06 Sep, 2019
1 commit
-
When elevator_init_mq() is called from blk_mq_init_allocated_queue(),
the only information known about the device is the number of hardware
queues as the block device scan by the device driver is not completed
yet for most drivers. The device type and elevator required features
are not set yet, preventing to correctly select the default elevator
most suitable for the device.This currently affects all multi-queue zoned block devices which default
to the "none" elevator instead of the required "mq-deadline" elevator.
These drives currently include host-managed SMR disks connected to a
smartpqi HBA and null_blk block devices with zoned mode enabled.
Upcoming NVMe Zoned Namespace devices will also be affected.Fix this by adding the boolean elevator_init argument to
blk_mq_init_allocated_queue() to control the execution of
elevator_init_mq(). Two cases exist:
1) elevator_init = false is used for calls to
blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this
case, a call to elevator_init_mq() is added to __device_add_disk(),
resulting in the delayed initialization of the queue elevator
after the device driver finished probing the device information. This
effectively allows elevator_init_mq() access to more information
about the device.
2) elevator_init = true preserves the current behavior of initializing
the elevator directly from blk_mq_init_allocated_queue(). This case
is used for the special request based DM devices where the device
gendisk is created before the queue initialization and device
information (e.g. queue limits) is already known when the queue
initialization is executed.Additionally, to make sure that the elevator initialization is never
done while requests are in-flight (there should be none when the device
driver calls device_add_disk()), freeze and quiesce the device request
queue before calling blk_mq_init_sched() in elevator_init_mq().Reviewed-by: Ming Lei
Signed-off-by: Damien Le Moal
Signed-off-by: Jens Axboe
17 Jul, 2019
1 commit
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The runtime configurable module parameter files are located under
/sys/module/MODULENAME/parameters, not /sys/module/MODULENAME.Cc: Jens Axboe
Signed-off-by: Akinobu Mita
Signed-off-by: Jens Axboe
15 Jun, 2019
1 commit
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Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.So, replace the following form:
sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0])
with:
struct_size(new_ptbl, part, target)
Also, notice that variable size is unnecessary, hence it is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Jens Axboe
01 Jun, 2019
1 commit
-
This patch avoids that the kernel-doc tool warns about this function
header when building with W=1.Reviewed-by: Chaitanya Kulkarni
Signed-off-by: Bart Van Assche
Signed-off-by: Jens Axboe
01 May, 2019
1 commit
-
Various block layer files do not have any licensing information at all.
Add SPDX tags for the default kernel GPLv2 license to those.Reviewed-by: Chaitanya Kulkarni
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
22 Apr, 2019
1 commit
-
commit 2da78092dda "block: Fix dev_t minor allocation lifetime"
specifically moved blk_free_devt(dev->devt) call to part_release()
to avoid reallocating device number before the device is fully
shutdown.However, it can cause use-after-free on gendisk in get_gendisk().
We use md device as example to show the race scenes:Process1 Worker Process2
md_free
blkdev_open
del_gendisk
add delete_partition_work_fn() to wq
__blkdev_get
get_gendisk
put_disk
disk_release
kfree(disk)
find part from ext_devt_idr
get_disk_and_module(disk)
cause use after freedelete_partition_work_fn
put_device(part)
part_release
remove part from ext_devt_idrBefore is removed from ext_devt_idr by
delete_partition_work_fn(), we can find the devt and then access
gendisk by hd_struct pointer. But, if we access the gendisk after
it have been freed, it can cause in use-after-freeon gendisk in
get_gendisk().We fix this by adding a new helper blk_invalidate_devt() in
delete_partition() and del_gendisk(). It replaces hd_struct
pointer in idr with value 'NULL', and deletes the entry from
idr in part_release() as we do now.Thanks to Jan Kara for providing the solution and more clear comments
for the code.Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime")
Cc: Al Viro
Reviewed-by: Bart Van Assche
Reviewed-by: Keith Busch
Reviewed-by: Jan Kara
Suggested-by: Jan Kara
Signed-off-by: Yufen Yu
Signed-off-by: Jens Axboe
13 Apr, 2019
3 commits
-
Drivers now report to the block layer if they support media change
events. If this is not the case, there's no need to allocate the event
structure, and all event handling code can effectively be skipped. This
simplifies code flow in particular for non-removable sd devices.This effectively reverts commit 75e3f3ee3c64 ("block: always allocate
genhd->ev if check_events is implemented").The sysfs files for the events are kept in place even if no events are
supported, as user space may rely on them being present. The only
difference is that an error code is now returned if the user tries to
set poll_msecs.Reviewed-by: Hannes Reinecke
Reviewed-by: Christoph Hellwig
Signed-off-by: Martin Wilck
Signed-off-by: Jens Axboe -
Currently, an empty disk->events field tells the block layer not to
forward media change events to user space. This was done in commit
7c88a168da80 ("block: don't propagate unlisted DISK_EVENTs to userland")
in order to avoid events from "fringe" drivers to be forwarded to user
space. By doing so, the block layer lost the information which events
were supported by a particular block device, and most importantly,
whether or not a given device supports media change events at all.Prepare for not interpreting the "events" field this way in the future
any more. This is done by adding an additional field "event_flags" to
struct gendisk, and two flag bits that can be set to have the device
treated like one that had the "events" field set to a non-zero value
before. This applies only to the sd and sr drivers, which are changed to
set the new flags.The new flags are DISK_EVENT_FLAG_POLL to enforce polling of the device
for synchronous events, and DISK_EVENT_FLAG_UEVENT to tell the
blocklayer to generate udev events from kernel events.In order to add the event_flags field to struct gendisk, the events
field is converted to an "unsigned short"; it doesn't need to hold
values bigger than 2 anyway.This patch doesn't change behavior.
Reviewed-by: Christoph Hellwig
Signed-off-by: Martin Wilck
Signed-off-by: Jens Axboe -
The async_events field, intended to be used for drivers that support
asynchronous notifications about disk events (aka media change events),
isn't currently used by any driver, and apparently that has been that
way for a long time (if not forever). Remove it.Reviewed-by: Hannes Reinecke
Reviewed-by: Christoph Hellwig
Signed-off-by: Martin Wilck
Signed-off-by: Jens Axboe
01 Mar, 2019
2 commits
-
Replace hard coded function name register_blkdev with __func__, to
improve robustness and to conform to the Linux kernel coding
style. Issue found using checkpatch.Signed-off-by: Keyur Patel
Signed-off-by: Jens Axboe -
If __device_add_disk-->bdi_register_owner-->bdi_register-->
bdi_register_va-->device_create_vargs fails, bdi->dev is still
NULL, __device_add_disk-->register_disk will visit bdi->dev->kobj.
This patch fixes that.Signed-off-by: zhengbin
Signed-off-by: Jens Axboe
10 Dec, 2018
4 commits
-
The previous patches deleted all the code that needed the second value
returned from part_in_flight - now the kernel only uses the first value.Consequently, part_in_flight (and blk_mq_in_flight) may be changed so that
it only returns one value.This patch just refactors the code, there's no functional change.
Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
Signed-off-by: Jens Axboe -
Now when part_round_stats is gone, we can switch to per-cpu in-flight
counters.We use the local-atomic type local_t, so that if part_inc_in_flight or
part_dec_in_flight is reentrantly called from an interrupt, the value will
be correct.The other counters could be corrupted due to reentrant interrupt, but the
corruption only results in slight counter skew - the in_flight counter
must be exact, so it needs local_t.Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
Signed-off-by: Jens Axboe -
We want to convert to per-cpu in_flight counters.
The function part_round_stats needs the in_flight counter every jiffy, it
would be too costly to sum all the percpu variables every jiffy, so it
must be deleted. part_round_stats is used to calculate two counters -
time_in_queue and io_ticks.time_in_queue can be calculated without part_round_stats, by adding the
duration of the I/O when the I/O ends (the value is almost as exact as the
previously calculated value, except that time for in-progress I/Os is not
counted).io_ticks can be approximated by increasing the value when I/O is started
or ended and the jiffies value has changed. If the I/Os take less than a
jiffy, the value is as exact as the previously calculated value. If the
I/Os take more than a jiffy, io_ticks can drift behind the previously
calculated value.Signed-off-by: Mikulas Patocka
Signed-off-by: Mike Snitzer
Signed-off-by: Jens Axboe -
All of part_stat_* and related methods are used with preempt disabled,
so there is no need to pass cpu around to allow of them. Just call
smp_processor_id() as needed.Suggested-by: Jens Axboe
Signed-off-by: Mike Snitzer
Signed-off-by: Jens Axboe
16 Nov, 2018
1 commit
-
Various spots check for q->mq_ops being non-NULL, but provide
a helper to do this instead.Where the ->mq_ops != NULL check is redundant, remove it.
Since mq == rq-based now that legacy is gone, get rid of the
queue_is_rq_based() and just use queue_is_mq() everywhere.Reviewed-by: Christoph Hellwig
Signed-off-by: Jens Axboe
01 Oct, 2018
1 commit
-
Merge -rc6 in, for two reasons:
1) Resolve a trivial conflict in the blk-mq-tag.c documentation
2) A few important regression fixes went into upstream directly, so
they aren't in the 4.20 branch.Signed-off-by: Jens Axboe
* tag 'v4.19-rc6': (780 commits)
Linux 4.19-rc6
MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c
cpufreq: qcom-kryo: Fix section annotations
perf/core: Add sanity check to deal with pinned event failure
xen/blkfront: correct purging of persistent grants
Revert "xen/blkfront: When purging persistent grants, keep them in the buffer"
selftests/powerpc: Fix Makefiles for headers_install change
blk-mq: I/O and timer unplugs are inverted in blktrace
dax: Fix deadlock in dax_lock_mapping_entry()
x86/boot: Fix kexec booting failure in the SEV bit detection code
bcache: add separate workqueue for journal_write to avoid deadlock
drm/amd/display: Fix Edid emulation for linux
drm/amd/display: Fix Vega10 lightup on S3 resume
drm/amdgpu: Fix vce work queue was not cancelled when suspend
Revert "drm/panel: Add device_link from panel device to DRM device"
xen/blkfront: When purging persistent grants, keep them in the buffer
clocksource/drivers/timer-atmel-pit: Properly handle error cases
block: fix deadline elevator drain for zoned block devices
ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge
drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set
...Signed-off-by: Jens Axboe
28 Sep, 2018
1 commit
-
Update device_add_disk() to take an 'groups' argument so that
individual drivers can register a device with additional sysfs
attributes.
This avoids race condition the driver would otherwise have if these
groups were to be created with sysfs_add_groups().Signed-off-by: Martin Wilck
Signed-off-by: Hannes Reinecke
Reviewed-by: Christoph Hellwig
Reviewed-by: Bart Van Assche
Signed-off-by: Jens Axboe
22 Sep, 2018
1 commit
-
Klaus Kusche reported that the I/O busy time in /proc/diskstats was not
updating properly on 4.18. This is because we started using ktime to
track elapsed time, and we convert nanoseconds to jiffies when we update
the partition counter. However, this gets rounded down, so any I/Os that
take less than a jiffy are not accounted for. Previously in this case,
the value of jiffies would sometimes increment while we were doing I/O,
so at least some I/Os were accounted for.Let's convert the stats to use nanoseconds internally. We still report
milliseconds as before, now more accurately than ever. The value is
still truncated to 32 bits for backwards compatibility.Fixes: 522a777566f5 ("block: consolidate struct request timestamp fields")
Cc: stable@vger.kernel.org
Reported-by: Klaus Kusche
Signed-off-by: Omar Sandoval
Signed-off-by: Jens Axboe
18 Jul, 2018
2 commits
-
Add tracking of REQ_OP_DISCARD ios to the partition statistics and
append them to the various stat files in /sys as well as
/proc/diskstats. These are tracked with the same four stats as reads
and writes:Number of discard ios completed.
Number of discard ios merged
Number of discard sectors completed
Milliseconds spent on discard requestsThis is done via adding a new STAT_DISCARD define to genhd.h and then
using it to index that stat field for discard requests.tj: Refreshed on top of v4.17 and other previous updates.
Signed-off-by: Michael Callahan
Signed-off-by: Tejun Heo
Cc: Andy Newell
Signed-off-by: Jens Axboe -
Add defines for STAT_READ and STAT_WRITE for indexing the partition
stat entries. This clarifies some fs/ code which has hardcoded 1 for
STAT_WRITE and will make it easier to extend the stats with additional
fields.tj: Refreshed on top of v4.17.
Signed-off-by: Michael Callahan
Signed-off-by: Tejun Heo
Cc: "Theodore Ts'o"
Cc: Jaegeuk Kim
Signed-off-by: Jens Axboe
05 Jun, 2018
1 commit
-
Pull procfs updates from Al Viro:
"Christoph's proc_create_... cleanups series"* 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (44 commits)
xfs, proc: hide unused xfs procfs helpers
isdn/gigaset: add back gigaset_procinfo assignment
proc: update SIZEOF_PDE_INLINE_NAME for the new pde fields
tty: replace ->proc_fops with ->proc_show
ide: replace ->proc_fops with ->proc_show
ide: remove ide_driver_proc_write
isdn: replace ->proc_fops with ->proc_show
atm: switch to proc_create_seq_private
atm: simplify procfs code
bluetooth: switch to proc_create_seq_data
netfilter/x_tables: switch to proc_create_seq_private
netfilter/xt_hashlimit: switch to proc_create_{seq,single}_data
neigh: switch to proc_create_seq_data
hostap: switch to proc_create_{seq,single}_data
bonding: switch to proc_create_seq_data
rtc/proc: switch to proc_create_single_data
drbd: switch to proc_create_single
resource: switch to proc_create_seq_data
staging/rtl8192u: simplify procfs code
jfs: simplify procfs code
...
25 May, 2018
1 commit
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Convert the S_ symbolic permissions to their octal equivalents as
using octal and not symbolic permissions is preferred by many as more
readable.see: https://lkml.org/lkml/2016/8/2/1945
Done with automated conversion via:
$ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplaceMiscellanea:
o Wrapped modified multi-line calls to a single line where appropriate
o Realign modified multi-line calls to open parenthesisSigned-off-by: Joe Perches
Signed-off-by: Jens Axboe
16 May, 2018
1 commit
-
Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.All trivial callers converted over.
Signed-off-by: Christoph Hellwig
26 Apr, 2018
1 commit
-
When the blk-mq inflight implementation was added, /proc/diskstats was
converted to use it, but /sys/block/$dev/inflight was not. Fix it by
adding another helper to count in-flight requests by data direction.Fixes: f299b7c7a9de ("blk-mq: provide internal in-flight variant")
Signed-off-by: Omar Sandoval
Signed-off-by: Jens Axboe
16 Mar, 2018
1 commit
-
register_blkdev() and __register_chrdev_region() treat the major
number as an unsigned int. So print it the same way to avoid
absurd error statements such as:
"... major requested (-1) is greater than the maximum (511) ..."
(and also fix off-by-one bugs in the error prints).While at it, also update the comment describing register_blkdev().
Signed-off-by: Srivatsa S. Bhat
Reviewed-by: Logan Gunthorpe
Signed-off-by: Greg Kroah-Hartman
27 Feb, 2018
4 commits
-
When two blkdev_open() calls for a partition race with device removal
and recreation, we can hit BUG_ON(!bd_may_claim(bdev, whole, holder)) in
blkdev_open(). The race can happen as follows:CPU0 CPU1 CPU2
del_gendisk()
bdev_unhash_inode(part1);blkdev_open(part1, O_EXCL) blkdev_open(part1, O_EXCL)
bdev = bd_acquire() bdev = bd_acquire()
blkdev_get(bdev)
bd_start_claiming(bdev)
- finds old inode 'whole'
bd_prepare_to_claim() -> 0
bdev_unhash_inode(whole);
blkdev_get(bdev);
bd_start_claiming(bdev)
- finds new inode 'whole'
bd_prepare_to_claim()
- this also succeeds as we have
different 'whole' here...
- bad things happen now as we
have two exclusive openers of
the same bdevThe problem here is that block device opens can see various intermediate
states while gendisk is shutting down and then being recreated.We fix the problem by introducing new lookup_sem in gendisk that
synchronizes gendisk deletion with get_gendisk() and furthermore by
making sure that get_gendisk() does not return gendisk that is being (or
has been) deleted. This makes sure that once we ever manage to look up
newly created bdev inode, we are also guaranteed that following
get_gendisk() will either return failure (and we fail open) or it
returns gendisk for the new device and following bdget_disk() will
return new bdev inode (i.e., blkdev_open() follows the path as if it is
completely run after new device is created).Reported-and-analyzed-by: Hou Tao
Tested-by: Hou Tao
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
Add a proper counterpart to get_disk_and_module() -
put_disk_and_module(). Currently it is opencoded in several places.Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
Rename get_disk() to get_disk_and_module() to make sure what the
function does. It's not a great name but at least it is now clear that
put_disk() is not it's counterpart.Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe -
Commit 8ddcd653257c "block: introduce GENHD_FL_HIDDEN" added handling of
hidden devices to get_gendisk() but forgot to drop module reference
which is also acquired by get_disk(). Drop the reference as necessary.Arguably the function naming here is misleading as put_disk() is *not*
the counterpart of get_disk() but let's fix that in the follow up
commit since that will be more intrusive.Fixes: 8ddcd653257c18a669fcb75ee42c37054908e0d6
CC: Christoph Hellwig
Signed-off-by: Jan Kara
Signed-off-by: Jens Axboe
15 Jan, 2018
2 commits
-
Since I can remember DM has forced the block layer to allow the
allocation and initialization of the request_queue to be distinct
operations. Reason for this is block/genhd.c:add_disk() has requires
that the request_queue (and associated bdi) be tied to the gendisk
before add_disk() is called -- because add_disk() also deals with
exposing the request_queue via blk_register_queue().DM's dynamic creation of arbitrary device types (and associated
request_queue types) requires the DM device's gendisk be available so
that DM table loads can establish a master/slave relationship with
subordinate devices that are referenced by loaded DM tables -- using
bd_link_disk_holder(). But until these DM tables, and their associated
subordinate devices, are known DM cannot know what type of request_queue
it needs -- nor what its queue_limits should be.This chicken and egg scenario has created all manner of problems for DM
and, at times, the block layer.Summary of changes:
- Add device_add_disk_no_queue_reg() and add_disk_no_queue_reg() variant
that drivers may use to add a disk without also calling
blk_register_queue(). Driver must call blk_register_queue() once its
request_queue is fully initialized.- Return early from blk_unregister_queue() if QUEUE_FLAG_REGISTERED
is not set. It won't be set if driver used add_disk_no_queue_reg()
but driver encounters an error and must del_gendisk() before calling
blk_register_queue().- Export blk_register_queue().
These changes allow DM to use add_disk_no_queue_reg() to anchor its
gendisk as the "master" for master/slave relationships DM must establish
with subordinate devices referenced in DM tables that get loaded. Once
all "slave" devices for a DM device are known its request_queue can be
properly initialized and then advertised via sysfs -- important
improvement being that no request_queue resource initialization
performed by blk_register_queue() is missed for DM devices anymore.Signed-off-by: Mike Snitzer
Reviewed-by: Ming Lei
Signed-off-by: Jens Axboe -
device_add_disk() will only call bdi_register_owner() if
!GENHD_FL_HIDDEN, so it follows that del_gendisk() should only call
bdi_unregister() if !GENHD_FL_HIDDEN.Found with code inspection. bdi_unregister() won't do any harm if
bdi_register_owner() wasn't used but best to avoid the unnecessary
call to bdi_unregister().Fixes: 8ddcd65325 ("block: introduce GENHD_FL_HIDDEN")
Signed-off-by: Mike Snitzer
Reviewed-by: Ming Lei
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe
20 Nov, 2017
2 commits
-
Fix typo in error message.
Signed-off-by: Randy Dunlap
Signed-off-by: Jens Axboe -
device_add_disk need do more safety error handle, so this patch just
add WARN_ON.Reviewed-by: Jan Kara
Signed-off-by: weiping zhangAdapted for current series by me.
Signed-off-by: Jens Axboe
15 Nov, 2017
1 commit
-
Pull core block layer updates from Jens Axboe:
"This is the main pull request for block storage for 4.15-rc1.Nothing out of the ordinary in here, and no API changes or anything
like that. Just various new features for drivers, core changes, etc.
In particular, this pull request contains:- A patch series from Bart, closing the whole on blk/scsi-mq queue
quescing.- A series from Christoph, building towards hidden gendisks (for
multipath) and ability to move bio chains around.- NVMe
- Support for native multipath for NVMe (Christoph).
- Userspace notifications for AENs (Keith).
- Command side-effects support (Keith).
- SGL support (Chaitanya Kulkarni)
- FC fixes and improvements (James Smart)
- Lots of fixes and tweaks (Various)- bcache
- New maintainer (Michael Lyle)
- Writeback control improvements (Michael)
- Various fixes (Coly, Elena, Eric, Liang, et al)- lightnvm updates, mostly centered around the pblk interface
(Javier, Hans, and Rakesh).- Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)
- Writeback series that fix the much discussed hundreds of millions
of sync-all units. This goes all the way, as discussed previously
(me).- Fix for missing wakeup on writeback timer adjustments (Yafang
Shao).- Fix laptop mode on blk-mq (me).
- {mq,name} tupple lookup for IO schedulers, allowing us to have
alias names. This means you can use 'deadline' on both !mq and on
mq (where it's called mq-deadline). (me).- blktrace race fix, oopsing on sg load (me).
- blk-mq optimizations (me).
- Obscure waitqueue race fix for kyber (Omar).
- NBD fixes (Josef).
- Disable writeback throttling by default on bfq, like we do on cfq
(Luca Miccio).- Series from Ming that enable us to treat flush requests on blk-mq
like any other request. This is a really nice cleanup.- Series from Ming that improves merging on blk-mq with schedulers,
getting us closer to flipping the switch on scsi-mq again.- BFQ updates (Paolo).
- blk-mq atomic flags memory ordering fixes (Peter Z).
- Loop cgroup support (Shaohua).
- Lots of minor fixes from lots of different folks, both for core and
driver code"* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
nvme: fix visibility of "uuid" ns attribute
blk-mq: fixup some comment typos and lengths
ide: ide-atapi: fix compile error with defining macro DEBUG
blk-mq: improve tag waiting setup for non-shared tags
brd: remove unused brd_mutex
blk-mq: only run the hardware queue if IO is pending
block: avoid null pointer dereference on null disk
fs: guard_bio_eod() needs to consider partitions
xtensa/simdisk: fix compile error
nvme: expose subsys attribute to sysfs
nvme: create 'slaves' and 'holders' entries for hidden controllers
block: create 'slaves' and 'holders' entries for hidden gendisks
nvme: also expose the namespace identification sysfs files for mpath nodes
nvme: implement multipath access to nvme subsystems
nvme: track shared namespaces
nvme: introduce a nvme_ns_ids structure
nvme: track subsystems
block, nvme: Introduce blk_mq_req_flags_t
block, scsi: Make SCSI quiesce and resume work reliably
block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
...
11 Nov, 2017
2 commits
-
It is possible that the pointer disk can be null and hence
we can get a null pointer deference when accessing disk->flags.
Add a null pointer check to avoid the dereference.Detected by CoverityScan, CID#1461133 ("Explicit null dereferenced")
Fixes: 8ddcd653257c ("block: introduce GENHD_FL_HIDDEN")
Reviewed-by: Christoph Hellwig
Signed-off-by: Colin Ian King
Signed-off-by: Jens Axboe -
When creating nvme multipath devices we should populate the 'slaves' and
'holders' directorys properly to aid userspace topology detection.Signed-off-by: Hannes Reinecke
[hch: split from a larger patch]
Reviewed-by: Keith Busch
Reviewed-by: Martin K. Petersen
Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
04 Nov, 2017
2 commits
-
With this flag a driver can create a gendisk that can be used for I/O
submission inside the kernel, but which is not registered as user
facing block device. This will be useful for the NVMe multipath
implementation.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe -
The hidden gendisks introduced in the next patch need to keep the dev
field in their struct device empty so that udev won't try to create
block device nodes for them. To support that rewrite disk_devt to
look at the major and first_minor fields in the gendisk itself instead
of looking into the struct device.Signed-off-by: Christoph Hellwig
Reviewed-by: Johannes Thumshirn
Reviewed-by: Hannes Reinecke
Signed-off-by: Jens Axboe
26 Oct, 2017
1 commit
-
Darrick posted the following warning and Dave Chinner analyzed it:
> ======================================================
> WARNING: possible circular locking dependency detected
> 4.14.0-rc1-fixes #1 Tainted: G W
> ------------------------------------------------------
> loop0/31693 is trying to acquire lock:
> (&(&ip->i_mmaplock)->mr_lock){++++}, at: [] xfs_ilock+0x23c/0x330 [xfs]
>
> but now in release context of a crosslock acquired at the following:
> ((complete)&ret.event){+.+.}, at: [] submit_bio_wait+0x7f/0xb0
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 ((complete)&ret.event){+.+.}:
> lock_acquire+0xab/0x200
> wait_for_completion_io+0x4e/0x1a0
> submit_bio_wait+0x7f/0xb0
> blkdev_issue_zeroout+0x71/0xa0
> xfs_bmapi_convert_unwritten+0x11f/0x1d0 [xfs]
> xfs_bmapi_write+0x374/0x11f0 [xfs]
> xfs_iomap_write_direct+0x2ac/0x430 [xfs]
> xfs_file_iomap_begin+0x20d/0xd50 [xfs]
> iomap_apply+0x43/0xe0
> dax_iomap_rw+0x89/0xf0
> xfs_file_dax_write+0xcc/0x220 [xfs]
> xfs_file_write_iter+0xf0/0x130 [xfs]
> __vfs_write+0xd9/0x150
> vfs_write+0xc8/0x1c0
> SyS_write+0x45/0xa0
> entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> -> #1 (&xfs_nondir_ilock_class){++++}:
> lock_acquire+0xab/0x200
> down_write_nested+0x4a/0xb0
> xfs_ilock+0x263/0x330 [xfs]
> xfs_setattr_size+0x152/0x370 [xfs]
> xfs_vn_setattr+0x6b/0x90 [xfs]
> notify_change+0x27d/0x3f0
> do_truncate+0x5b/0x90
> path_openat+0x237/0xa90
> do_filp_open+0x8a/0xf0
> do_sys_open+0x11c/0x1f0
> entry_SYSCALL_64_fastpath+0x1f/0xbe
>
> -> #0 (&(&ip->i_mmaplock)->mr_lock){++++}:
> up_write+0x1c/0x40
> xfs_iunlock+0x1d0/0x310 [xfs]
> xfs_file_fallocate+0x8a/0x310 [xfs]
> loop_queue_work+0xb7/0x8d0
> kthread_worker_fn+0xb9/0x1f0
>
> Chain exists of:
> &(&ip->i_mmaplock)->mr_lock --> &xfs_nondir_ilock_class --> (complete)&ret.event
>
> Possible unsafe locking scenario by crosslock:
>
> CPU0 CPU1
> ---- ----
> lock(&xfs_nondir_ilock_class);
> lock((complete)&ret.event);
> lock(&(&ip->i_mmaplock)->mr_lock);
> unlock((complete)&ret.event);
>
> *** DEADLOCK ***The warning is a false positive, caused by the fact that all
wait_for_completion()s in submit_bio_wait() are waiting with the same
lock class.However, some bios have nothing to do with others, for example in the case
of loop devices, there's no direct connection between the bios of an upper
device and the bios of a lower device(=loop device).The safest way to assign different lock classes to different devices is
to do it for each gendisk. In other words, this patch assigns a
lockdep_map per gendisk and uses it when initializing completion in
submit_bio_wait().Analyzed-by: Dave Chinner
Reported-by: Darrick J. Wong
Signed-off-by: Byungchul Park
Reviewed-by: Jens Axboe
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-10-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar
