+++ /dev/null
-From foo@baz Thu Mar 22 14:26:48 CET 2018
-From: NeilBrown <neilb@suse.com>
-Date: Wed, 6 Sep 2017 09:43:28 +1000
-Subject: dm: ensure bio submission follows a depth-first tree walk
-
-From: NeilBrown <neilb@suse.com>
-
-
-[ Upstream commit 18a25da84354c6bb655320de6072c00eda6eb602 ]
-
-A dm device can, in general, represent a tree of targets, each of which
-handles a sub-range of the range of blocks handled by the parent.
-
-The bio sequencing managed by generic_make_request() requires that bios
-are generated and handled in a depth-first manner. Each call to a
-make_request_fn() may submit bios to a single member device, and may
-submit bios for a reduced region of the same device as the
-make_request_fn.
-
-In particular, any bios submitted to member devices must be expected to
-be processed in order, so a later one must never wait for an earlier
-one.
-
-This ordering is usually achieved by using bio_split() to reduce a bio
-to a size that can be completely handled by one target, and resubmitting
-the remainder to the originating device. bio_queue_split() shows the
-canonical approach.
-
-dm doesn't follow this approach, largely because it has needed to split
-bios since long before bio_split() was available. It currently can
-submit bios to separate targets within the one dm_make_request() call.
-Dependencies between these targets, as can happen with dm-snap, can
-cause deadlocks if either bios gets stuck behind the other in the queues
-managed by generic_make_request(). This requires the 'rescue'
-functionality provided by dm_offload_{start,end}.
-
-Some of this requirement can be removed by changing the order of bio
-submission to follow the canonical approach. That is, if dm finds that
-it needs to split a bio, the remainder should be sent to
-generic_make_request() rather than being handled immediately. This
-delays the handling until the first part is completely processed, so the
-deadlock problems do not occur.
-
-__split_and_process_bio() can be called both from dm_make_request() and
-from dm_wq_work(). When called from dm_wq_work() the current approach
-is perfectly satisfactory as each bio will be processed immediately.
-When called from dm_make_request(), current->bio_list will be non-NULL,
-and in this case it is best to create a separate "clone" bio for the
-remainder.
-
-When we use bio_clone_bioset() to split off the front part of a bio
-and chain the two together and submit the remainder to
-generic_make_request(), it is important that the newly allocated
-bio is used as the head to be processed immediately, and the original
-bio gets "bio_advance()"d and sent to generic_make_request() as the
-remainder. Otherwise, if the newly allocated bio is used as the
-remainder, and if it then needs to be split again, then the next
-bio_clone_bioset() call will be made while holding a reference a bio
-(result of the first clone) from the same bioset. This can potentially
-exhaust the bioset mempool and result in a memory allocation deadlock.
-
-Note that there is no race caused by reassigning cio.io->bio after already
-calling __map_bio(). This bio will only be dereferenced again after
-dec_pending() has found io->io_count to be zero, and this cannot happen
-before the dec_pending() call at the end of __split_and_process_bio().
-
-To provide the clone bio when splitting, we use q->bio_split. This
-was previously being freed by bio-based dm to avoid having excess
-rescuer threads. As bio_split bio sets no longer create rescuer
-threads, there is little cost and much gain from restoring the
-q->bio_split bio set.
-
-Signed-off-by: NeilBrown <neilb@suse.com>
-Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- drivers/md/dm.c | 33 ++++++++++++++++++++++++---------
- 1 file changed, 24 insertions(+), 9 deletions(-)
-
---- a/drivers/md/dm.c
-+++ b/drivers/md/dm.c
-@@ -1497,8 +1497,29 @@ static void __split_and_process_bio(stru
- } else {
- ci.bio = bio;
- ci.sector_count = bio_sectors(bio);
-- while (ci.sector_count && !error)
-+ while (ci.sector_count && !error) {
- error = __split_and_process_non_flush(&ci);
-+ if (current->bio_list && ci.sector_count && !error) {
-+ /*
-+ * Remainder must be passed to generic_make_request()
-+ * so that it gets handled *after* bios already submitted
-+ * have been completely processed.
-+ * We take a clone of the original to store in
-+ * ci.io->bio to be used by end_io_acct() and
-+ * for dec_pending to use for completion handling.
-+ * As this path is not used for REQ_OP_ZONE_REPORT,
-+ * the usage of io->bio in dm_remap_zone_report()
-+ * won't be affected by this reassignment.
-+ */
-+ struct bio *b = bio_clone_bioset(bio, GFP_NOIO,
-+ md->queue->bio_split);
-+ ci.io->bio = b;
-+ bio_advance(bio, (bio_sectors(bio) - ci.sector_count) << 9);
-+ bio_chain(b, bio);
-+ generic_make_request(bio);
-+ break;
-+ }
-+ }
- }
-
- /* drop the extra reference count */
-@@ -1509,8 +1530,8 @@ static void __split_and_process_bio(stru
- *---------------------------------------------------------------*/
-
- /*
-- * The request function that just remaps the bio built up by
-- * dm_merge_bvec.
-+ * The request function that remaps the bio to one target and
-+ * splits off any remainder.
- */
- static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
- {
-@@ -2044,12 +2065,6 @@ int dm_setup_md_queue(struct mapped_devi
- case DM_TYPE_DAX_BIO_BASED:
- dm_init_normal_md_queue(md);
- blk_queue_make_request(md->queue, dm_make_request);
-- /*
-- * DM handles splitting bios as needed. Free the bio_split bioset
-- * since it won't be used (saves 1 process per bio-based DM device).
-- */
-- bioset_free(md->queue->bio_split);
-- md->queue->bio_split = NULL;
-
- if (type == DM_TYPE_DAX_BIO_BASED)
- queue_flag_set_unlocked(QUEUE_FLAG_DAX, md->queue);
media-c8sectpfe-fix-potential-null-pointer-dereference-in-c8sectpfe_timer_interrupt.patch
drm-msm-fix-leak-in-failed-get_pages.patch
net-fec-add-phy_reset_after_clk_enable-support.patch
-dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch
rdma-iwpm-fix-uninitialized-error-code-in-iwpm_send_mapinfo.patch
hv_netvsc-fix-the-receive-buffer-size-limit.patch
hv_netvsc-fix-the-tx-rx-buffer-default-sizes.patch
+++ /dev/null
-From foo@baz Thu Mar 22 14:03:39 CET 2018
-From: NeilBrown <neilb@suse.com>
-Date: Wed, 6 Sep 2017 09:43:28 +1000
-Subject: dm: ensure bio submission follows a depth-first tree walk
-
-From: NeilBrown <neilb@suse.com>
-
-
-[ Upstream commit 18a25da84354c6bb655320de6072c00eda6eb602 ]
-
-A dm device can, in general, represent a tree of targets, each of which
-handles a sub-range of the range of blocks handled by the parent.
-
-The bio sequencing managed by generic_make_request() requires that bios
-are generated and handled in a depth-first manner. Each call to a
-make_request_fn() may submit bios to a single member device, and may
-submit bios for a reduced region of the same device as the
-make_request_fn.
-
-In particular, any bios submitted to member devices must be expected to
-be processed in order, so a later one must never wait for an earlier
-one.
-
-This ordering is usually achieved by using bio_split() to reduce a bio
-to a size that can be completely handled by one target, and resubmitting
-the remainder to the originating device. bio_queue_split() shows the
-canonical approach.
-
-dm doesn't follow this approach, largely because it has needed to split
-bios since long before bio_split() was available. It currently can
-submit bios to separate targets within the one dm_make_request() call.
-Dependencies between these targets, as can happen with dm-snap, can
-cause deadlocks if either bios gets stuck behind the other in the queues
-managed by generic_make_request(). This requires the 'rescue'
-functionality provided by dm_offload_{start,end}.
-
-Some of this requirement can be removed by changing the order of bio
-submission to follow the canonical approach. That is, if dm finds that
-it needs to split a bio, the remainder should be sent to
-generic_make_request() rather than being handled immediately. This
-delays the handling until the first part is completely processed, so the
-deadlock problems do not occur.
-
-__split_and_process_bio() can be called both from dm_make_request() and
-from dm_wq_work(). When called from dm_wq_work() the current approach
-is perfectly satisfactory as each bio will be processed immediately.
-When called from dm_make_request(), current->bio_list will be non-NULL,
-and in this case it is best to create a separate "clone" bio for the
-remainder.
-
-When we use bio_clone_bioset() to split off the front part of a bio
-and chain the two together and submit the remainder to
-generic_make_request(), it is important that the newly allocated
-bio is used as the head to be processed immediately, and the original
-bio gets "bio_advance()"d and sent to generic_make_request() as the
-remainder. Otherwise, if the newly allocated bio is used as the
-remainder, and if it then needs to be split again, then the next
-bio_clone_bioset() call will be made while holding a reference a bio
-(result of the first clone) from the same bioset. This can potentially
-exhaust the bioset mempool and result in a memory allocation deadlock.
-
-Note that there is no race caused by reassigning cio.io->bio after already
-calling __map_bio(). This bio will only be dereferenced again after
-dec_pending() has found io->io_count to be zero, and this cannot happen
-before the dec_pending() call at the end of __split_and_process_bio().
-
-To provide the clone bio when splitting, we use q->bio_split. This
-was previously being freed by bio-based dm to avoid having excess
-rescuer threads. As bio_split bio sets no longer create rescuer
-threads, there is little cost and much gain from restoring the
-q->bio_split bio set.
-
-Signed-off-by: NeilBrown <neilb@suse.com>
-Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- drivers/md/dm.c | 33 ++++++++++++++++++++++++---------
- 1 file changed, 24 insertions(+), 9 deletions(-)
-
---- a/drivers/md/dm.c
-+++ b/drivers/md/dm.c
-@@ -1499,8 +1499,29 @@ static void __split_and_process_bio(stru
- } else {
- ci.bio = bio;
- ci.sector_count = bio_sectors(bio);
-- while (ci.sector_count && !error)
-+ while (ci.sector_count && !error) {
- error = __split_and_process_non_flush(&ci);
-+ if (current->bio_list && ci.sector_count && !error) {
-+ /*
-+ * Remainder must be passed to generic_make_request()
-+ * so that it gets handled *after* bios already submitted
-+ * have been completely processed.
-+ * We take a clone of the original to store in
-+ * ci.io->bio to be used by end_io_acct() and
-+ * for dec_pending to use for completion handling.
-+ * As this path is not used for REQ_OP_ZONE_REPORT,
-+ * the usage of io->bio in dm_remap_zone_report()
-+ * won't be affected by this reassignment.
-+ */
-+ struct bio *b = bio_clone_bioset(bio, GFP_NOIO,
-+ md->queue->bio_split);
-+ ci.io->bio = b;
-+ bio_advance(bio, (bio_sectors(bio) - ci.sector_count) << 9);
-+ bio_chain(b, bio);
-+ generic_make_request(bio);
-+ break;
-+ }
-+ }
- }
-
- /* drop the extra reference count */
-@@ -1511,8 +1532,8 @@ static void __split_and_process_bio(stru
- *---------------------------------------------------------------*/
-
- /*
-- * The request function that just remaps the bio built up by
-- * dm_merge_bvec.
-+ * The request function that remaps the bio to one target and
-+ * splits off any remainder.
- */
- static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
- {
-@@ -2035,12 +2056,6 @@ int dm_setup_md_queue(struct mapped_devi
- case DM_TYPE_DAX_BIO_BASED:
- dm_init_normal_md_queue(md);
- blk_queue_make_request(md->queue, dm_make_request);
-- /*
-- * DM handles splitting bios as needed. Free the bio_split bioset
-- * since it won't be used (saves 1 process per bio-based DM device).
-- */
-- bioset_free(md->queue->bio_split);
-- md->queue->bio_split = NULL;
-
- if (type == DM_TYPE_DAX_BIO_BASED)
- queue_flag_set_unlocked(QUEUE_FLAG_DAX, md->queue);
media-c8sectpfe-fix-potential-null-pointer-dereference-in-c8sectpfe_timer_interrupt.patch
drm-msm-fix-leak-in-failed-get_pages.patch
net-fec-add-phy_reset_after_clk_enable-support.patch
-dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch
ib-ipoib-warn-when-one-port-fails-to-initialize.patch
rdma-iwpm-fix-uninitialized-error-code-in-iwpm_send_mapinfo.patch
hv_netvsc-fix-the-receive-buffer-size-limit.patch
+++ /dev/null
-From foo@baz Thu Mar 22 14:40:24 CET 2018
-From: NeilBrown <neilb@suse.com>
-Date: Wed, 6 Sep 2017 09:43:28 +1000
-Subject: dm: ensure bio submission follows a depth-first tree walk
-
-From: NeilBrown <neilb@suse.com>
-
-
-[ Upstream commit 18a25da84354c6bb655320de6072c00eda6eb602 ]
-
-A dm device can, in general, represent a tree of targets, each of which
-handles a sub-range of the range of blocks handled by the parent.
-
-The bio sequencing managed by generic_make_request() requires that bios
-are generated and handled in a depth-first manner. Each call to a
-make_request_fn() may submit bios to a single member device, and may
-submit bios for a reduced region of the same device as the
-make_request_fn.
-
-In particular, any bios submitted to member devices must be expected to
-be processed in order, so a later one must never wait for an earlier
-one.
-
-This ordering is usually achieved by using bio_split() to reduce a bio
-to a size that can be completely handled by one target, and resubmitting
-the remainder to the originating device. bio_queue_split() shows the
-canonical approach.
-
-dm doesn't follow this approach, largely because it has needed to split
-bios since long before bio_split() was available. It currently can
-submit bios to separate targets within the one dm_make_request() call.
-Dependencies between these targets, as can happen with dm-snap, can
-cause deadlocks if either bios gets stuck behind the other in the queues
-managed by generic_make_request(). This requires the 'rescue'
-functionality provided by dm_offload_{start,end}.
-
-Some of this requirement can be removed by changing the order of bio
-submission to follow the canonical approach. That is, if dm finds that
-it needs to split a bio, the remainder should be sent to
-generic_make_request() rather than being handled immediately. This
-delays the handling until the first part is completely processed, so the
-deadlock problems do not occur.
-
-__split_and_process_bio() can be called both from dm_make_request() and
-from dm_wq_work(). When called from dm_wq_work() the current approach
-is perfectly satisfactory as each bio will be processed immediately.
-When called from dm_make_request(), current->bio_list will be non-NULL,
-and in this case it is best to create a separate "clone" bio for the
-remainder.
-
-When we use bio_clone_bioset() to split off the front part of a bio
-and chain the two together and submit the remainder to
-generic_make_request(), it is important that the newly allocated
-bio is used as the head to be processed immediately, and the original
-bio gets "bio_advance()"d and sent to generic_make_request() as the
-remainder. Otherwise, if the newly allocated bio is used as the
-remainder, and if it then needs to be split again, then the next
-bio_clone_bioset() call will be made while holding a reference a bio
-(result of the first clone) from the same bioset. This can potentially
-exhaust the bioset mempool and result in a memory allocation deadlock.
-
-Note that there is no race caused by reassigning cio.io->bio after already
-calling __map_bio(). This bio will only be dereferenced again after
-dec_pending() has found io->io_count to be zero, and this cannot happen
-before the dec_pending() call at the end of __split_and_process_bio().
-
-To provide the clone bio when splitting, we use q->bio_split. This
-was previously being freed by bio-based dm to avoid having excess
-rescuer threads. As bio_split bio sets no longer create rescuer
-threads, there is little cost and much gain from restoring the
-q->bio_split bio set.
-
-Signed-off-by: NeilBrown <neilb@suse.com>
-Signed-off-by: Mike Snitzer <snitzer@redhat.com>
-Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- drivers/md/dm.c | 33 ++++++++++++++++++++++++---------
- 1 file changed, 24 insertions(+), 9 deletions(-)
-
---- a/drivers/md/dm.c
-+++ b/drivers/md/dm.c
-@@ -1320,8 +1320,29 @@ static void __split_and_process_bio(stru
- } else {
- ci.bio = bio;
- ci.sector_count = bio_sectors(bio);
-- while (ci.sector_count && !error)
-+ while (ci.sector_count && !error) {
- error = __split_and_process_non_flush(&ci);
-+ if (current->bio_list && ci.sector_count && !error) {
-+ /*
-+ * Remainder must be passed to generic_make_request()
-+ * so that it gets handled *after* bios already submitted
-+ * have been completely processed.
-+ * We take a clone of the original to store in
-+ * ci.io->bio to be used by end_io_acct() and
-+ * for dec_pending to use for completion handling.
-+ * As this path is not used for REQ_OP_ZONE_REPORT,
-+ * the usage of io->bio in dm_remap_zone_report()
-+ * won't be affected by this reassignment.
-+ */
-+ struct bio *b = bio_clone_bioset(bio, GFP_NOIO,
-+ md->queue->bio_split);
-+ ci.io->bio = b;
-+ bio_advance(bio, (bio_sectors(bio) - ci.sector_count) << 9);
-+ bio_chain(b, bio);
-+ generic_make_request(bio);
-+ break;
-+ }
-+ }
- }
-
- /* drop the extra reference count */
-@@ -1332,8 +1353,8 @@ static void __split_and_process_bio(stru
- *---------------------------------------------------------------*/
-
- /*
-- * The request function that just remaps the bio built up by
-- * dm_merge_bvec.
-+ * The request function that remaps the bio to one target and
-+ * splits off any remainder.
- */
- static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
- {
-@@ -1854,12 +1875,6 @@ int dm_setup_md_queue(struct mapped_devi
- case DM_TYPE_DAX_BIO_BASED:
- dm_init_normal_md_queue(md);
- blk_queue_make_request(md->queue, dm_make_request);
-- /*
-- * DM handles splitting bios as needed. Free the bio_split bioset
-- * since it won't be used (saves 1 process per bio-based DM device).
-- */
-- bioset_free(md->queue->bio_split);
-- md->queue->bio_split = NULL;
-
- if (type == DM_TYPE_DAX_BIO_BASED)
- queue_flag_set_unlocked(QUEUE_FLAG_DAX, md->queue);
bluetooth-btqcomsmd-fix-skb-double-free-corruption.patch
media-c8sectpfe-fix-potential-null-pointer-dereference-in-c8sectpfe_timer_interrupt.patch
drm-msm-fix-leak-in-failed-get_pages.patch
-dm-ensure-bio-submission-follows-a-depth-first-tree-walk.patch
rdma-iwpm-fix-uninitialized-error-code-in-iwpm_send_mapinfo.patch
rtlwifi-rtl_pci-fix-the-bug-when-inactiveps-is-enabled.patch
media-bt8xx-fix-err-bt878_probe.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
