Some request_fn implementations, e.g. scsi_request_fn(), unlock
the queue lock internally. This may result in multiple threads
executing request_fn for the same queue simultaneously. Keep
track of the number of active request_fn calls and make sure that
blk_cleanup_queue() waits until all active request_fn invocations
have finished. A block driver may start cleaning up resources
needed by its request_fn as soon as blk_cleanup_queue() finished,
so blk_cleanup_queue() must wait for all outstanding request_fn
invocations to finish.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reported-by: Chanho Min <chanho.min@lge.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A block driver may start cleaning up resources needed by its
request_fn as soon as blk_cleanup_queue() finished, so request_fn
must not be invoked after draining finished. This is important
when blk_run_queue() is invoked without any requests in progress.
As an example, if blk_drain_queue() and scsi_run_queue() run in
parallel, blk_drain_queue() may have finished all requests after
scsi_run_queue() has taken a SCSI device off the starved list but
before that last function has had a chance to run the queue.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Chanho Min <chanho.min@lge.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
QUEUE_FLAG_DEAD is used to indicate that queuing new requests must
stop. After this flag has been set queue draining starts. However,
during the queue draining phase it is still safe to invoke the
queue's request_fn, so QUEUE_FLAG_DYING is a better name for this
flag.
This patch has been generated by running the following command
over the kernel source tree:
git grep -lEw 'blk_queue_dead|QUEUE_FLAG_DEAD' |
xargs sed -i.tmp -e 's/blk_queue_dead/blk_queue_dying/g' \
-e 's/QUEUE_FLAG_DEAD/QUEUE_FLAG_DYING/g'; \
sed -i.tmp -e "s/QUEUE_FLAG_DYING$(printf \\t)*5/QUEUE_FLAG_DYING$(printf \\t)5/g" \
include/linux/blkdev.h; \
sed -i.tmp -e 's/ DEAD/ DYING/g' -e 's/dead queue/a dying queue/' \
-e 's/Dead queue/A dying queue/' block/blk-core.c
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Chanho Min <chanho.min@lge.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.
This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
- blk_check_merge_flags() verifies that cmd_flags / bi_rw are
compatible. This function is called for both req-req and req-bio
merging.
- blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used
to query the maximum sector count for a given request or queue. The
calls will return the right value from the queue limits given the
type of command (RW, discard, write same, etc.)
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove special-casing of non-rw fs style requests (discard). The nomerge
flags are consolidated in blk_types.h, and rq_mergeable() and
bio_mergeable() have been modified to use them.
bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. write same).
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The SCSI discard request merge never worked, and looks no solution
for in future, let's disable it temporarily.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper to map a bio to a scatterlist, modelled after
blk_rq_map_sg.
This helper is useful for any driver that wants to create
a scatterlist from its ->make_request_fn method.
Changes in v2:
- Use __blk_segment_map_sg to avoid duplicated code
- Add cocbook style function comment
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a disk has large discard_granularity and small max_discard_sectors,
discards are not split with optimal alignment. In the limit case of
discard_granularity == max_discard_sectors, no request could be aligned
correctly, so in fact you might end up with no discarded logical blocks
at all.
Another example that helps showing the condition in the patch is with
discard_granularity == 64, max_discard_sectors == 128. A request that is
submitted for 256 sectors 2..257 will be split in two: 2..129, 130..257.
However, only 2 aligned blocks out of 3 are included in the request;
128..191 may be left intact and not discarded. With this patch, the
first request will be truncated to ensure good alignment of what's left,
and the split will be 2..127, 128..255, 256..257. The patch will also
take into account the discard_alignment.
At most one extra request will be introduced, because the first request
will be reduced by at most granularity-1 sectors, and granularity
must be less than max_discard_sectors. Subsequent requests will run
on round_down(max_discard_sectors, granularity) sectors, as in the
current code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This will allow md/raid to know why the unplug was called,
and will be able to act according - if !from_schedule it
is safe to perform tasks which could themselves schedule.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Both md and umem has similar code for getting notified on an
blk_finish_plug event.
Centralize this code in block/ and allow each driver to
provide its distinctive difference.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, request_queue has one request_list to allocate requests
from regardless of blkcg of the IO being issued. When the unified
request pool is used up, cfq proportional IO limits become meaningless
- whoever grabs the next request being freed wins the race regardless
of the configured weights.
This can be easily demonstrated by creating a blkio cgroup w/ very low
weight, put a program which can issue a lot of random direct IOs there
and running a sequential IO from a different cgroup. As soon as the
request pool is used up, the sequential IO bandwidth crashes.
This patch implements per-blkg request_list. Each blkg has its own
request_list and any IO allocates its request from the matching blkg
making blkcgs completely isolated in terms of request allocation.
* Root blkcg uses the request_list embedded in each request_queue,
which was renamed to @q->root_rl from @q->rq. While making blkcg rl
handling a bit harier, this enables avoiding most overhead for root
blkcg.
* Queue fullness is properly per request_list but bdi isn't blkcg
aware yet, so congestion state currently just follows the root
blkcg. As writeback isn't aware of blkcg yet, this works okay for
async congestion but readahead may get the wrong signals. It's
better than blkcg completely collapsing with shared request_list but
needs to be improved with future changes.
* After this change, each block cgroup gets a full request pool making
resource consumption of each cgroup higher. This makes allowing
non-root users to create cgroups less desirable; however, note that
allowing non-root users to directly manage cgroups is already
severely broken regardless of this patch - each block cgroup
consumes kernel memory and skews IO weight (IO weights are not
hierarchical).
v2: queue-sysfs.txt updated and patch description udpated as suggested
by Vivek.
v3: blk_get_rl() wasn't checking error return from
blkg_lookup_create() and may cause oops on lookup failure. Fix it
by falling back to root_rl on blkg lookup failures. This problem
was spotted by Rakesh Iyer <rni@google.com>.
v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in
request waitqueue". blk_drain_queue() now wakes up waiters on all
blkg->rl on the target queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Request allocation is about to be made per-blkg meaning that there'll
be multiple request lists.
* Make queue full state per request_list. blk_*queue_full() functions
are renamed to blk_*rl_full() and takes @rl instead of @q.
* Rename blk_init_free_list() to blk_init_rl() and make it take @rl
instead of @q. Also add @gfp_mask parameter.
* Add blk_exit_rl() instead of destroying rl directly from
blk_release_queue().
* Add request_list->q and make request alloc/free functions -
blk_free_request(), [__]freed_request(), __get_request() - take @rl
instead of @q.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add q->nr_rqs[] which currently behaves the same as q->rq.count[] and
move q->rq.elvpriv to q->nr_rqs_elvpriv. blk_drain_queue() is updated
to use q->nr_rqs[] instead of q->rq.count[].
These counters separates queue-wide request statistics from the
request list and allow implementation of per-queue request allocation.
While at it, properly indent fields of struct request_list.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This function was only used by btrfs code in btrfs_abort_devices()
(seems in a wrong way).
It was removed in commit d07eb91170,
So, Let's remove the dead code to avoid any confusion.
Changes in v2: update commit log, btrfs_abort_devices() was removed
already.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org
Cc: Chris Mason <chris.mason@oracle.com>
Cc: linux-btrfs@vger.kernel.org
Cc: David Sterba <dave@jikos.cz>
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge block/IO core bits from Jens Axboe:
"This is a bit bigger on the core side than usual, but that is purely
because we decided to hold off on parts of Tejun's submission on 3.4
to give it a bit more time to simmer. As a consequence, it's seen a
long cycle in for-next.
It contains:
- Bug fix from Dan, wrong locking type.
- Relax splice gifting restriction from Eric.
- A ton of updates from Tejun, primarily for blkcg. This improves
the code a lot, making the API nicer and cleaner, and also includes
fixes for how we handle and tie policies and re-activate on
switches. The changes also include generic bug fixes.
- A simple fix from Vivek, along with a fix for doing proper delayed
allocation of the blkcg stats."
Fix up annoying conflict just due to different merge resolution in
Documentation/feature-removal-schedule.txt
* 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits)
blkcg: tg_stats_alloc_lock is an irq lock
vmsplice: relax alignement requirements for SPLICE_F_GIFT
blkcg: use radix tree to index blkgs from blkcg
blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
block: fix elvpriv allocation failure handling
block: collapse blk_alloc_request() into get_request()
blkcg: collapse blkcg_policy_ops into blkcg_policy
blkcg: embed struct blkg_policy_data in policy specific data
blkcg: mass rename of blkcg API
blkcg: style cleanups for blk-cgroup.h
blkcg: remove blkio_group->path[]
blkcg: blkg_rwstat_read() was missing inline
blkcg: shoot down blkgs if all policies are deactivated
blkcg: drop stuff unused after per-queue policy activation update
blkcg: implement per-queue policy activation
blkcg: add request_queue->root_blkg
blkcg: make request_queue bypassing on allocation
blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
blkcg: make blkg_conf_prep() take @pol and return with queue lock held
blkcg: remove static policy ID enums
...
I see builds failing with:
CC [M] drivers/mmc/host/dw_mmc.o
In file included from drivers/mmc/host/dw_mmc.c:15:
include/linux/blkdev.h:1404: warning: 'struct task_struct' declared inside parameter list
include/linux/blkdev.h:1404: warning: its scope is only this definition or declaration, which is probably not what you want
include/linux/blkdev.h:1408: warning: 'struct task_struct' declared inside parameter list
include/linux/blkdev.h:1413: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'blk_needs_flush_plug'
make[4]: *** [drivers/mmc/host/dw_mmc.o] Error 1
This is because dw_mmc.c includes linux/blkdev.h as the very first file,
and when CONFIG_BLOCK=n, blkdev.h omits all includes.
As it requires linux/sched.h even when CONFIG_BLOCK=n, move this out of
the #ifdef.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'v3.4-rc5' into for-3.5/core
The core branch is behind driver commits that we want to build
on for 3.5, hence I'm pulling in a later -rc.
Linux 3.4-rc5
Conflicts:
Documentation/feature-removal-schedule.txt
Signed-off-by: Jens Axboe <axboe@kernel.dk>
During the recent blkcg cleanup, most of blkcg API has changed to such
extent that mass renaming wouldn't cause any noticeable pain. Take
the chance and cleanup the naming.
* Rename blkio_cgroup to blkcg.
* Drop blkio / blkiocg prefixes and consistently use blkcg.
* Rename blkio_group to blkcg_gq, which is consistent with io_cq but
keep the blkg prefix / variable name.
* Rename policy method type and field names to signify they're dealing
with policy data.
* Rename blkio_policy_type to blkcg_policy.
This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All blkcg policies were assumed to be enabled on all request_queues.
Due to various implementation obstacles, during the recent blkcg core
updates, this was temporarily implemented as shooting down all !root
blkgs on elevator switch and policy [de]registration combined with
half-broken in-place root blkg updates. In addition to being buggy
and racy, this meant losing all blkcg configurations across those
events.
Now that blkcg is cleaned up enough, this patch replaces the temporary
implementation with proper per-queue policy activation. Each blkcg
policy should call the new blkcg_[de]activate_policy() to enable and
disable the policy on a specific queue. blkcg_activate_policy()
allocates and installs policy data for the policy for all existing
blkgs. blkcg_deactivate_policy() does the reverse. If a policy is
not enabled for a given queue, blkg printing / config functions skip
the respective blkg for the queue.
blkcg_activate_policy() also takes care of root blkg creation, and
cfq_init_queue() and blk_throtl_init() are updated accordingly.
This replaces blkcg_bypass_{start|end}() and update_root_blkg_pd()
unnecessary. Dropped.
v2: cfq_init_queue() was returning uninitialized @ret on root_group
alloc failure if !CONFIG_CFQ_GROUP_IOSCHED. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With per-queue policy activation, root blkg creation will be moved to
blkcg core. Add q->root_blkg in preparation. For blk-throtl, this
replaces throtl_data->root_tg; however, cfq needs to keep
cfqd->root_group for !CONFIG_CFQ_GROUP_IOSCHED.
This is to prepare for per-queue policy activation and doesn't cause
any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove BLKIO_POLICY_* enums and let blkio_policy_register() allocate
@pol->plid dynamically on registration. The maximum number of blkcg
policies which can be registered at the same time is defined by
BLKCG_MAX_POLS constant added to include/linux/blkdev.h.
Note that blkio_policy_register() now may fail. Policy init functions
updated accordingly and unnecessary ifdefs removed from cfq_init().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that blkg additions / removals are always done under both q and
blkcg locks, the only places RCU locking is necessary are
blkg_lookup[_create]() for lookup w/o blkcg lock. This patch drops
unncessary RCU locking replacing it with plain blkcg locking as
necessary.
* blkiocg_pre_destroy() already perform proper locking and don't need
RCU. Dropped.
* blkio_read_blkg_stats() now uses blkcg->lock instead of RCU read
lock. This isn't a hot path.
* Now unnecessary synchronize_rcu() from queue exit paths removed.
This makes q->nr_blkgs unnecessary. Dropped.
* RCU annotation on blkg->q removed.
-v2: Vivek pointed out that blkg_lookup_create() still needs to be
called under rcu_read_lock(). Updated.
-v3: After the update, stats_lock locking in blkio_read_blkg_stats()
shouldn't be using _irq variant as it otherwise ends up enabling
irq while blkcg->lock is locked. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the previous patch to move blkg list heads and counters to
request_queue and blkg, logic to manage them in both policies are
almost identical and can be moved to blkcg core.
This patch moves blkg link logic into blkg_lookup_create(), implements
common blkg unlink code in blkg_destroy(), and updates
blkg_destory_all() so that it's policy specific and can skip root
group. The updated blkg_destroy_all() is now used to both clear queue
for bypassing and elv switching, and release all blkgs on q exit.
This patch introduces a race window where policy [de]registration may
race against queue blkg clearing. This can only be a problem on cfq
unload and shouldn't be a real problem in practice (and we have many
other places where this race already exists). Future patches will
remove these unlikely races.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, specific policy implementations are responsible for
maintaining list and number of blkgs. This duplicates code
unnecessarily, and hinders factoring common code and providing blkcg
API with better defined semantics.
After this patch, request_queue hosts list heads and counters and blkg
has list nodes for both policies. This patch only relocates the
necessary fields and the next patch will actually move management code
into blkcg core.
Note that request_queue->blkg_list[] and ->nr_blkgs[] are hardcoded to
have 2 elements. This is to avoid include dependency and will be
removed by the next patch.
This patch doesn't introduce any behavior change.
-v2: Now unnecessary conditional on CONFIG_BLK_CGROUP_MODULE removed
as pointed out by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Keep track of all request_queues which have blkcg initialized and turn
on bypass and invoke blkcg_clear_queue() on all before making changes
to blkcg policies.
This is to prepare for moving blkg management into blkcg core. Note
that this uses more brute force than necessary. Finer grained shoot
down will be implemented later and given that policy [un]registration
almost never happens on running systems (blk-throtl can't be built as
a module and cfq usually is the builtin default iosched), this
shouldn't be a problem for the time being.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rename and extend elv_queisce_start/end() to
blk_queue_bypass_start/end() which are exported and supports nesting
via @q->bypass_depth. Also add blk_queue_bypass() to test bypass
state.
This will be further extended and used for blkio_group management.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
put_io_context() performed a complex trylock dancing to avoid
deferring ioc release to workqueue. It was also broken on UP because
trylock was always assumed to succeed which resulted in unbalanced
preemption count.
While there are ways to fix the UP breakage, even the most
pathological microbench (forced ioc allocation and tight fork/exit
loop) fails to show any appreciable performance benefit of the
optimization. Strip it out. If there turns out to be workloads which
are affected by this change, simpler optimization from the discussion
thread can be applied later.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1328514611.21268.66.camel@sli10-conroe>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* 'for-3.3/core' of git://git.kernel.dk/linux-block: (37 commits)
Revert "block: recursive merge requests"
block: Stop using macro stubs for the bio data integrity calls
blockdev: convert some macros to static inlines
fs: remove unneeded plug in mpage_readpages()
block: Add BLKROTATIONAL ioctl
block: Introduce blk_set_stacking_limits function
block: remove WARN_ON_ONCE() in exit_io_context()
block: an exiting task should be allowed to create io_context
block: ioc_cgroup_changed() needs to be exported
block: recursive merge requests
block, cfq: fix empty queue crash caused by request merge
block, cfq: move icq creation and rq->elv.icq association to block core
block, cfq: restructure io_cq creation path for io_context interface cleanup
block, cfq: move io_cq exit/release to blk-ioc.c
block, cfq: move icq cache management to block core
block, cfq: move io_cq lookup to blk-ioc.c
block, cfq: move cfqd->icq_list to request_queue and add request->elv.icq
block, cfq: reorganize cfq_io_context into generic and cfq specific parts
block: remove elevator_queue->ops
block: reorder elevator switch sequence
...
Fix up conflicts in:
- block/blk-cgroup.c
Switch from can_attach_task to can_attach
- block/cfq-iosched.c
conflict with now removed cic index changes (we now use q->id instead)
Linux allows executing the SG_IO ioctl on a partition or LVM volume, and
will pass the command to the underlying block device. This is
well-known, but it is also a large security problem when (via Unix
permissions, ACLs, SELinux or a combination thereof) a program or user
needs to be granted access only to part of the disk.
This patch lets partitions forward a small set of harmless ioctls;
others are logged with printk so that we can see which ioctls are
actually sent. In my tests only CDROM_GET_CAPABILITY actually occurred.
Of course it was being sent to a (partition on a) hard disk, so it would
have failed with ENOTTY and the patch isn't changing anything in
practice. Still, I'm treating it specially to avoid spamming the logs.
In principle, this restriction should include programs running with
CAP_SYS_RAWIO. If for example I let a program access /dev/sda2 and
/dev/sdb, it still should not be able to read/write outside the
boundaries of /dev/sda2 independent of the capabilities. However, for
now programs with CAP_SYS_RAWIO will still be allowed to send the
ioctls. Their actions will still be logged.
This patch does not affect the non-libata IDE driver. That driver
however already tests for bd != bd->bd_contains before issuing some
ioctl; it could be restricted further to forbid these ioctls even for
programs running with CAP_SYS_ADMIN/CAP_SYS_RAWIO.
Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[ Make it also print the command name when warning - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a wrapper around scsi_cmd_ioctl that takes a block device.
The function will then be enhanced to detect partition block devices
and, in that case, subject the ioctls to whitelisting.
Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We prefer to program in C rather than preprocessor and it fixes this
warning when CONFIG_BLK_DEV_INTEGRITY is not set:
drivers/md/dm-table.c: In function 'dm_table_set_integrity':
drivers/md/dm-table.c:1285:3: warning: statement with no effect [-Wunused-value]
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stacking driver queue limits are typically bounded exclusively by the
capabilities of the low level devices, not by the stacking driver
itself.
This patch introduces blk_set_stacking_limits() which has more liberal
metrics than the default queue limits function. This allows us to
inherit topology parameters from bottom devices without manually
tweaking the default limits in each driver prior to calling the stacking
function.
Since there is now a clear distinction between stacking and low-level
devices, blk_set_default_limits() has been modified to carry the more
conservative values that we used to manually set in
blk_queue_make_request().
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Most of icq management is about to be moved out of cfq into blk-ioc.
This patch prepares for it.
* Move cfqd->icq_list to request_queue->icq_list
* Make request explicitly point to icq instead of through elevator
private data. ->elevator_private[3] is replaced with sub struct elv
which contains icq pointer and priv[2]. cfq is updated accordingly.
* Meaningless clearing of ->elevator_private[0] removed from
elv_set_request(). At that point in code, the field was guaranteed
to be %NULL anyway.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
cic is association between io_context and request_queue. A cic is
linked from both ioc and q and should be destroyed when either one
goes away. As ioc and q both have their own locks, locking becomes a
bit complex - both orders work for removal from one but not from the
other.
Currently, cfq tries to circumvent this locking order issue with RCU.
ioc->lock nests inside queue_lock but the radix tree and cic's are
also protected by RCU allowing either side to walk their lists without
grabbing lock.
This rather unconventional use of RCU quickly devolves into extremely
fragile convolution. e.g. The following is from cfqd going away too
soon after ioc and q exits raced.
general protection fault: 0000 [#1] PREEMPT SMP
CPU 2
Modules linked in:
[ 88.503444]
Pid: 599, comm: hexdump Not tainted 3.1.0-rc10-work+ #158 Bochs Bochs
RIP: 0010:[<ffffffff81397628>] [<ffffffff81397628>] cfq_exit_single_io_context+0x58/0xf0
...
Call Trace:
[<ffffffff81395a4a>] call_for_each_cic+0x5a/0x90
[<ffffffff81395ab5>] cfq_exit_io_context+0x15/0x20
[<ffffffff81389130>] exit_io_context+0x100/0x140
[<ffffffff81098a29>] do_exit+0x579/0x850
[<ffffffff81098d5b>] do_group_exit+0x5b/0xd0
[<ffffffff81098de7>] sys_exit_group+0x17/0x20
[<ffffffff81b02f2b>] system_call_fastpath+0x16/0x1b
The only real hot path here is cic lookup during request
initialization and avoiding extra locking requires very confined use
of RCU. This patch makes cic removal from both ioc and request_queue
perform double-locking and unlink immediately.
* From q side, the change is almost trivial as ioc->lock nests inside
queue_lock. It just needs to grab each ioc->lock as it walks
cic_list and unlink it.
* From ioc side, it's a bit more difficult because of inversed lock
order. ioc needs its lock to walk its cic_list but can't grab the
matching queue_lock and needs to perform unlock-relock dancing.
Unlinking is now wholly done from put_io_context() and fast path is
optimized by using the queue_lock the caller already holds, which is
by far the most common case. If the ioc accessed multiple devices,
it tries with trylock. In unlikely cases of fast path failure, it
falls back to full double-locking dance from workqueue.
Double-locking isn't the prettiest thing in the world but it's *far*
simpler and more understandable than RCU trick without adding any
meaningful overhead.
This still leaves a lot of now unnecessary RCU logics. Future patches
will trim them.
-v2: Vivek pointed out that cic->q was being dereferenced after
cic->release() was called. Updated to use local variable @this_q
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk_get_queue() is peculiar in that it returns 0 on success and 1 on
failure instead of 0 / -errno or boolean. Update it such that it
returns %true on success and %false on failure.
* Make sure the caller checks for the return value.
* Separate out __blk_get_queue() which doesn't check whether @q is
dead and put it in blk.h. This will be used later.
This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
cfq allocates per-queue id using ida and uses it to index cic radix
tree from io_context. Move it to q->id and allocate on queue init and
free on queue release. This simplifies cfq a bit and will allow for
further improvements of io context life-cycle management.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are a number of QUEUE_FLAG_DEAD tests. Add blk_queue_dead()
macro and use it.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only user left for blk_insert_request() is sx8 and it can be
trivially switched to use blk_execute_rq_nowait() - special requests
aren't included in io stat and sx8 doesn't use block layer tagging.
Switch sx8 and kill blk_insert_requeset().
This patch doesn't introduce any functional difference.
Only compile tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct request_queue is allocated with __GFP_ZERO so its "node" field is
zero before initialization. This causes an oops if node 0 is offline in
the page allocator because its zonelists are not initialized. From Dave
Young's dmesg:
SRAT: Node 1 PXM 2 0-d0000000
SRAT: Node 1 PXM 2 100000000-330000000
SRAT: Node 0 PXM 1 330000000-630000000
Initmem setup node 1 0000000000000000-000000000affb000
...
Built 1 zonelists in Node order, mobility grouping on.
...
BUG: unable to handle kernel paging request at 0000000000001c08
IP: [<ffffffff8111c355>] __alloc_pages_nodemask+0xb5/0x870
and __alloc_pages_nodemask+0xb5 translates to a NULL pointer on
zonelist->_zonerefs.
The fix is to initialize q->node at the time of allocation so the correct
node is passed to the slab allocator later.
Since blk_init_allocated_queue_node() is no longer needed, merge it with
blk_init_allocated_queue().
[rientjes@google.com: changelog, initializing q->node]
Cc: stable@vger.kernel.org [2.6.37+]
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Tested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
The <linux/module.h> pretty much brings in the kitchen sink along
with it, so it should be avoided wherever reasonably possible in
terms of being included from other commonly used <linux/something.h>
files, as it results in a measureable increase on compile times.
The worst culprit was probably device.h since it is used everywhere.
This file also had an implicit dependency/usage of mutex.h which was
masked by module.h, and is also fixed here at the same time.
There are over a dozen other headers that simply declare the
struct instead of pulling in the whole file, so follow their lead
and simply make it a few more.
Most of the implicit dependencies on module.h being present by
these headers pulling it in have been now weeded out, so we can
finally make this change with hopefully minimal breakage.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
blk_throtl interface is block internal and there's no reason to have
them in linux/blkdev.h. Move them to block/blk.h.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Thus spake Andrew Morton:
"And I have the usual maintainability whine. If someone comes up to
vmscan.c and sees it calling blk_start_plug(), how are they supposed to
work out why that call is there? They go look at the blk_start_plug()
definition and it is undocumented. I think we can do better than this?"
Adapted from the LWN article - http://lwn.net/Articles/438256/ by Jens
Axboe and from an earlier attempt by Shaohua Li to document blk-plug.
[akpm@linux-foundation.org: grammatical and spelling tweaks]
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is very little benefit in allowing to let a ->make_request
instance update the bios device and sector and loop around it in
__generic_make_request when we can archive the same through calling
generic_make_request from the driver and letting the loop in
generic_make_request handle it.
Note that various drivers got the return value from ->make_request and
returned non-zero values for errors.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Avoid the hacks need for request based device mappers currently by simply
exporting the symbol instead of trying to get it through the back door.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Cleaning up the code a little bit. attempt_plug_merge() traverses the plug
list anyway, we can do the request counting there, so stack size is reduced
a little bit.
The motivation here is I suspect if we should count the requests for each
queue (task could handle multiple disks in the meantime), but my test doesn't
show it's worthy doing. If somebody proves we should do it, below change
will make that more easier.
Signed-off-by: Shaohua Li <shli@kernel.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Commit ae1b153962, block: reimplement
FLUSH/FUA to support merge, introduced a performance regression when
running any sort of fsyncing workload using dm-multipath and certain
storage (in our case, an HP EVA). The test I ran was fs_mark, and it
dropped from ~800 files/sec on ext4 to ~100 files/sec. It turns out
that dm-multipath always advertised flush+fua support, and passed
commands on down the stack, where those flags used to get stripped off.
The above commit changed that behavior:
static inline struct request *__elv_next_request(struct request_queue *q)
{
struct request *rq;
while (1) {
- while (!list_empty(&q->queue_head)) {
+ if (!list_empty(&q->queue_head)) {
rq = list_entry_rq(q->queue_head.next);
- if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
- (rq->cmd_flags & REQ_FLUSH_SEQ))
- return rq;
- rq = blk_do_flush(q, rq);
- if (rq)
- return rq;
+ return rq;
}
Note that previously, a command would come in here, have
REQ_FLUSH|REQ_FUA set, and then get handed off to blk_do_flush:
struct request *blk_do_flush(struct request_queue *q, struct request *rq)
{
unsigned int fflags = q->flush_flags; /* may change, cache it */
bool has_flush = fflags & REQ_FLUSH, has_fua = fflags & REQ_FUA;
bool do_preflush = has_flush && (rq->cmd_flags & REQ_FLUSH);
bool do_postflush = has_flush && !has_fua && (rq->cmd_flags &
REQ_FUA);
unsigned skip = 0;
...
if (blk_rq_sectors(rq) && !do_preflush && !do_postflush) {
rq->cmd_flags &= ~REQ_FLUSH;
if (!has_fua)
rq->cmd_flags &= ~REQ_FUA;
return rq;
}
So, the flush machinery was bypassed in such cases (q->flush_flags == 0
&& rq->cmd_flags & (REQ_FLUSH|REQ_FUA)).
Now, however, we don't get into the flush machinery at all. Instead,
__elv_next_request just hands a request with flush and fua bits set to
the scsi_request_fn, even if the underlying request_queue does not
support flush or fua.
The agreed upon approach is to fix the flush machinery to allow
stacking. While this isn't used in practice (since there is only one
request-based dm target, and that target will now reflect the flush
flags of the underlying device), it does future-proof the solution, and
make it function as designed.
In order to make this work, I had to add a field to the struct request,
inside the flush structure (to store the original req->end_io). Shaohua
had suggested overloading the union with rb_node and completion_data,
but the completion data is used by device mapper and can also be used by
other drivers. So, I didn't see a way around the additional field.
I tested this patch on an HP EVA with both ext4 and xfs, and it recovers
the lost performance. Comments and other testers, as always, are
appreciated.
Cheers,
Jeff
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This moves the FC classes bsg code to the block layer and
makes it a lib so that other classes like iscsi and SAS can use it.
It is helpful because working with the request queue, bios,
creating scatterlists, etc are a pain that the LLD does not
have to worry about with normal IOs and should not have to
worry about for bsg requests.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Some systems benefit from completions always being steered to the strict
requester cpu rather than the looser "per-socket" steering that
blk_cpu_to_group() attempts by default. This is because the first
CPU in the group mask ends up being completely overloaded with work,
while the others (including the original submitter) has power left
to spare.
Allow the strict mode to be set by writing '2' to the sysfs control
file. This is identical to the scheme used for the nomerges file,
where '2' is a more aggressive setting than just being turned on.
echo 2 > /sys/block/<bdev>/queue/rq_affinity
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roland Dreier <roland@purestorage.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Reorder request_queue to remove 16 bytes of alignment padding in 64 bit
builds.
On my config this shrinks the size of this structure from 1608 to 1592
bytes and therefore needs one fewer cachelines.
Also trivially move the open bracket { to be on the same line as the
structure name to make it easier to grep.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
I'm often confused why not disable preempt when changing blk_plug list. It
would be better to add comments here in case others have the similar concerns.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
When I test fio script with big I/O depth, I found the total throughput drops
compared to some relative small I/O depth. The reason is the thread accumulates
big requests in its plug list and causes some delays (surely this depends
on CPU speed).
I thought we'd better have a threshold for requests. When a threshold reaches,
this means there is no request merge and queue lock contention isn't severe
when pushing per-task requests to queue, so the main advantages of blk plug
don't exist. We can force a plug list flush in this case.
With this, my test throughput actually increases and almost equals to small
I/O depth. Another side effect is irq off time decreases in blk_flush_plug_list()
for big I/O depth.
The BLK_MAX_REQUEST_COUNT is choosen arbitarily, but 16 is efficiently to
reduce lock contention to me. But I'm open here, 32 is ok in my test too.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
There is not a function rq_init but blk_rq_init in block/blk-core.c.
Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Since those defined functions require additional semicolon
from the caller, they could cause potential syntax errors
when used in if-else statements.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Since for-2.6.40/core was forked off the 2.6.39 devel tree, we've
had churn in the core area that makes it difficult to handle
patches for eg cfq or blk-throttle. Instead of requiring that they
be based in older versions with bugs that have been fixed later
in the rc cycle, merge in 2.6.39 final.
Also fixes up conflicts in the below files.
Conflicts:
drivers/block/paride/pcd.c
drivers/cdrom/viocd.c
drivers/ide/ide-cd.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
In some cases we would end up stacking discard_zeroes_data incorrectly.
Fix this by enabling the feature by default for stacking drivers and
clearing it for low-level drivers. Incorporating a device that does not
support dzd will then cause the feature to be disabled in the stacking
driver.
Also ensure that the maximum discard value does not overflow when
exported in sysfs and return 0 in the alignment and dzd fields for
devices that don't support discard.
Reported-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
In some drives, flush requests are non-queueable. When flush request is
running, normal read/write requests can't run. If block layer dispatches
such request, driver can't handle it and requeue it. Tejun suggested we
can hold the queue when flush is running. This can avoid unnecessary
requeue. Also this can improve performance. For example, we have
request flush1, write1, flush 2. flush1 is dispatched, then queue is
hold, write1 isn't inserted to queue. After flush1 is finished, flush2
will be dispatched. Since disk cache is already clean, flush2 will be
finished very soon, so looks like flush2 is folded to flush1.
In my test, the queue holding completely solves a regression introduced by
commit 53d63e6b0dfb95882ec0219ba6bbd50cde423794:
block: make the flush insertion use the tail of the dispatch list
It's not a preempt type request, in fact we have to insert it
behind requests that do specify INSERT_FRONT.
which causes about 20% regression running a sysbench fileio
workload.
Stable: 2.6.39 only
Cc: stable@kernel.org
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
flush request isn't queueable in some drives. Add a flag to let driver
notify block layer about this. We can optimize flush performance with the
knowledge.
Stable: 2.6.39 only
Cc: stable@kernel.org
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
We are currently using this flag to check whether it's safe
to call into ->request_fn(). If it is set, we punt to kblockd.
But we get a lot of false positives and excessive punts to
kblockd, which hurts performance.
The only real abuser of this infrastructure is SCSI. So export
the async queue run and convert SCSI over to use that. There's
room for improvement in that SCSI need not always use the async
call, but this fixes our performance issue and they can fix that
up in due time.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Instead of overloading __blk_run_queue to force an offload to kblockd
add a new blk_run_queue_async helper to do it explicitly. I've kept
the blk_queue_stopped check for now, but I suspect it's not needed
as the check we do when the workqueue items runs should be enough.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
MD can't use this since it really requires us to be able to
keep more than a single piece of state for the unplug. Commit
048c9374 added the required support for MD, so get rid of this
now unused code.
This reverts commit f75664570d.
Conflicts:
block/blk-core.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.
So allow arbitrary callbacks to be attached to the blk_plug.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Linus correctly observes that the most important dispatch cases
are now done from kblockd, this isn't ideal for latency reasons.
The original reason for switching dispatches out-of-line was to
avoid too deep a stack, so by _only_ letting the "accidental"
flush directly in schedule() be guarded by offload to kblockd,
we should be able to get the best of both worlds.
So add a blk_schedule_flush_plug() that offloads to kblockd,
and only use that from the schedule() path.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
For the explicit unplugging, we'd prefer to kick things off
immediately and not pay the penalty of the latency to switch
to kblockd. So let blk_finish_plug() do the run inline, while
the implicit-on-schedule-out unplug will punt to kblockd.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
It's a bit of a mess currently. task->plug is being cleared
and reset in __blk_finish_plug(), and blk_finish_plug() is
testing for a NULL plug which cannot happen even from schedule()
anymore since it uses blk_needs_flush_plug() to determine
whether to call into this function at all.
So get rid of some of the cruft.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
MD would like to know when a queue is unplugged, so it can flush
it's bitmap writes. Add such a callback.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The current block integrity (DIF/DIX) support in DM is verifying that
all devices' integrity profiles match during DM device resume (which
is past the point of no return). To some degree that is unavoidable
(stacked DM devices force this late checking). But for most DM
devices (which aren't stacking on other DM devices) the ideal time to
verify all integrity profiles match is during table load.
Introduce the notion of an "initialized" integrity profile: a profile
that was blk_integrity_register()'d with a non-NULL 'blk_integrity'
template. Add blk_integrity_is_initialized() to allow checking if a
profile was initialized.
Update DM integrity support to:
- check all devices with _initialized_ integrity profiles match
during table load; uninitialized profiles (e.g. for underlying DM
device(s) of a stacked DM device) are ignored.
- disallow a table load that would result in an integrity profile that
conflicts with a DM device's existing (in-use) integrity profile
- avoid clearing an existing integrity profile
- validate all integrity profiles match during resume; but if they
don't all we can do is report the mismatch (during resume we're past
the point of no return)
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This patch adds support for creating a queuing context outside
of the queue itself. This enables us to batch up pieces of IO
before grabbing the block device queue lock and submitting them to
the IO scheduler.
The context is created on the stack of the process and assigned in
the task structure, so that we can auto-unplug it if we hit a schedule
event.
The current queue plugging happens implicitly if IO is submitted to
an empty device, yet callers have to remember to unplug that IO when
they are going to wait for it. This is an ugly API and has caused bugs
in the past. Additionally, it requires hacks in the vm (->sync_page()
callback) to handle that logic. By switching to an explicit plugging
scheme we make the API a lot nicer and can get rid of the ->sync_page()
hack in the vm.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This merge creates two set of conflicts. One is simple context
conflicts caused by removal of throtl_scheduled_delayed_work() in
for-linus and removal of throtl_shutdown_timer_wq() in
for-2.6.39/core.
The other is caused by commit 255bb490c8 (block: blk-flush shouldn't
call directly into q->request_fn() __blk_run_queue()) in for-linus
crashing with FLUSH reimplementation in for-2.6.39/core. The conflict
isn't trivial but the resolution is straight-forward.
* __blk_run_queue() calls in flush_end_io() and flush_data_end_io()
should be called with @force_kblockd set to %true.
* elv_insert() in blk_kick_flush() should use
%ELEVATOR_INSERT_REQUEUE.
Both changes are to avoid invoking ->request_fn() directly from
request completion path and closely match the changes in the commit
255bb490c8.
Signed-off-by: Tejun Heo <tj@kernel.org>
Move blk_throtl_exit() in blk_cleanup_queue() as blk_throtl_exit() is
written in such a way that it needs queue lock. In blk_release_queue()
there is no gurantee that ->queue_lock is still around.
Initially blk_throtl_exit() was in blk_cleanup_queue() but Ingo reported
one problem.
https://lkml.org/lkml/2010/10/23/86
And a quick fix moved blk_throtl_exit() to blk_release_queue().
commit 7ad58c0286
Author: Jens Axboe <jaxboe@fusionio.com>
Date: Sat Oct 23 20:40:26 2010 +0200
block: fix use-after-free bug in blk throttle code
This patch reverts above change and does not try to shutdown the
throtl work in blk_sync_queue(). By avoiding call to
throtl_shutdown_timer_wq() from blk_sync_queue(), we should also avoid
the problem reported by Ingo.
blk_sync_queue() seems to be used only by md driver and it seems to be
using it to make sure q->unplug_fn is not called as md registers its
own unplug functions and it is about to free up the data structures
used by unplug_fn(). Block throttle does not call back into unplug_fn()
or into md. So there is no need to cancel blk throttle work.
In fact I think cancelling block throttle work is bad because it might
happen that some bios are throttled and scheduled to be dispatched later
with the help of pending work and if work is cancelled, these bios might
never be dispatched.
Block layer also uses blk_sync_queue() during blk_cleanup_queue() and
blk_release_queue() time. That should be safe as we are also calling
blk_throtl_exit() which should make sure all the throttling related
data structures are cleaned up.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
__blk_run_queue() automatically either calls q->request_fn() directly
or schedules kblockd depending on whether the function is recursed.
blk-flush implementation needs to be able to explicitly choose
kblockd. Add @force_kblockd.
All the current users are converted to specify %false for the
parameter and this patch doesn't introduce any behavior change.
stable: This is prerequisite for fixing ide oops caused by the new
blk-flush implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
o Dominik Klein reported a system hang issue while doing some blkio
throttling testing.
https://lkml.org/lkml/2011/2/24/173
o Some tracing revealed that CFQ was not dispatching any more jobs as
queue unplug was not happening. And queue unplug was not happening
because unplug work was not being called as there was one throttling
work on same cpu which as not finished yet. And throttling work had not
finished as it was tyring to dispatch a bio to CFQ but all the request
descriptors were consume to it was put to sleep.
o So basically it is a cyclic dependecny between CFQ unplug work and
throtl dispatch work. Tejun suggested that use separate workqueue for
such cases.
o This patch uses a separate workqueue for throttle related work and
does not rely on kblockd workqueue anymore.
Cc: stable@kernel.org
Reported-by: Dominik Klein <dk@in-telegence.net>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Flush requests are never put on the IO scheduler. Convert request
structure's elevator_private* into an array and have the flush fields
share a union with it.
Reclaim the space lost in 'struct request' by moving 'completion_data'
back in the union with 'rb_node'.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The current FLUSH/FUA support has evolved from the implementation
which had to perform queue draining. As such, sequencing is done
queue-wide one flush request after another. However, with the
draining requirement gone, there's no reason to keep the queue-wide
sequential approach.
This patch reimplements FLUSH/FUA support such that each FLUSH/FUA
request is sequenced individually. The actual FLUSH execution is
double buffered and whenever a request wants to execute one for either
PRE or POSTFLUSH, it queues on the pending queue. Once certain
conditions are met, a flush request is issued and on its completion
all pending requests proceed to the next sequence.
This allows arbitrary merging of different type of flushes. How they
are merged can be primarily controlled and tuned by adjusting the
above said 'conditions' used to determine when to issue the next
flush.
This is inspired by Darrick's patches to merge multiple zero-data
flushes which helps workloads with highly concurrent fsync requests.
* As flush requests are never put on the IO scheduler, request fields
used for flush share space with rq->rb_node. rq->completion_data is
moved out of the union. This increases the request size by one
pointer.
As rq->elevator_private* are used only by the iosched too, it is
possible to reduce the request size further. However, to do that,
we need to modify request allocation path such that iosched data is
not allocated for flush requests.
* FLUSH/FUA processing happens on insertion now instead of dispatch.
- Comments updated as per Vivek and Mike.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
/proc/diskstats would display a strange output as follows.
$ cat /proc/diskstats |grep sda
8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
~~~~~~~~~~
8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92
8 4 sda4 4 0 8 0 0 0 0 0 0 0 0
8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137
Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.
The detailed root cause is as follows.
Assuming that there are two partition, sda1 and sda2.
1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
is 0 and sda2's one is 1.
| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------
2. A bio belongs to sda1 is issued and is merged into the request mentioned on
step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
from sda2 region to sda1 region. However the two partition's
hd_struct->in_flight are not changed.
| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------
3. The request is finished and blk_account_io_done() is called. In this case,
sda2's hd_struct->in_flight, not a sda1's one, is decremented.
| hd_struct->in_flight
---------------------------
sda1 | -1
sda2 | 1
---------------------------
The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.
Also add a refcount to struct hd_struct to keep the partition in
memory as long as users exist. We use kref_test_and_get() to ensure
we don't add a reference to a partition which is going away.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Implement blk_limits_max_hw_sectors() and make
blk_queue_max_hw_sectors() a wrapper around it.
DM needs this to avoid setting queue_limits' max_hw_sectors and
max_sectors directly. dm_set_device_limits() now leverages
blk_limits_max_hw_sectors() logic to establish the appropriate
max_hw_sectors minimum (PAGE_SIZE). Fixes issue where DM was
incorrectly setting max_sectors rather than max_hw_sectors (which
caused dm_merge_bvec()'s max_hw_sectors check to be ineffective).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.
There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.
The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.
Reported-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Currently, media presence polling for removeable block devices is done
from userland. There are several issues with this.
* Polling is done by periodically opening the device. For SCSI
devices, the command sequence generated by such action involves a
few different commands including TEST_UNIT_READY. This behavior,
while perfectly legal, is different from Windows which only issues
single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some
ATAPI devices lock up after being periodically queried such command
sequences.
* There is no reliable and unintrusive way for a userland program to
tell whether the target device is safe for media presence polling.
For example, polling for media presence during an on-going burning
session can make it fail. The polling program can avoid this by
opening the device with O_EXCL but then it risks making a valid
exclusive user of the device fail w/ -EBUSY.
* Userland polling is unnecessarily heavy and in-kernel implementation
is lighter and better coordinated (workqueue, timer slack).
This patch implements framework for in-kernel disk event handling,
which includes media presence polling.
* bdops->check_events() is added, which supercedes ->media_changed().
It should check whether there's any pending event and return if so.
Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and
DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be
called parallelly.
* gendisk->events and ->async_events are added. These should be
initialized by block driver before passing the device to add_disk().
The former contains the mask of all supported events and the latter
the mask of all events which the device can report without polling.
/sys/block/*/events[_async] export these to userland.
* Kernel parameter block.events_dfl_poll_msecs controls the system
polling interval (default is 0 which means disable) and
/sys/block/*/events_poll_msecs control polling intervals for
individual devices (default is -1 meaning use system setting). Note
that if a device can report all supported events asynchronously and
its polling interval isn't explicitly set, the device won't be
polled regardless of the system polling interval.
* If a device is opened exclusively with write access, event checking
is automatically disabled until all write exclusive accesses are
released.
* There are event 'clearing' events. For example, both of currently
defined events are cleared after the device has been successfully
opened. This information is passed to ->check_events() callback
using @clearing argument as a hint.
* Event checking is always performed from system_nrt_wq and timer
slack is set to 25% for polling.
* Nothing changes for drivers which implement ->media_changed() but
not ->check_events(). Going forward, all drivers will be converted
to ->check_events() and ->media_change() will be dropped.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
There's no reason for register_disk() and del_gendisk() to be in
fs/partitions/check.c. Move both to genhd.c. While at it, collapse
unlink_gendisk(), which was artificially in a separate function due to
genhd.c / check.c split, into del_gendisk().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
REQ_HARDBARRIER is dead now, so remove the leftovers. What's left
at this point is:
- various checks inside the block layer.
- sanity checks in bio based drivers.
- now unused bio_empty_barrier helper.
- Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
but Xen really needs to sort out it's barrier situaton.
- setting of ordered tags in uas - dead code copied from old scsi
drivers.
- scsi different retry for barriers - it's dead and should have been
removed when flushes were converted to FS requests.
- blktrace handling of barriers - removed. Someone who knows blktrace
better should add support for REQ_FLUSH and REQ_FUA, though.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This is done the same way as helper sb_issue_discard for
blkdev_issue_discard.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This reverts commit 7681bfeecc.
Conflicts:
include/linux/genhd.h
It has numerous issues with the cleanup path and non-elevator
devices. Revert it for now so we can come up with a clean
version without rushing things.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
xen-blkfront: disable barrier/flush write support
Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
block: remove BLKDEV_IFL_WAIT
aic7xxx_old: removed unused 'req' variable
block: remove the BH_Eopnotsupp flag
block: remove the BLKDEV_IFL_BARRIER flag
block: remove the WRITE_BARRIER flag
swap: do not send discards as barriers
fat: do not send discards as barriers
ext4: do not send discards as barriers
jbd2: replace barriers with explicit flush / FUA usage
jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
jbd: replace barriers with explicit flush / FUA usage
nilfs2: replace barriers with explicit flush / FUA usage
reiserfs: replace barriers with explicit flush / FUA usage
gfs2: replace barriers with explicit flush / FUA usage
btrfs: replace barriers with explicit flush / FUA usage
xfs: replace barriers with explicit flush / FUA usage
block: pass gfp_mask and flags to sb_issue_discard
dm: convey that all flushes are processed as empty
...
/proc/diskstats would display a strange output as follows.
$ cat /proc/diskstats |grep sda
8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
~~~~~~~~~~
8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92
8 4 sda4 4 0 8 0 0 0 0 0 0 0 0
8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137
Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.
The detailed root cause is as follows.
Assuming that there are two partition, sda1 and sda2.
1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
is 0 and sda2's one is 1.
| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------
2. A bio belongs to sda1 is issued and is merged into the request mentioned on
step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
from sda2 region to sda1 region. However the two partition's
hd_struct->in_flight are not changed.
| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------
3. The request is finished and blk_account_io_done() is called. In this case,
sda2's hd_struct->in_flight, not a sda1's one, is decremented.
| hd_struct->in_flight
---------------------------
sda1 | -1
sda2 | 1
---------------------------
The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.
When reloading partition tables, quiesce IO to ensure that no
request references to the partition struct exists. When it is safe
to free the partition table, the IO for that device is restarted
again.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Physical block size was declared unsigned int to accomodate the maximum
size reported by READ CAPACITY(16). Make sure we use the right type in
the related functions.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
All the blkdev_issue_* helpers can only sanely be used for synchronous
caller. To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead. So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout. For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
o Actual implementation of throttling policy in block layer. Currently it
implements READ and WRITE bytes per second throttling logic. IOPS throttling
comes in later patches.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Bart Van Assche