We currently only have an inline/sync helper to restart a stopped
queue. If drivers need an async version, they have to roll their
own. Add a generic helper instead.
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_queue_bio() does split then bounce, which makes the segment
counting based on pages before bouncing and could go wrong. Move
the split to after bouncing, like we do for blk-mq, and the we
fix the issue of having the bio count for segments be wrong.
Fixes: 54efd50bfd ("block: make generic_make_request handle arbitrarily sized bios")
Cc: stable@vger.kernel.org
Tested-by: Artem S. Tashkinov <t.artem@lycos.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The routines in scsi_pm.c assume that if a runtime-PM callback is
invoked for a SCSI device, it can only mean that the device's driver
has asked the block layer to handle the runtime power management (by
calling blk_pm_runtime_init(), which among other things sets q->dev).
However, this assumption turns out to be wrong for things like the ses
driver. Normally ses devices are not allowed to do runtime PM, but
userspace can override this setting. If this happens, the kernel gets
a NULL pointer dereference when blk_post_runtime_resume() tries to use
the uninitialized q->dev pointer.
This patch fixes the problem by checking q->dev in block layer before
handle runtime PM. Since ses doesn't define any PM callbacks and call
blk_pm_runtime_init(), the crash won't occur.
This fixes Bugzilla #101371.
https://bugzilla.kernel.org/show_bug.cgi?id=101371
More discussion can be found from below link.
http://marc.info/?l=linux-scsi&m=144163730531875&w=2
Signed-off-by: Ken Xue <Ken.Xue@amd.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Xiangliang Yu <Xiangliang.Yu@amd.com>
Cc: James E.J. Bottomley <JBottomley@odin.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Terry <Michael.terry@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
When a cloned request is retried on other queues it always needs
to be checked against the queue limits of that queue.
Otherwise the calculations for nr_phys_segments might be wrong,
leading to a crash in scsi_init_sgtable().
To clarify this the patch renames blk_rq_check_limits()
to blk_cloned_rq_check_limits() and removes the symbol
export, as the new function should only be used for
cloned requests and never exported.
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Fixes: e2a60da74 ("block: Clean up special command handling logic")
Cc: stable@vger.kernel.org # 3.7+
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Fix kernel-doc warning in blk-core.c:
Warning(..//block/blk-core.c:1549): No description found for parameter 'same_queue_rq'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block IO poll support from Jens Axboe:
"Various groups have been doing experimentation around IO polling for
(really) fast devices. The code has been reviewed and has been
sitting on the side for a few releases, but this is now good enough
for coordinated benchmarking and further experimentation.
Currently O_DIRECT sync read/write are supported. A framework is in
the works that allows scalable stats tracking so we can auto-tune
this. And we'll add libaio support as well soon. Fow now, it's an
opt-in feature for test purposes"
* 'for-4.4/io-poll' of git://git.kernel.dk/linux-block:
direct-io: be sure to assign dio->bio_bdev for both paths
directio: add block polling support
NVMe: add blk polling support
block: add block polling support
blk-mq: return tag/queue combo in the make_request_fn handlers
block: change ->make_request_fn() and users to return a queue cookie
Add basic support for polling for specific IO to complete. This uses
the cookie that blk-mq passes back, which enables the block layer
to pass this cookie to the driver to spin for a specific request.
This will be combined with request latency tracking, so we can make
qualified decisions about when to poll and when not to. For now, for
benchmark purposes, we add a sysfs file that controls whether polling
is enabled or not.
Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.
Signed-off-by: Jens Axboe <axboe@fb.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
__GFP_WAIT was used to signal that the caller was in atomic context and
could not sleep. Now it is possible to distinguish between true atomic
context and callers that are not willing to sleep. The latter should
clear __GFP_DIRECT_RECLAIM so kswapd will still wake. As clearing
__GFP_WAIT behaves differently, there is a risk that people will clear the
wrong flags. This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly
indicate what it does -- setting it allows all reclaim activity, clearing
them prevents it.
[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts. They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve". __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".
Over time, callers had a requirement to not block when fallback options
were available. Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.
This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative. High priority users continue to use
__GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim. __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.
This patch then converts a number of sites
o __GFP_ATOMIC is used by callers that are high priority and have memory
pools for those requests. GFP_ATOMIC uses this flag.
o Callers that have a limited mempool to guarantee forward progress clear
__GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
into this category where kswapd will still be woken but atomic reserves
are not used as there is a one-entry mempool to guarantee progress.
o Callers that are checking if they are non-blocking should use the
helper gfpflags_allow_blocking() where possible. This is because
checking for __GFP_WAIT as was done historically now can trigger false
positives. Some exceptions like dm-crypt.c exist where the code intent
is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
flag manipulations.
o Callers that built their own GFP flags instead of starting with GFP_KERNEL
and friends now also need to specify __GFP_KSWAPD_RECLAIM.
The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.
The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL. They may
now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block integrity updates from Jens Axboe:
""This is the joint work of Dan and Martin, cleaning up and improving
the support for block data integrity"
* 'for-4.4/integrity' of git://git.kernel.dk/linux-block:
block, libnvdimm, nvme: provide a built-in blk_integrity nop profile
block: blk_flush_integrity() for bio-based drivers
block: move blk_integrity to request_queue
block: generic request_queue reference counting
nvme: suspend i/o during runtime blk_integrity_unregister
md: suspend i/o during runtime blk_integrity_unregister
md, dm, scsi, nvme, libnvdimm: drop blk_integrity_unregister() at shutdown
block: Inline blk_integrity in struct gendisk
block: Export integrity data interval size in sysfs
block: Reduce the size of struct blk_integrity
block: Consolidate static integrity profile properties
block: Move integrity kobject to struct gendisk
Pull core block updates from Jens Axboe:
"This is the core block pull request for 4.4. I've got a few more
topic branches this time around, some of them will layer on top of the
core+drivers changes and will come in a separate round. So not a huge
chunk of changes in this round.
This pull request contains:
- Enable blk-mq page allocation tracking with kmemleak, from Catalin.
- Unused prototype removal in blk-mq from Christoph.
- Cleanup of the q->blk_trace exchange, using cmpxchg instead of two
xchg()'s, from Davidlohr.
- A plug flush fix from Jeff.
- Also from Jeff, a fix that means we don't have to update shared tag
sets at init time unless we do a state change. This cuts down boot
times on thousands of devices a lot with scsi/blk-mq.
- blk-mq waitqueue barrier fix from Kosuke.
- Various fixes from Ming:
- Fixes for segment merging and splitting, and checks, for
the old core and blk-mq.
- Potential blk-mq speedup by marking ctx pending at the end
of a plug insertion batch in blk-mq.
- direct-io no page dirty on kernel direct reads.
- A WRITE_SYNC fix for mpage from Roman"
* 'for-4.4/core' of git://git.kernel.dk/linux-block:
blk-mq: avoid excessive boot delays with large lun counts
blktrace: re-write setting q->blk_trace
blk-mq: mark ctx as pending at batch in flush plug path
blk-mq: fix for trace_block_plug()
block: check bio_mergeable() early before merging
blk-mq: check bio_mergeable() early before merging
block: avoid to merge splitted bio
block: setup bi_phys_segments after splitting
block: fix plug list flushing for nomerge queues
blk-mq: remove unused blk_mq_clone_flush_request prototype
blk-mq: fix waitqueue_active without memory barrier in block/blk-mq-tag.c
fs: direct-io: don't dirtying pages for ITER_BVEC/ITER_KVEC direct read
fs/mpage.c: forgotten WRITE_SYNC in case of data integrity write
block: kmemleak: Track the page allocations for struct request
Request queues with merging disabled will not flush the plug list after
BLK_MAX_REQUEST_COUNT requests have been queued, since the code relies
on blk_attempt_plug_merge to compute the request_count. Fix this by
computing the number of queued requests even for nomerge queues.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since they lack requests to pin the request_queue active, synchronous
bio-based drivers may have in-flight integrity work from
bio_integrity_endio() that is not flushed by blk_freeze_queue(). Flush
that work to prevent races to free the queue and the final usage of the
blk_integrity profile.
This is temporary unless/until bio-based drivers start to generically
take a q_usage_counter reference while a bio is in-flight.
Cc: Martin K. Petersen <martin.petersen@oracle.com>
[martin: fix the CONFIG_BLK_DEV_INTEGRITY=n case]
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Allow pmem, and other synchronous/bio-based block drivers, to fallback
on a per-cpu reference count managed by the core for tracking queue
live/dead state.
The existing per-cpu reference count for the blk_mq case is promoted to
be used in all block i/o scenarios. This involves initializing it by
default, waiting for it to drop to zero at exit, and holding a live
reference over the invocation of q->make_request_fn() in
generic_make_request(). The blk_mq code continues to take its own
reference per blk_mq request and retains the ability to freeze the
queue, but the check that the queue is frozen is moved to
generic_make_request().
This fixes crash signatures like the following:
BUG: unable to handle kernel paging request at ffff880140000000
[..]
Call Trace:
[<ffffffff8145e8bf>] ? copy_user_handle_tail+0x5f/0x70
[<ffffffffa004e1e0>] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem]
[<ffffffffa004e331>] pmem_make_request+0xd1/0x200 [nd_pmem]
[<ffffffff811c3162>] ? mempool_alloc+0x72/0x1a0
[<ffffffff8141f8b6>] generic_make_request+0xd6/0x110
[<ffffffff8141f966>] submit_bio+0x76/0x170
[<ffffffff81286dff>] submit_bh_wbc+0x12f/0x160
[<ffffffff81286e62>] submit_bh+0x12/0x20
[<ffffffff813395bd>] jbd2_write_superblock+0x8d/0x170
[<ffffffff8133974d>] jbd2_mark_journal_empty+0x5d/0x90
[<ffffffff813399cb>] jbd2_journal_destroy+0x24b/0x270
[<ffffffff810bc4ca>] ? put_pwq_unlocked+0x2a/0x30
[<ffffffff810bc6f5>] ? destroy_workqueue+0x225/0x250
[<ffffffff81303494>] ext4_put_super+0x64/0x360
[<ffffffff8124ab1a>] generic_shutdown_super+0x6a/0xf0
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
bdi's are initialized in two steps, bdi_init() and bdi_register(), but
destroyed in a single step by bdi_destroy() which, for a bdi embedded
in a request_queue, is called during blk_cleanup_queue() which makes
the queue invisible and starts the draining of remaining usages.
A request_queue's user can access the congestion state of the embedded
bdi as long as it holds a reference to the queue. As such, it may
access the congested state of a queue which finished
blk_cleanup_queue() but hasn't reached blk_release_queue() yet.
Because the congested state was embedded in backing_dev_info which in
turn is embedded in request_queue, accessing the congested state after
bdi_destroy() was called was fine. The bdi was destroyed but the
memory region for the congested state remained accessible till the
queue got released.
a13f35e871 ("writeback: don't embed root bdi_writeback_congested in
bdi_writeback") changed the situation. Now, the root congested state
which is expected to be pinned while request_queue remains accessible
is separately reference counted and the base ref is put during
bdi_destroy(). This means that the root congested state may go away
prematurely while the queue is between bdi_dstroy() and
blk_cleanup_queue(), which was detected by Andrey's KASAN tests.
The root cause of this problem is that bdi doesn't distinguish the two
steps of destruction, unregistration and release, and now the root
congested state actually requires a separate release step. To fix the
issue, this patch separates out bdi_unregister() and bdi_exit() from
bdi_destroy(). bdi_unregister() is called from blk_cleanup_queue()
and bdi_exit() from blk_release_queue(). bdi_destroy() is now just a
simple wrapper calling the two steps back-to-back.
While at it, the prototype of bdi_destroy() is moved right below
bdi_setup_and_register() so that the counterpart operations are
located together.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: a13f35e871 ("writeback: don't embed root bdi_writeback_congested in bdi_writeback")
Cc: stable@vger.kernel.org # v4.2+
Reported-and-tested-by: Andrey Konovalov <andreyknvl@google.com>
Link: http://lkml.kernel.org/g/CAAeHK+zUJ74Zn17=rOyxacHU18SgCfC6bsYW=6kCY5GXJBwGfQ@mail.gmail.com
Reviewed-by: Jan Kara <jack@suse.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull blk-cg updates from Jens Axboe:
"A bit later in the cycle, but this has been in the block tree for a a
while. This is basically four patchsets from Tejun, that improve our
buffered cgroup writeback. It was dependent on the other cgroup
changes, but they went in earlier in this cycle.
Series 1 is set of 5 patches that has cgroup writeback updates:
- bdi_writeback iteration fix which could lead to some wb's being
skipped or repeated during e.g. sync under memory pressure.
- Simplification of wb work wait mechanism.
- Writeback tracepoints updated to report cgroup.
Series 2 is is a set of updates for the CFQ cgroup writeback handling:
cfq has always charged all async IOs to the root cgroup. It didn't
have much choice as writeback didn't know about cgroups and there
was no way to tell who to blame for a given writeback IO.
writeback finally grew support for cgroups and now tags each
writeback IO with the appropriate cgroup to charge it against.
This patchset updates cfq so that it follows the blkcg each bio is
tagged with. Async cfq_queues are now shared across cfq_group,
which is per-cgroup, instead of per-request_queue cfq_data. This
makes all IOs follow the weight based IO resource distribution
implemented by cfq.
- Switched from GFP_ATOMIC to GFP_NOWAIT as suggested by Jeff.
- Other misc review points addressed, acks added and rebased.
Series 3 is the blkcg policy cleanup patches:
This patchset contains assorted cleanups for blkcg_policy methods
and blk[c]g_policy_data handling.
- alloc/free added for blkg_policy_data. exit dropped.
- alloc/free added for blkcg_policy_data.
- blk-throttle's async percpu allocation is replaced with direct
allocation.
- all methods now take blk[c]g_policy_data instead of blkcg_gq or
blkcg.
And finally, series 4 is a set of patches cleaning up the blkcg stats
handling:
blkcg's stats have always been somwhat of a mess. This patchset
tries to improve the situation a bit.
- The following patches added to consolidate blkcg entry point and
blkg creation. This is in itself is an improvement and helps
colllecting common stats on bio issue.
- per-blkg stats now accounted on bio issue rather than request
completion so that bio based and request based drivers can behave
the same way. The issue was spotted by Vivek.
- cfq-iosched implements custom recursive stats and blk-throttle
implements custom per-cpu stats. This patchset make blkcg core
support both by default.
- cfq-iosched and blk-throttle keep track of the same stats
multiple times. Unify them"
* 'for-4.3/blkcg' of git://git.kernel.dk/linux-block: (45 commits)
blkcg: use CGROUP_WEIGHT_* scale for io.weight on the unified hierarchy
blkcg: s/CFQ_WEIGHT_*/CFQ_WEIGHT_LEGACY_*/
blkcg: implement interface for the unified hierarchy
blkcg: misc preparations for unified hierarchy interface
blkcg: separate out tg_conf_updated() from tg_set_conf()
blkcg: move body parsing from blkg_conf_prep() to its callers
blkcg: mark existing cftypes as legacy
blkcg: rename subsystem name from blkio to io
blkcg: refine error codes returned during blkcg configuration
blkcg: remove unnecessary NULL checks from __cfqg_set_weight_device()
blkcg: reduce stack usage of blkg_rwstat_recursive_sum()
blkcg: remove cfqg_stats->sectors
blkcg: move io_service_bytes and io_serviced stats into blkcg_gq
blkcg: make blkg_[rw]stat_recursive_sum() to be able to index into blkcg_gq
blkcg: make blkcg_[rw]stat per-cpu
blkcg: add blkg_[rw]stat->aux_cnt and replace cfq_group->dead_stats with it
blkcg: consolidate blkg creation in blkcg_bio_issue_check()
blk-throttle: improve queue bypass handling
blkcg: move root blkg lookup optimization from throtl_lookup_tg() to __blkg_lookup()
blkcg: inline [__]blkg_lookup()
...
blkg (blkcg_gq) currently is created by blkcg policies invoking
blkg_lookup_create() which ends up repeating about the same code in
different policies. Theoretically, this can avoid the overhead of
looking and/or creating blkg's if blkcg is enabled but no policy is in
use; however, the cost of blkg lookup / creation is very low
especially if only the root blkcg is in use which is highly likely if
no blkcg policy is in active use - it boils down to a single very
predictable conditional and surrounding RCU protection.
This patch consolidates blkg creation to a new function
blkcg_bio_issue_check() which is called during bio issue from
generic_make_request_checks(). blkcg_bio_issue_check() is now the
only function which tries to create missing blkg's. The subsequent
policy and request_list operations just perform blkg_lookup() and if
missing falls back to the root.
* blk_get_rl() no longer tries to create blkg. It uses blkg_lookup()
instead of blkg_lookup_create().
* blk_throtl_bio() is now called from blkcg_bio_issue_check() with rcu
read locked and blkg already looked up. Both throtl_lookup_tg() and
throtl_lookup_create_tg() are dropped.
* cfq is similarly updated. cfq_lookup_create_cfqg() is replaced with
cfq_lookup_cfqg()which uses blkg_lookup().
This consolidates blkg handling and avoids unnecessary blkg creation
retries under memory pressure. In addition, this provides a common
bio entry point into blkcg where things like common accounting can be
performed.
v2: Build fixes for !CONFIG_CFQ_GROUP_IOSCHED and
!CONFIG_BLK_DEV_THROTTLING.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The way the block layer is currently written, it goes to great lengths
to avoid having to split bios; upper layer code (such as bio_add_page())
checks what the underlying device can handle and tries to always create
bios that don't need to be split.
But this approach becomes unwieldy and eventually breaks down with
stacked devices and devices with dynamic limits, and it adds a lot of
complexity. If the block layer could split bios as needed, we could
eliminate a lot of complexity elsewhere - particularly in stacked
drivers. Code that creates bios can then create whatever size bios are
convenient, and more importantly stacked drivers don't have to deal with
both their own bio size limitations and the limitations of the
(potentially multiple) devices underneath them. In the future this will
let us delete merge_bvec_fn and a bunch of other code.
We do this by adding calls to blk_queue_split() to the various
make_request functions that need it - a few can already handle arbitrary
size bios. Note that we add the call _after_ any call to
blk_queue_bounce(); this means that blk_queue_split() and
blk_recalc_rq_segments() don't need to be concerned with bouncing
affecting segment merging.
Some make_request_fn() callbacks were simple enough to audit and verify
they don't need blk_queue_split() calls. The skipped ones are:
* nfhd_make_request (arch/m68k/emu/nfblock.c)
* axon_ram_make_request (arch/powerpc/sysdev/axonram.c)
* simdisk_make_request (arch/xtensa/platforms/iss/simdisk.c)
* brd_make_request (ramdisk - drivers/block/brd.c)
* mtip_submit_request (drivers/block/mtip32xx/mtip32xx.c)
* loop_make_request
* null_queue_bio
* bcache's make_request fns
Some others are almost certainly safe to remove now, but will be left
for future patches.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Jim Paris <jim@jtan.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md/md.c' bits)
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: skip more mq-based drivers, resolve merge conflicts, etc.]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Some places use helpers now, others don't. We only have the 'is set'
helper, add helpers for setting and clearing flags too.
It was a bit of a mess of atomic vs non-atomic access. With
BIO_UPTODATE gone, we don't have any risk of concurrent access to the
flags. So relax the restriction and don't make any of them atomic. The
flags that do have serialization issues (reffed and chained), we
already handle those separately.
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently we have two different ways to signal an I/O error on a BIO:
(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback
The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.
So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
ability to handle partial request completions -- otherwise with the
current SCSI LLDs these changes could lead to silent data corruption.
- Fix two DM version bumps that were missing from the initial 4.2 DM
pull request (enabled userspace lvm2 to know certain changes have been
made).
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJVjWetAAoJEMUj8QotnQNaEngIAMVwExw0u04jqoW9rUwLDbpr
PS2A4lh/MGtMqGGPwJp5qiwnKkgQ5/FcxRpslNQYqA6KrIlnjWJhacWl7tOrwqxn
+WBsHIUwjcpwK2RqxSS3Petb6xDd7A3LfTQVhKV9xKZpZp8Y25a+1MPmUYKsFLBH
DJ1d9bXPMdN1qjBXBU1rKkVxj6z8iNz/lv24eN0MGyWhfUUTc8lQg3eey3L0BzCc
siOuupFQXaWIkbawLZrmvPPNm1iMoABC1OPZCTB1AYZYx1rqzEGUR1nZN+qWf6Wf
rZtAPZehbRzvOaf5jC6tEfAcTF23aPEyp4LD+aAQpbuC/1IBi8a3S8z6PvR5EjA=
=QY48
-----END PGP SIGNATURE-----
Merge tag 'dm-4.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
"Apologies for not pressing this request-based DM partial completion
issue further, it was an oversight on my part. We'll have to get it
fixed up properly and revisit for a future release.
- Revert block and DM core changes the removed request-based DM's
ability to handle partial request completions -- otherwise with the
current SCSI LLDs these changes could lead to silent data
corruption.
- Fix two DM version bumps that were missing from the initial 4.2 DM
pull request (enabled userspace lvm2 to know certain changes have
been made)"
* tag 'dm-4.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm cache policy smq: fix "default" version to be 1.4.0
dm: bump the ioctl version to 4.32.0
Revert "block, dm: don't copy bios for request clones"
Revert "dm: do not allocate any mempools for blk-mq request-based DM"
This reverts commit 5f1b670d0b.
Justification for revert as reported in this dm-devel post:
https://www.redhat.com/archives/dm-devel/2015-June/msg00160.html
this change should not be pushed to mainline yet.
Firstly, Christoph has a newer version of the patch that fixes silent
data corruption problem:
https://www.redhat.com/archives/dm-devel/2015-May/msg00229.html
And the new version still depends on LLDDs to always complete requests
to the end when error happens, while block API doesn't enforce such a
requirement. If the assumption is ever broken, the inconsistency between
request and bio (e.g. rq->__sector and rq->bio) will cause silent data
corruption:
https://www.redhat.com/archives/dm-devel/2015-June/msg00022.html
Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull cgroup writeback support from Jens Axboe:
"This is the big pull request for adding cgroup writeback support.
This code has been in development for a long time, and it has been
simmering in for-next for a good chunk of this cycle too. This is one
of those problems that has been talked about for at least half a
decade, finally there's a solution and code to go with it.
Also see last weeks writeup on LWN:
http://lwn.net/Articles/648292/"
* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
writeback, blkio: add documentation for cgroup writeback support
vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
writeback: do foreign inode detection iff cgroup writeback is enabled
v9fs: fix error handling in v9fs_session_init()
bdi: fix wrong error return value in cgwb_create()
buffer: remove unusued 'ret' variable
writeback: disassociate inodes from dying bdi_writebacks
writeback: implement foreign cgroup inode bdi_writeback switching
writeback: add lockdep annotation to inode_to_wb()
writeback: use unlocked_inode_to_wb transaction in inode_congested()
writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
writeback: implement [locked_]inode_to_wb_and_lock_list()
writeback: implement foreign cgroup inode detection
writeback: make writeback_control track the inode being written back
writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
writeback: implement memcg writeback domain based throttling
writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
writeback: implement memcg wb_domain
writeback: update wb_over_bg_thresh() to use wb_domain aware operations
...
Pull core block IO update from Jens Axboe:
"Nothing really major in here, mostly a collection of smaller
optimizations and cleanups, mixed with various fixes. In more detail,
this contains:
- Addition of policy specific data to blkcg for block cgroups. From
Arianna Avanzini.
- Various cleanups around command types from Christoph.
- Cleanup of the suspend block I/O path from Christoph.
- Plugging updates from Shaohua and Jeff Moyer, for blk-mq.
- Eliminating atomic inc/dec of both remaining IO count and reference
count in a bio. From me.
- Fixes for SG gap and chunk size support for data-less (discards)
IO, so we can merge these better. From me.
- Small restructuring of blk-mq shared tag support, freeing drivers
from iterating hardware queues. From Keith Busch.
- A few cfq-iosched tweaks, from Tahsin Erdogan and me. Makes the
IOPS mode the default for non-rotational storage"
* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
cfq-iosched: move group scheduling functions under ifdef
cfq-iosched: fix the setting of IOPS mode on SSDs
blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
block, cgroup: implement policy-specific per-blkcg data
block: Make CFQ default to IOPS mode on SSDs
block: add blk_set_queue_dying() to blkdev.h
blk-mq: Shared tag enhancements
block: don't honor chunk sizes for data-less IO
block: only honor SG gap prevention for merges that contain data
block: fix returnvar.cocci warnings
block, dm: don't copy bios for request clones
block: remove management of bi_remaining when restoring original bi_end_io
block: replace trylock with mutex_lock in blkdev_reread_part()
block: export blkdev_reread_part() and __blkdev_reread_part()
suspend: simplify block I/O handling
block: collapse bio bit space
block: remove unused BIO_RW_BLOCK and BIO_EOF flags
block: remove BIO_EOPNOTSUPP
...
Now that bdi layer can handle per-blkcg bdi_writeback_congested state,
blk_{set|clear}_congested() can propagate non-root blkcg congestion
state to them.
This can be easily achieved by disabling the root_rl tests in
blk_{set|clear}_congested(). Note that we still need those tests when
!CONFIG_CGROUP_WRITEBACK as otherwise we'll end up flipping root blkcg
wb's congestion state for events happening on other blkcgs.
v2: Updated for bdi_writeback_congested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_{set|clear}_queue_congested() take @q and set or clear,
respectively, the congestion state of its bdi's root wb. Because bdi
used to be able to handle congestion state only on the root wb, the
callers of those functions tested whether the congestion is on the
root blkcg and skipped if not.
This is cumbersome and makes implementation of per cgroup
bdi_writeback congestion state propagation difficult. This patch
renames blk_{set|clear}_queue_congested() to
blk_{set|clear}_congested(), and makes them take request_list instead
of request_queue and test whether the specified request_list is the
root one before updating bdi_writeback congestion state. This makes
the tests in the callers unnecessary and simplifies them.
As there are no external users of these functions, the definitions are
moved from include/linux/blkdev.h to block/blk-core.c.
This patch doesn't introduce any noticeable behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
cgroup writeback requires support from both bdi and filesystem sides.
Add BDI_CAP_CGROUP_WRITEBACK and FS_CGROUP_WRITEBACK to indicate
support and enable BDI_CAP_CGROUP_WRITEBACK on block based bdi's by
default. Also, define CONFIG_CGROUP_WRITEBACK which is enabled if
both MEMCG and BLK_CGROUP are enabled.
inode_cgwb_enabled() which determines whether a given inode's both bdi
and fs support cgroup writeback is added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear. For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi. To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.
This patch moves bdi->state into wb.
* enum bdi_state is renamed to wb_state and the prefix of all enums is
changed from BDI_ to WB_.
* Explicit zeroing of bdi->state is removed without adding zeoring of
wb->state as the whole data structure is zeroed on init anyway.
* As there's still only one bdi_writeback per backing_dev_info, all
uses of bdi->state are mechanically replaced with bdi->wb.state
introducing no behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
cgroup aware writeback support will require exposing some of blkcg
details. In preprataion, move block/blk-cgroup.h to
include/linux/blk-cgroup.h. This patch is pure file move.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.
This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence. With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.
I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
With commit ff36ab345 ("dm: remove request-based logic from
make_request_fn wrapper") DM no longer calls blk_queue_bio() directly,
so remove its export. Doing so required a forward declaration in
blk-core.c.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Last patch makes plug work for multiple queue case. However it only
works for single disk case, because it assumes only one request in the
plug list. If a task is accessing multiple disks, eg MD/DM, the
assumption is wrong. Let blk_attempt_plug_merge() record request from
the same queue.
V2: use NULL parameter in !mq case. Fix a bug. Add comments in
blk_attempt_plug_merge to make it less (hopefully) confusion.
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Current code looks like inner plug gets flushed with a
blk_finish_plug(). Actually it's a nop. All requests/callbacks are added
to current->plug, while only outmost plug is assigned to current->plug.
So inner plug always has empty request/callback list, which makes
blk_flush_plug_list() a nop. This tries to make the code more clear.
Signed-off-by: Shaohua Li <shli@fb.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This removes the request types and hacks from the block code and into the
old IDE driver. There is a small amunt of code duplication due to this,
but it's not too bad.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Because of the peculiar way that md devices are created (automatically
when the device node is opened), a new device can be created and
registered immediately after the
blk_unregister_region(disk_devt(disk), disk->minors);
call in del_gendisk().
Therefore it is important that all visible artifacts of the previous
device are removed before this call. In particular, the 'bdi'.
Since:
commit c4db59d31e
Author: Christoph Hellwig <hch@lst.de>
fs: don't reassign dirty inodes to default_backing_dev_info
moved the
device_unregister(bdi->dev);
call from bdi_unregister() to bdi_destroy() it has been quite easy to
lose a race and have a new (e.g.) "md127" be created after the
blk_unregister_region() call and before bdi_destroy() is ultimately
called by the final 'put_disk', which must come after del_gendisk().
The new device finds that the bdi name is already registered in sysfs
and complains
> [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70()
> [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127'
We can fix this by moving the bdi_destroy() call out of
blk_release_queue() (which can happen very late when a refcount
reaches zero) and into blk_cleanup_queue() - which happens exactly when the md
device driver calls it.
Then it is only necessary for md to call blk_cleanup_queue() before
del_gendisk(). As loop.c devices are also created on demand by
opening the device node, we make the same change there.
Fixes: c4db59d31e
Reported-by: Azat Khuzhin <a3at.mail@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org (v4.0)
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
blk_init_rl() allocates a mempool using mempool_create_node() with node
local memory. This only allocates the mempool and element list locally
to the requeue queue node.
What we really want to do is allocate the request itself local to the
queue. To do this, we need our own alloc and free functions that will
allocate from request_cachep and pass the request queue node in to prefer
node local memory.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull core block IO changes from Jens Axboe:
"This contains:
- A series from Christoph that cleans up and refactors various parts
of the REQ_BLOCK_PC handling. Contributions in that series from
Dongsu Park and Kent Overstreet as well.
- CFQ:
- A bug fix for cfq for realtime IO scheduling from Jeff Moyer.
- A stable patch fixing a potential crash in CFQ in OOM
situations. From Konstantin Khlebnikov.
- blk-mq:
- Add support for tag allocation policies, from Shaohua. This is
a prep patch enabling libata (and other SCSI parts) to use the
blk-mq tagging, instead of rolling their own.
- Various little tweaks from Keith and Mike, in preparation for
DM blk-mq support.
- Minor little fixes or tweaks from me.
- A double free error fix from Tony Battersby.
- The partition 4k issue fixes from Matthew and Boaz.
- Add support for zero+unprovision for blkdev_issue_zeroout() from
Martin"
* 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits)
block: remove unused function blk_bio_map_sg
block: handle the null_mapped flag correctly in blk_rq_map_user_iov
blk-mq: fix double-free in error path
block: prevent request-to-request merging with gaps if not allowed
blk-mq: make blk_mq_run_queues() static
dm: fix multipath regression due to initializing wrong request
cfq-iosched: handle failure of cfq group allocation
block: Quiesce zeroout wrapper
block: rewrite and split __bio_copy_iov()
block: merge __bio_map_user_iov into bio_map_user_iov
block: merge __bio_map_kern into bio_map_kern
block: pass iov_iter to the BLOCK_PC mapping functions
block: add a helper to free bio bounce buffer pages
block: use blk_rq_map_user_iov to implement blk_rq_map_user
block: simplify bio_map_kern
block: mark blk-mq devices as stackable
block: keep established cmd_flags when cloning into a blk-mq request
block: add blk-mq support to blk_insert_cloned_request()
block: require blk_rq_prep_clone() be given an initialized clone request
blk-mq: add tag allocation policy
...
blk_mq_alloc_request() may establish REQ_MQ_INFLIGHT in addition to
incrementing the hctx->nr_active count. Any cmd_flags that are
established in the newly allocated clone request must be preserved in
addition to the cmd_flags that are later copied over from the original
request as part of blk_rq_prep_clone().
Otherwise, if REQ_MQ_INFLIGHT isn't set in the clone request the
hctx->nr_active count won't get decremented via blk_mq_free_request().
The only consumer of blk_rq_prep_clone() is request-based DM, which uses
blk_rq_init() prior to calling blk_rq_prep_clone() for the non-blk-mq
case. Given the cloned request's cmd_flags will be 0 it is safe to OR
them with the original request's cmd_flags for both the non-blk-mq and
blk-mq cases.
Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If the request passed to blk_insert_cloned_request() was allocated by
a blk-mq device it must be submitted using blk_mq_insert_request().
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Prepare to allow blk_rq_prep_clone() to accept clone requests that were
allocated from blk-mq request queues. As such the blk_rq_prep_clone()
caller must first initialize the clone request.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.
Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead. Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device. It also removes the need for
the mtd_inodefs filesystem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If it's dying, we can't expect new request to complete and come
in an wake up other tasks waiting for requests. So after we
have marked it as dying, wake up everybody currently waiting
for a request. Once they wake, they will retry their allocation
and fail appropriately due to the state of the queue.
Tested-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block driver core update from Jens Axboe:
"This is the pull request for the core block IO changes for 3.19. Not
a huge round this time, mostly lots of little good fixes:
- Fix a bug in sysfs blktrace interface causing a NULL pointer
dereference, when enabled/disabled through that API. From Arianna
Avanzini.
- Various updates/fixes/improvements for blk-mq:
- A set of updates from Bart, mostly fixing buts in the tag
handling.
- Cleanup/code consolidation from Christoph.
- Extend queue_rq API to be able to handle batching issues of IO
requests. NVMe will utilize this shortly. From me.
- A few tag and request handling updates from me.
- Cleanup of the preempt handling for running queues from Paolo.
- Prevent running of unmapped hardware queues from Ming Lei.
- Move the kdump memory limiting check to be in the correct
location, from Shaohua.
- Initialize all software queues at init time from Takashi. This
prevents a kobject warning when CPUs are brought online that
weren't online when a queue was registered.
- Single writeback fix for I_DIRTY clearing from Tejun. Queued with
the core IO changes, since it's just a single fix.
- Version X of the __bio_add_page() segment addition retry from
Maurizio. Hope the Xth time is the charm.
- Documentation fixup for IO scheduler merging from Jan.
- Introduce (and use) generic IO stat accounting helpers for non-rq
drivers, from Gu Zheng.
- Kill off artificial limiting of max sectors in a request from
Christoph"
* 'for-3.19/core' of git://git.kernel.dk/linux-block: (26 commits)
bio: modify __bio_add_page() to accept pages that don't start a new segment
blk-mq: Fix uninitialized kobject at CPU hotplugging
blktrace: don't let the sysfs interface remove trace from running list
blk-mq: Use all available hardware queues
blk-mq: Micro-optimize bt_get()
blk-mq: Fix a race between bt_clear_tag() and bt_get()
blk-mq: Avoid that __bt_get_word() wraps multiple times
blk-mq: Fix a use-after-free
blk-mq: prevent unmapped hw queue from being scheduled
blk-mq: re-check for available tags after running the hardware queue
blk-mq: fix hang in bt_get()
blk-mq: move the kdump check to blk_mq_alloc_tag_set
blk-mq: cleanup tag free handling
blk-mq: use 'nr_cpu_ids' as highest CPU ID count for hwq <-> cpu map
blk: introduce generic io stat accounting help function
blk-mq: handle the single queue case in blk_mq_hctx_next_cpu
genhd: check for int overflow in disk_expand_part_tbl()
blk-mq: add blk_mq_free_hctx_request()
blk-mq: export blk_mq_free_request()
blk-mq: use get_cpu/put_cpu instead of preempt_disable/preempt_enable
...
This time we have some more new material than we used to have during
the last couple of development cycles.
The most important part of it to me is the introduction of a unified
interface for accessing device properties provided by platform
firmware. It works with Device Trees and ACPI in a uniform way and
drivers using it need not worry about where the properties come
from as long as the platform firmware (either DT or ACPI) makes
them available. It covers both devices and "bare" device node
objects without struct device representation as that turns out to
be necessary in some cases. This has been in the works for quite
a few months (and development cycles) and has been approved by
all of the relevant maintainers.
On top of that, some drivers are switched over to the new interface
(at25, leds-gpio, gpio_keys_polled) and some additional changes are
made to the core GPIO subsystem to allow device drivers to manipulate
GPIOs in the "canonical" way on platforms that provide GPIO information
in their ACPI tables, but don't assign names to GPIO lines (in which
case the driver needs to do that on the basis of what it knows about
the device in question). That also has been approved by the GPIO
core maintainers and the rfkill driver is now going to use it.
Second is support for hardware P-states in the intel_pstate driver.
It uses CPUID to detect whether or not the feature is supported by
the processor in which case it will be enabled by default. However,
it can be disabled entirely from the kernel command line if necessary.
Next is support for a platform firmware interface based on ACPI
operation regions used by the PMIC (Power Management Integrated
Circuit) chips on the Intel Baytrail-T and Baytrail-T-CR platforms.
That interface is used for manipulating power resources and for
thermal management: sensor temperature reporting, trip point setting
and so on.
Also the ACPI core is now going to support the _DEP configuration
information in a limited way. Basically, _DEP it supposed to reflect
off-the-hierarchy dependencies between devices which may be very
indirect, like when AML for one device accesses locations in an
operation region handled by another device's driver (usually, the
device depended on this way is a serial bus or GPIO controller).
The support added this time is sufficient to make the ACPI battery
driver work on Asus T100A, but it is general enough to be able to
cover some other use cases in the future.
Finally, we have a new cpufreq driver for the Loongson1B processor.
In addition to the above, there are fixes and cleanups all over the
place as usual and a traditional ACPICA update to a recent upstream
release.
As far as the fixes go, the ACPI LPSS (Low-power Subsystem) driver
for Intel platforms should be able to handle power management of
the DMA engine correctly, the cpufreq-dt driver should interact
with the thermal subsystem in a better way and the ACPI backlight
driver should handle some more corner cases, among other things.
On top of the ACPICA update there are fixes for race conditions
in the ACPICA's interrupt handling code which might lead to some
random and strange looking failures on some systems.
In the cleanups department the most visible part is the series
of commits targeted at getting rid of the CONFIG_PM_RUNTIME
configuration option. That was triggered by a discussion
regarding the generic power domains code during which we realized
that trying to support certain combinations of PM config options
was painful and not really worth it, because nobody would use them
in production anyway. For this reason, we decided to make
CONFIG_PM_SLEEP select CONFIG_PM_RUNTIME and that lead to the
conclusion that the latter became redundant and CONFIG_PM could
be used instead of it. The material here makes that replacement
in a major part of the tree, but there will be at least one more
batch of that in the second part of the merge window.
Specifics:
- Support for retrieving device properties information from ACPI
_DSD device configuration objects and a unified device properties
interface for device drivers (and subsystems) on top of that.
As stated above, this works with Device Trees and ACPI and allows
device drivers to be written in a platform firmware (DT or ACPI)
agnostic way. The at25, leds-gpio and gpio_keys_polled drivers
are now going to use this new interface and the GPIO subsystem
is additionally modified to allow device drivers to assign names
to GPIO resources returned by ACPI _CRS objects (in case _DSD is
not present or does not provide the expected data). The changes
in this set are mostly from Mika Westerberg, Rafael J Wysocki,
Aaron Lu, and Darren Hart with some fixes from others (Fabio Estevam,
Geert Uytterhoeven).
- Support for Hardware Managed Performance States (HWP) as described
in Volume 3, section 14.4, of the Intel SDM in the intel_pstate
driver. CPUID is used to detect whether or not the feature is
supported by the processor. If supported, it will be enabled
automatically unless the intel_pstate=no_hwp switch is present in
the kernel command line. From Dirk Brandewie.
- New Intel Broadwell-H ID for intel_pstate (Dirk Brandewie).
- Support for firmware interface based on ACPI operation regions
used by the PMIC chips on the Intel Baytrail-T and Baytrail-T-CR
platforms for power resource control and thermal management
(Aaron Lu).
- Limited support for retrieving off-the-hierarchy dependencies
between devices from ACPI _DEP device configuration objects
and deferred probing support for the ACPI battery driver based
on the _DEP information to make that driver work on Asus T100A
(Lan Tianyu).
- New cpufreq driver for the Loongson1B processor (Kelvin Cheung).
- ACPICA update to upstream revision 20141107 which only affects
tools (Bob Moore).
- Fixes for race conditions in the ACPICA's interrupt handling
code and in the ACPI code related to system suspend and resume
(Lv Zheng and Rafael J Wysocki).
- ACPI core fix for an RCU-related issue in the ioremap() regions
management code that slowed down significantly after CPUs had
been allowed to enter idle states even if they'd had RCU callbakcs
queued and triggered some problems in certain proprietary graphics
driver (and elsewhere). The fix replaces synchronize_rcu() in
that code with synchronize_rcu_expedited() which makes the issue
go away. From Konstantin Khlebnikov.
- ACPI LPSS (Low-Power Subsystem) driver fix to handle power
management of the DMA engine included into the LPSS correctly.
The problem is that the DMA engine doesn't have ACPI PM support
of its own and it simply is turned off when the last LPSS device
having ACPI PM support goes into D3cold. To work around that,
the PM domain used by the ACPI LPSS driver is redesigned so at
least one device with ACPI PM support will be on as long as the
DMA engine is in use. From Andy Shevchenko.
- ACPI backlight driver fix to avoid using it on "Win8-compatible"
systems where it doesn't work and where it was used by default by
mistake (Aaron Lu).
- Assorted minor ACPI core fixes and cleanups from Tomasz Nowicki,
Sudeep Holla, Huang Rui, Hanjun Guo, Fabian Frederick, and
Ashwin Chaugule (mostly related to the upcoming ARM64 support).
- Intel RAPL (Running Average Power Limit) power capping driver
fixes and improvements including new processor IDs (Jacob Pan).
- Generic power domains modification to power up domains after
attaching devices to them to meet the expectations of device
drivers and bus types assuming devices to be accessible at
probe time (Ulf Hansson).
- Preliminary support for controlling device clocks from the
generic power domains core code and modifications of the
ARM/shmobile platform to use that feature (Ulf Hansson).
- Assorted minor fixes and cleanups of the generic power
domains core code (Ulf Hansson, Geert Uytterhoeven).
- Assorted minor fixes and cleanups of the device clocks control
code in the PM core (Geert Uytterhoeven, Grygorii Strashko).
- Consolidation of device power management Kconfig options by making
CONFIG_PM_SLEEP select CONFIG_PM_RUNTIME and removing the latter
which is now redundant (Rafael J Wysocki and Kevin Hilman). That
is the first batch of the changes needed for this purpose.
- Core device runtime power management support code cleanup related
to the execution of callbacks (Andrzej Hajda).
- cpuidle ARM support improvements (Lorenzo Pieralisi).
- cpuidle cleanup related to the CPUIDLE_FLAG_TIME_VALID flag and
a new MAINTAINERS entry for ARM Exynos cpuidle (Daniel Lezcano and
Bartlomiej Zolnierkiewicz).
- New cpufreq driver callback (->ready) to be executed when the
cpufreq core is ready to use a given policy object and cpufreq-dt
driver modification to use that callback for cooling device
registration (Viresh Kumar).
- cpufreq core fixes and cleanups (Viresh Kumar, Vince Hsu,
James Geboski, Tomeu Vizoso).
- Assorted fixes and cleanups in the cpufreq-pcc, intel_pstate,
cpufreq-dt, pxa2xx cpufreq drivers (Lenny Szubowicz, Ethan Zhao,
Stefan Wahren, Petr Cvek).
- OPP (Operating Performance Points) framework modification to
allow OPPs to be removed too and update of a few cpufreq drivers
(cpufreq-dt, exynos5440, imx6q, cpufreq) to remove OPPs (added
during initialization) on driver removal (Viresh Kumar).
- Hibernation core fixes and cleanups (Tina Ruchandani and
Markus Elfring).
- PM Kconfig fix related to CPU power management (Pankaj Dubey).
- cpupower tool fix (Prarit Bhargava).
/
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=5dox
-----END PGP SIGNATURE-----
Merge tag 'pm+acpi-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:
"This time we have some more new material than we used to have during
the last couple of development cycles.
The most important part of it to me is the introduction of a unified
interface for accessing device properties provided by platform
firmware. It works with Device Trees and ACPI in a uniform way and
drivers using it need not worry about where the properties come from
as long as the platform firmware (either DT or ACPI) makes them
available. It covers both devices and "bare" device node objects
without struct device representation as that turns out to be necessary
in some cases. This has been in the works for quite a few months (and
development cycles) and has been approved by all of the relevant
maintainers.
On top of that, some drivers are switched over to the new interface
(at25, leds-gpio, gpio_keys_polled) and some additional changes are
made to the core GPIO subsystem to allow device drivers to manipulate
GPIOs in the "canonical" way on platforms that provide GPIO
information in their ACPI tables, but don't assign names to GPIO lines
(in which case the driver needs to do that on the basis of what it
knows about the device in question). That also has been approved by
the GPIO core maintainers and the rfkill driver is now going to use
it.
Second is support for hardware P-states in the intel_pstate driver.
It uses CPUID to detect whether or not the feature is supported by the
processor in which case it will be enabled by default. However, it
can be disabled entirely from the kernel command line if necessary.
Next is support for a platform firmware interface based on ACPI
operation regions used by the PMIC (Power Management Integrated
Circuit) chips on the Intel Baytrail-T and Baytrail-T-CR platforms.
That interface is used for manipulating power resources and for
thermal management: sensor temperature reporting, trip point setting
and so on.
Also the ACPI core is now going to support the _DEP configuration
information in a limited way. Basically, _DEP it supposed to reflect
off-the-hierarchy dependencies between devices which may be very
indirect, like when AML for one device accesses locations in an
operation region handled by another device's driver (usually, the
device depended on this way is a serial bus or GPIO controller). The
support added this time is sufficient to make the ACPI battery driver
work on Asus T100A, but it is general enough to be able to cover some
other use cases in the future.
Finally, we have a new cpufreq driver for the Loongson1B processor.
In addition to the above, there are fixes and cleanups all over the
place as usual and a traditional ACPICA update to a recent upstream
release.
As far as the fixes go, the ACPI LPSS (Low-power Subsystem) driver for
Intel platforms should be able to handle power management of the DMA
engine correctly, the cpufreq-dt driver should interact with the
thermal subsystem in a better way and the ACPI backlight driver should
handle some more corner cases, among other things.
On top of the ACPICA update there are fixes for race conditions in the
ACPICA's interrupt handling code which might lead to some random and
strange looking failures on some systems.
In the cleanups department the most visible part is the series of
commits targeted at getting rid of the CONFIG_PM_RUNTIME configuration
option. That was triggered by a discussion regarding the generic
power domains code during which we realized that trying to support
certain combinations of PM config options was painful and not really
worth it, because nobody would use them in production anyway. For
this reason, we decided to make CONFIG_PM_SLEEP select
CONFIG_PM_RUNTIME and that lead to the conclusion that the latter
became redundant and CONFIG_PM could be used instead of it. The
material here makes that replacement in a major part of the tree, but
there will be at least one more batch of that in the second part of
the merge window.
Specifics:
- Support for retrieving device properties information from ACPI _DSD
device configuration objects and a unified device properties
interface for device drivers (and subsystems) on top of that. As
stated above, this works with Device Trees and ACPI and allows
device drivers to be written in a platform firmware (DT or ACPI)
agnostic way. The at25, leds-gpio and gpio_keys_polled drivers are
now going to use this new interface and the GPIO subsystem is
additionally modified to allow device drivers to assign names to
GPIO resources returned by ACPI _CRS objects (in case _DSD is not
present or does not provide the expected data). The changes in
this set are mostly from Mika Westerberg, Rafael J Wysocki, Aaron
Lu, and Darren Hart with some fixes from others (Fabio Estevam,
Geert Uytterhoeven).
- Support for Hardware Managed Performance States (HWP) as described
in Volume 3, section 14.4, of the Intel SDM in the intel_pstate
driver. CPUID is used to detect whether or not the feature is
supported by the processor. If supported, it will be enabled
automatically unless the intel_pstate=no_hwp switch is present in
the kernel command line. From Dirk Brandewie.
- New Intel Broadwell-H ID for intel_pstate (Dirk Brandewie).
- Support for firmware interface based on ACPI operation regions used
by the PMIC chips on the Intel Baytrail-T and Baytrail-T-CR
platforms for power resource control and thermal management (Aaron
Lu).
- Limited support for retrieving off-the-hierarchy dependencies
between devices from ACPI _DEP device configuration objects and
deferred probing support for the ACPI battery driver based on the
_DEP information to make that driver work on Asus T100A (Lan
Tianyu).
- New cpufreq driver for the Loongson1B processor (Kelvin Cheung).
- ACPICA update to upstream revision 20141107 which only affects
tools (Bob Moore).
- Fixes for race conditions in the ACPICA's interrupt handling code
and in the ACPI code related to system suspend and resume (Lv Zheng
and Rafael J Wysocki).
- ACPI core fix for an RCU-related issue in the ioremap() regions
management code that slowed down significantly after CPUs had been
allowed to enter idle states even if they'd had RCU callbakcs
queued and triggered some problems in certain proprietary graphics
driver (and elsewhere). The fix replaces synchronize_rcu() in that
code with synchronize_rcu_expedited() which makes the issue go
away. From Konstantin Khlebnikov.
- ACPI LPSS (Low-Power Subsystem) driver fix to handle power
management of the DMA engine included into the LPSS correctly. The
problem is that the DMA engine doesn't have ACPI PM support of its
own and it simply is turned off when the last LPSS device having
ACPI PM support goes into D3cold. To work around that, the PM
domain used by the ACPI LPSS driver is redesigned so at least one
device with ACPI PM support will be on as long as the DMA engine is
in use. From Andy Shevchenko.
- ACPI backlight driver fix to avoid using it on "Win8-compatible"
systems where it doesn't work and where it was used by default by
mistake (Aaron Lu).
- Assorted minor ACPI core fixes and cleanups from Tomasz Nowicki,
Sudeep Holla, Huang Rui, Hanjun Guo, Fabian Frederick, and Ashwin
Chaugule (mostly related to the upcoming ARM64 support).
- Intel RAPL (Running Average Power Limit) power capping driver fixes
and improvements including new processor IDs (Jacob Pan).
- Generic power domains modification to power up domains after
attaching devices to them to meet the expectations of device
drivers and bus types assuming devices to be accessible at probe
time (Ulf Hansson).
- Preliminary support for controlling device clocks from the generic
power domains core code and modifications of the ARM/shmobile
platform to use that feature (Ulf Hansson).
- Assorted minor fixes and cleanups of the generic power domains core
code (Ulf Hansson, Geert Uytterhoeven).
- Assorted minor fixes and cleanups of the device clocks control code
in the PM core (Geert Uytterhoeven, Grygorii Strashko).
- Consolidation of device power management Kconfig options by making
CONFIG_PM_SLEEP select CONFIG_PM_RUNTIME and removing the latter
which is now redundant (Rafael J Wysocki and Kevin Hilman). That
is the first batch of the changes needed for this purpose.
- Core device runtime power management support code cleanup related
to the execution of callbacks (Andrzej Hajda).
- cpuidle ARM support improvements (Lorenzo Pieralisi).
- cpuidle cleanup related to the CPUIDLE_FLAG_TIME_VALID flag and a
new MAINTAINERS entry for ARM Exynos cpuidle (Daniel Lezcano and
Bartlomiej Zolnierkiewicz).
- New cpufreq driver callback (->ready) to be executed when the
cpufreq core is ready to use a given policy object and cpufreq-dt
driver modification to use that callback for cooling device
registration (Viresh Kumar).
- cpufreq core fixes and cleanups (Viresh Kumar, Vince Hsu, James
Geboski, Tomeu Vizoso).
- Assorted fixes and cleanups in the cpufreq-pcc, intel_pstate,
cpufreq-dt, pxa2xx cpufreq drivers (Lenny Szubowicz, Ethan Zhao,
Stefan Wahren, Petr Cvek).
- OPP (Operating Performance Points) framework modification to allow
OPPs to be removed too and update of a few cpufreq drivers
(cpufreq-dt, exynos5440, imx6q, cpufreq) to remove OPPs (added
during initialization) on driver removal (Viresh Kumar).
- Hibernation core fixes and cleanups (Tina Ruchandani and Markus
Elfring).
- PM Kconfig fix related to CPU power management (Pankaj Dubey).
- cpupower tool fix (Prarit Bhargava)"
* tag 'pm+acpi-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (120 commits)
i2c-omap / PM: Drop CONFIG_PM_RUNTIME from i2c-omap.c
dmaengine / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
tools: cpupower: fix return checks for sysfs_get_idlestate_count()
drivers: sh / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
e1000e / igb / PM: Eliminate CONFIG_PM_RUNTIME
MMC / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
MFD / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
misc / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
media / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
input / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
leds: leds-gpio: Fix multiple instances registration without 'label' property
iio / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
hsi / OMAP / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
i2c-hid / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
drm / exynos / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
gpio / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
hwrandom / exynos / PM: Use CONFIG_PM in #ifdef
block / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM
USB / PM: Drop CONFIG_PM_RUNTIME from the USB core
PM: Merge the SET*_RUNTIME_PM_OPS() macros
...
blk-mq users are allowed to free the memory request_queue.tag_set
points at after blk_cleanup_queue() has finished but before
blk_release_queue() has started. This can happen e.g. in the SCSI
core. The SCSI core namely embeds the tag_set structure in a SCSI
host structure. The SCSI host structure is freed by
scsi_host_dev_release(). This function is called after
blk_cleanup_queue() finished but can be called before
blk_release_queue().
This means that it is not safe to access request_queue.tag_set from
inside blk_release_queue(). Hence remove the blk_sync_queue() call
from blk_release_queue(). This call is not necessary - outstanding
requests must have finished before blk_release_queue() is
called. Additionally, move the blk_mq_free_queue() call from
blk_release_queue() to blk_cleanup_queue() to avoid that struct
request_queue.tag_set gets accessed after it has been freed.
This patch avoids that the following kernel oops can be triggered
when deleting a SCSI host for which scsi-mq was enabled:
Call Trace:
[<ffffffff8109a7c4>] lock_acquire+0xc4/0x270
[<ffffffff814ce111>] mutex_lock_nested+0x61/0x380
[<ffffffff812575f0>] blk_mq_free_queue+0x30/0x180
[<ffffffff8124d654>] blk_release_queue+0x84/0xd0
[<ffffffff8126c29b>] kobject_cleanup+0x7b/0x1a0
[<ffffffff8126c140>] kobject_put+0x30/0x70
[<ffffffff81245895>] blk_put_queue+0x15/0x20
[<ffffffff8125c409>] disk_release+0x99/0xd0
[<ffffffff8133d056>] device_release+0x36/0xb0
[<ffffffff8126c29b>] kobject_cleanup+0x7b/0x1a0
[<ffffffff8126c140>] kobject_put+0x30/0x70
[<ffffffff8125a78a>] put_disk+0x1a/0x20
[<ffffffff811d4cb5>] __blkdev_put+0x135/0x1b0
[<ffffffff811d56a0>] blkdev_put+0x50/0x160
[<ffffffff81199eb4>] kill_block_super+0x44/0x70
[<ffffffff8119a2a4>] deactivate_locked_super+0x44/0x60
[<ffffffff8119a87e>] deactivate_super+0x4e/0x70
[<ffffffff811b9833>] cleanup_mnt+0x43/0x90
[<ffffffff811b98d2>] __cleanup_mnt+0x12/0x20
[<ffffffff8107252c>] task_work_run+0xac/0xe0
[<ffffffff81002c01>] do_notify_resume+0x61/0xa0
[<ffffffff814d2c58>] int_signal+0x12/0x17
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robert Elliott <elliott@hp.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Alexander Gordeev <agordeev@redhat.com>
Cc: <stable@vger.kernel.org> # v3.13+
Signed-off-by: Jens Axboe <axboe@fb.com>
After commit b2b49ccbdd (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is
selected) PM_RUNTIME is always set if PM is set, so #ifdef blocks
depending on CONFIG_PM_RUNTIME may now be changed to depend on
CONFIG_PM.
Replace CONFIG_PM_RUNTIME with CONFIG_PM in the block device core.
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
