd_md_io_bio_set);
-}
-
struct bio *bio_alloc_drbd(gfp_t gfp_mask)
{
- struct bio *bio;
-
if (!drbd_md_io_bio_set)
return bio_alloc(gfp_mask, 1);

- bio = bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
- if (!bio)
- return NULL;
- bio->bi_destructor = bio_destructor_drbd;
- return bio;
+ return bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
}

#ifdef __CHECKER__
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 664743d..3c0acba 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -798,14 +798,6 @@ static int crypt_convert(struct crypt_config *cc,
return 0;
}

-static void dm_crypt_bio_destructor(struct bio *bio)
-{
- struct dm_crypt_io *io = bio->bi_private;
- struct crypt_config *cc = io->cc;
-
- bio_free(bio, cc->bs);
-}
-
/*
* Generate a new unfragmented bio with the given size
* This should never violate the device limitations
@@ -974,7 +966,6 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
clone->bi_end_io = crypt_endio;
clone->bi_bdev = cc->dev->bdev;
clone->bi_rw = io->base_bio->bi_rw;
- clone->bi_destructor = dm_crypt_bio_destructor;
}

static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ea5dd28..1c46f97 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -249,16 +249,6 @@ static void vm_dp_init(struct dpages *dp, void *data)
dp->context_ptr = data;
}

-static void dm_bio_destructor(struct bio *bio)
-{
- unsigned region;
- struct io *io;
-
- retrieve_io_and_region_from_bio(bio, &io, &region);
-
- bio_free(bio, io->client->bios);
-}
-
/*
* Functions for getting the pages from kernel memory.
*/
@@ -317,7 +307,6 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
- bio->bi_destructor = dm_bio_destructor;
store_io_and_region_in_bio(bio, io, region);

if (rw & REQ_DISCARD) {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4e09b6f..0c3d6dd 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -681,11 +681,6 @@ static void clone_endio(struct bio *bio, int error)
}
}

- /*
- * Store md for cleanup instead of tio which is about to get freed.
- */
- bio->bi_private = md->bs;
-
free_tio(md, tio);
bio_put(bio);
dec_pending(io, error);
@@ -1032,11 +1027,6 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
/* error the io and bail out, or requeue it if needed */
md = tio->io->md;
dec_pending(tio->io, r);
- /*
- * Store bio_set for cleanup.
- */
- clone->bi_end_io = NULL;
- clone->bi_private = md->bs;
bio_put(clone);
free_tio(md, tio);
} else if (r) {
@@ -1055,13 +1045,6 @@ struct clone_info {
unsigned short idx;
};

-static void dm_bio_destructor(struct bio *bio)
-{
- struct bio_set *bs = bio->bi_private;
-
- bio_free(bio, bs);
-}
-
/*
* Creates a little bio that just does part of a bvec.
*/
@@ -1073,7 +1056,6 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
struct bio_vec *bv = bio->bi_io_vec + idx;

clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
- clone->bi_destructor = dm_bio_destructor;
*clone->bi_io_vec = *bv;

clone->bi_sector = sector;
@@ -1105,7 +1087,6 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,

clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
__bio_clone(clone, bio);
- clone->bi_destructor = dm_bio_destructor;
clone->bi_sector = sector;
clone->bi_idx = idx;
clone->bi_vcnt = idx + bv_count;
@@ -1150,7 +1131,6 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
*/
clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
__bio_clone(clone, ci->bio);
- clone->bi_destructor = dm_bio_destructor;
if (len) {
clone->bi_sector = ci->sector;
clone->bi_size = to_bytes(len);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3f6203a..b8eebe3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -155,32 +155,17 @@ static int start_readonly;
* like bio_clone, but with a local bio set
*/

-static void mddev_bio_destructor(struct bio *bio)
-{
- struct mddev *mddev, **mddevp;
-
- mddevp = (void*)bio;
- mddev = mddevp[-1];
-
- bio_free(bio, mddev->bio_set);
-}
-
struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_alloc(gfp_mask, nr_iovecs);

- b = bio_alloc_bioset(gfp_mask, nr_iovecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, nr_iovecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
return b;
}
EXPORT_SYMBOL_GPL(bio_alloc_mddev);
@@ -189,18 +174,14 @@ struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_clone(bio, gfp_mask);

- b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
+
__bio_clone(b, bio);
if (bio_integrity(bio)) {
int ret;
@@ -5006,8 +4987,7 @@ int md_run(struct mddev *mddev)
}

if (mddev->bio_set == NULL)
- mddev->bio_set = bioset_create(BIO_POOL_SIZE,
- sizeof(struct mddev *));
+ mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0);

spin_lock(&pers_lock);
pers = find_pers(mddev->level, mddev->clevel);
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 76db75e..e58cd7d 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -543,14 +543,6 @@ static void iblock_complete_cmd(struct se_cmd *cmd)
kfree(ibr);
}

-static void iblock_bio_destructor(struct bio *bio)
-{
- struct se_cmd *cmd = bio->bi_private;
- struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
-
- bio_free(bio, ib_dev->ibd_bio_set);
-}
-
static struct bio *
iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
{
@@ -572,7 +564,6 @@ iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)

bio->bi_bdev = ib_dev->ibd_bd;
bio->bi_private = cmd;
- bio->bi_destructor = iblock_bio_destructor;
bio->bi_end_io = &iblock_bio_done;
bio->bi_sector = lba;
return bio;
diff --git a/fs/bio.c b/fs/bio.c
index 71072ab..e017f7a 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -272,10 +272,6 @@ EXPORT_SYMBOL(bio_init);
* bio_alloc_bioset will try its own mempool to satisfy the allocation.
* If %__GFP_WAIT is set then we will block on the internal pool waiting
* for a &struct bio to become free.
- *
- * Note that the caller must set ->bi_destructor on successful return
- * of a bio, to do the appropriate freeing of the bio once the reference
- * count drops to zero.
**/
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
@@ -290,6 +286,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
bio = p + bs->front_pad;

bio_init(bio);
+ bio->bi_pool = bs;

if (unlikely(!nr_iovecs))
goto out_set;
@@ -316,11 +313,6 @@ err_free:
}
EXPORT_SYMBOL(bio_alloc_bioset);

-static void bio_fs_destructor(struct bio *bio)
-{
- bio_free(bio, fs_bio_set);
-}
-
/**
* bio_alloc - allocate a new bio, memory pool backed
* @gfp_mask: allocation mask to use
@@ -342,12 +334,7 @@ static void bio_fs_destructor(struct bio *bio)
*/
struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
- struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
-
- if (bio)
- bio->bi_destructor = bio_fs_destructor;
-
- return bio;
+ return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
}
EXPORT_SYMBOL(bio_alloc);

@@ -423,7 +410,16 @@ void bio_put(struct bio *bio)
if (atomic_dec_and_test(&bio->bi_cnt)) {
bio_disassociate_task(bio);
bio->bi_next = NULL;
- bio->bi_destructor(bio);
+
+ /*
+ * This if statement is temporary - bi_pool is replacing
+ * bi_destructor, but bi_destructor will be taken out in another
+ * patch.
+ */
+ if (bio->bi_pool)
+ bio_free(bio, bio->bi_pool);
+ else
+ bio->bi_destructor(bio);
}
}
EXPORT_SYMBOL(bio_put);
@@ -474,12 +470,11 @@ EXPORT_SYMBOL(__bio_clone);
*/
struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
+ struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);

if (!b)
return NULL;

- b->bi_destructor = bio_fs_destructor;
__bio_clone(b, bio);

if (bio_integrity(bio)) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7b7ac9c..af9dd9d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -80,6 +80,9 @@ struct bio {
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif

+ /* If bi_pool is non NULL, bi_destructor is not called */
+ struct bio_set *bi_pool;
+
bio_destructor_t *bi_destructor; /* destructor */

/*
--
1.7.12

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Old 09-06-2012, 10:34 PM
Kent Overstreet
 
Default block: Generalized bio pool freeing

With the old code, when you allocate a bio from a bio pool you have to
implement your own destructor that knows how to find the bio pool the
bio was originally allocated from.

This adds a new field to struct bio (bi_pool) and changes
bio_alloc_bioset() to use it. This makes various bio destructors
unnecessary, so they're then deleted.

v6: Explain the temporary if statement in bio_put

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: Nicholas Bellinger <nab@linux-iscsi.org>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/block/drbd/drbd_main.c | 13 +------------
drivers/md/dm-crypt.c | 9 ---------
drivers/md/dm-io.c | 11 -----------
drivers/md/dm.c | 20 --------------------
drivers/md/md.c | 28 ++++------------------------
drivers/target/target_core_iblock.c | 9 ---------
fs/bio.c | 31 +++++++++++++------------------
include/linux/blk_types.h | 3 +++
8 files changed, 21 insertions(+), 103 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index f93a032..f55683a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -162,23 +162,12 @@ static const struct block_device_operations drbd_ops = {
.release = drbd_release,
};

-static void bio_destructor_drbd(struct bio *bio)
-{
- bio_free(bio, drbd_md_io_bio_set);
-}
-
struct bio *bio_alloc_drbd(gfp_t gfp_mask)
{
- struct bio *bio;
-
if (!drbd_md_io_bio_set)
return bio_alloc(gfp_mask, 1);

- bio = bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
- if (!bio)
- return NULL;
- bio->bi_destructor = bio_destructor_drbd;
- return bio;
+ return bio_alloc_bioset(gfp_mask, 1, drbd_md_io_bio_set);
}

#ifdef __CHECKER__
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 664743d..3c0acba 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -798,14 +798,6 @@ static int crypt_convert(struct crypt_config *cc,
return 0;
}

-static void dm_crypt_bio_destructor(struct bio *bio)
-{
- struct dm_crypt_io *io = bio->bi_private;
- struct crypt_config *cc = io->cc;
-
- bio_free(bio, cc->bs);
-}
-
/*
* Generate a new unfragmented bio with the given size
* This should never violate the device limitations
@@ -974,7 +966,6 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
clone->bi_end_io = crypt_endio;
clone->bi_bdev = cc->dev->bdev;
clone->bi_rw = io->base_bio->bi_rw;
- clone->bi_destructor = dm_crypt_bio_destructor;
}

static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ea5dd28..1c46f97 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -249,16 +249,6 @@ static void vm_dp_init(struct dpages *dp, void *data)
dp->context_ptr = data;
}

-static void dm_bio_destructor(struct bio *bio)
-{
- unsigned region;
- struct io *io;
-
- retrieve_io_and_region_from_bio(bio, &io, &region);
-
- bio_free(bio, io->client->bios);
-}
-
/*
* Functions for getting the pages from kernel memory.
*/
@@ -317,7 +307,6 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
- bio->bi_destructor = dm_bio_destructor;
store_io_and_region_in_bio(bio, io, region);

if (rw & REQ_DISCARD) {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4e09b6f..0c3d6dd 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -681,11 +681,6 @@ static void clone_endio(struct bio *bio, int error)
}
}

- /*
- * Store md for cleanup instead of tio which is about to get freed.
- */
- bio->bi_private = md->bs;
-
free_tio(md, tio);
bio_put(bio);
dec_pending(io, error);
@@ -1032,11 +1027,6 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
/* error the io and bail out, or requeue it if needed */
md = tio->io->md;
dec_pending(tio->io, r);
- /*
- * Store bio_set for cleanup.
- */
- clone->bi_end_io = NULL;
- clone->bi_private = md->bs;
bio_put(clone);
free_tio(md, tio);
} else if (r) {
@@ -1055,13 +1045,6 @@ struct clone_info {
unsigned short idx;
};

-static void dm_bio_destructor(struct bio *bio)
-{
- struct bio_set *bs = bio->bi_private;
-
- bio_free(bio, bs);
-}
-
/*
* Creates a little bio that just does part of a bvec.
*/
@@ -1073,7 +1056,6 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
struct bio_vec *bv = bio->bi_io_vec + idx;

clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
- clone->bi_destructor = dm_bio_destructor;
*clone->bi_io_vec = *bv;

clone->bi_sector = sector;
@@ -1105,7 +1087,6 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector,

clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
__bio_clone(clone, bio);
- clone->bi_destructor = dm_bio_destructor;
clone->bi_sector = sector;
clone->bi_idx = idx;
clone->bi_vcnt = idx + bv_count;
@@ -1150,7 +1131,6 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
*/
clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
__bio_clone(clone, ci->bio);
- clone->bi_destructor = dm_bio_destructor;
if (len) {
clone->bi_sector = ci->sector;
clone->bi_size = to_bytes(len);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3f6203a..b8eebe3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -155,32 +155,17 @@ static int start_readonly;
* like bio_clone, but with a local bio set
*/

-static void mddev_bio_destructor(struct bio *bio)
-{
- struct mddev *mddev, **mddevp;
-
- mddevp = (void*)bio;
- mddev = mddevp[-1];
-
- bio_free(bio, mddev->bio_set);
-}
-
struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_alloc(gfp_mask, nr_iovecs);

- b = bio_alloc_bioset(gfp_mask, nr_iovecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, nr_iovecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
return b;
}
EXPORT_SYMBOL_GPL(bio_alloc_mddev);
@@ -189,18 +174,14 @@ struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
struct mddev *mddev)
{
struct bio *b;
- struct mddev **mddevp;

if (!mddev || !mddev->bio_set)
return bio_clone(bio, gfp_mask);

- b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
- mddev->bio_set);
+ b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, mddev->bio_set);
if (!b)
return NULL;
- mddevp = (void*)b;
- mddevp[-1] = mddev;
- b->bi_destructor = mddev_bio_destructor;
+
__bio_clone(b, bio);
if (bio_integrity(bio)) {
int ret;
@@ -5006,8 +4987,7 @@ int md_run(struct mddev *mddev)
}

if (mddev->bio_set == NULL)
- mddev->bio_set = bioset_create(BIO_POOL_SIZE,
- sizeof(struct mddev *));
+ mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0);

spin_lock(&pers_lock);
pers = find_pers(mddev->level, mddev->clevel);
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 76db75e..e58cd7d 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -543,14 +543,6 @@ static void iblock_complete_cmd(struct se_cmd *cmd)
kfree(ibr);
}

-static void iblock_bio_destructor(struct bio *bio)
-{
- struct se_cmd *cmd = bio->bi_private;
- struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
-
- bio_free(bio, ib_dev->ibd_bio_set);
-}
-
static struct bio *
iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
{
@@ -572,7 +564,6 @@ iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)

bio->bi_bdev = ib_dev->ibd_bd;
bio->bi_private = cmd;
- bio->bi_destructor = iblock_bio_destructor;
bio->bi_end_io = &iblock_bio_done;
bio->bi_sector = lba;
return bio;
diff --git a/fs/bio.c b/fs/bio.c
index 71072ab..e017f7a 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -272,10 +272,6 @@ EXPORT_SYMBOL(bio_init);
* bio_alloc_bioset will try its own mempool to satisfy the allocation.
* If %__GFP_WAIT is set then we will block on the internal pool waiting
* for a &struct bio to become free.
- *
- * Note that the caller must set ->bi_destructor on successful return
- * of a bio, to do the appropriate freeing of the bio once the reference
- * count drops to zero.
**/
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
@@ -290,6 +286,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
bio = p + bs->front_pad;

bio_init(bio);
+ bio->bi_pool = bs;

if (unlikely(!nr_iovecs))
goto out_set;
@@ -316,11 +313,6 @@ err_free:
}
EXPORT_SYMBOL(bio_alloc_bioset);

-static void bio_fs_destructor(struct bio *bio)
-{
- bio_free(bio, fs_bio_set);
-}
-
/**
* bio_alloc - allocate a new bio, memory pool backed
* @gfp_mask: allocation mask to use
@@ -342,12 +334,7 @@ static void bio_fs_destructor(struct bio *bio)
*/
struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
- struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
-
- if (bio)
- bio->bi_destructor = bio_fs_destructor;
-
- return bio;
+ return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
}
EXPORT_SYMBOL(bio_alloc);

@@ -423,7 +410,16 @@ void bio_put(struct bio *bio)
if (atomic_dec_and_test(&bio->bi_cnt)) {
bio_disassociate_task(bio);
bio->bi_next = NULL;
- bio->bi_destructor(bio);
+
+ /*
+ * This if statement is temporary - bi_pool is replacing
+ * bi_destructor, but bi_destructor will be taken out in another
+ * patch.
+ */
+ if (bio->bi_pool)
+ bio_free(bio, bio->bi_pool);
+ else
+ bio->bi_destructor(bio);
}
}
EXPORT_SYMBOL(bio_put);
@@ -474,12 +470,11 @@ EXPORT_SYMBOL(__bio_clone);
*/
struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
{
- struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
+ struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);

if (!b)
return NULL;

- b->bi_destructor = bio_fs_destructor;
__bio_clone(b, bio);

if (bio_integrity(bio)) {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7b7ac9c..af9dd9d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -80,6 +80,9 @@ struct bio {
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif

+ /* If bi_pool is non NULL, bi_destructor is not called */
+ struct bio_set *bi_pool;
+
bio_destructor_t *bi_destructor; /* destructor */

/*
--
1.7.12

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Old 09-14-2012, 06:28 PM
Alasdair G Kergon
 
Default block: Generalized bio pool freeing

On Thu, Sep 06, 2012 at 03:34:55PM -0700, Kent Overstreet wrote:
> With the old code, when you allocate a bio from a bio pool you have to
> implement your own destructor that knows how to find the bio pool the
> bio was originally allocated from.
>
> This adds a new field to struct bio (bi_pool) and changes
> bio_alloc_bioset() to use it. This makes various bio destructors
> unnecessary, so they're then deleted.
>
> v6: Explain the temporary if statement in bio_put

This patch also silently reverts
commit 4d7b38b7d944a79da3793b6c92d38682f3905ac9
"dm: clear bi_end_io on remapping failure"

Why?

If it's intentional, please explain it in your patch header and
copy Hannes to reconsider the matter.

If it wasn't intentional, please reinstate it.

Alasdair

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Old 09-14-2012, 06:36 PM
Alasdair G Kergon
 
Default block: Generalized bio pool freeing

On Thu, Sep 06, 2012 at 03:34:55PM -0700, Kent Overstreet wrote:
> With the old code, when you allocate a bio from a bio pool you have to
> implement your own destructor that knows how to find the bio pool the
> bio was originally allocated from.
> This adds a new field to struct bio (bi_pool) and changes
> bio_alloc_bioset() to use it. This makes various bio destructors
> unnecessary, so they're then deleted.

If you reinstate commit 4d7b38b7d944a79da3793b6c92d38682f3905ac9
"dm: clear bi_end_io on remapping failure",

Acked-by: Alasdair Kergon <agk@redhat.com>

for the device-mapper parts.

Alasdair

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Old 09-17-2012, 08:51 PM
Kent Overstreet
 
Default block: Generalized bio pool freeing

On Fri, Sep 14, 2012 at 07:28:28PM +0100, Alasdair G Kergon wrote:
> On Thu, Sep 06, 2012 at 03:34:55PM -0700, Kent Overstreet wrote:
> > With the old code, when you allocate a bio from a bio pool you have to
> > implement your own destructor that knows how to find the bio pool the
> > bio was originally allocated from.
> >
> > This adds a new field to struct bio (bi_pool) and changes
> > bio_alloc_bioset() to use it. This makes various bio destructors
> > unnecessary, so they're then deleted.
> >
> > v6: Explain the temporary if statement in bio_put
>
> This patch also silently reverts
> commit 4d7b38b7d944a79da3793b6c92d38682f3905ac9
> "dm: clear bi_end_io on remapping failure"
>
> Why?
>
> If it's intentional, please explain it in your patch header and
> copy Hannes to reconsider the matter.

Never noticed that was introduced in its own patch until you pointed it
out.

That isn't a very good patch - it says it's clearing bi_end_io as a
precaution, but as a precaution to what?

As far as I can tell, it was never necessary. The bio is about to be
freed - there shouldn't be any other references on it (__bio_map() is
called on freshly allocated bios, and bio_get() is never called in dm.c)
Nothing else should've been looking at bi_end_io, certainly the
destructor didn't.

Now that there's no destructor, it makes even less sense to have it -
after that bio_put() that bio isn't being touched by dm code anymore.

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Old 09-18-2012, 04:31 PM
Alasdair G Kergon
 
Default block: Generalized bio pool freeing

On Mon, Sep 17, 2012 at 01:51:39PM -0700, Kent Overstreet wrote:
> That isn't a very good patch - it says it's clearing bi_end_io as a
> precaution, but as a precaution to what?

As a precaution against the endio function being called an extra time by
mistake if a stray reference remains after the bio has been freed.
Wipe this field when dm frees it. Defensive programming, basically,
in response to a tricky bug he had to deal with.

Alasdair

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