People reported that commit:
5680d8094f ("sched/clock: Provide better clock continuity")
broke "perf test tsc".
That commit added another offset to the reported clock value; so
take that into account when computing the provided offset values.
Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 5680d8094f ("sched/clock: Provide better clock continuity")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Paul reported a problems with clear_sched_clock_stable(). Since we run
all of __clear_sched_clock_stable() from workqueue context, there's a
preempt problem.
Solve it by only running the static_key_disable() from workqueue.
Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: fweisbec@gmail.com
Link: http://lkml.kernel.org/r/20170313124621.GA3328@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The wrong GPIO line was provided here.
Fixes: ef8d2ffedf ("ARM64: dts: meson-gxbb: add MMC support")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
This patch describes the GPIO lines usage on the Odroid-C2 board.
This is useful in the debugfs gpio file and using the cdev gpio API.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
This patch adds support for the P230 and Q200 ADC laddered button and
GPIO button.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Since AQC-100/107/108 chips supports hardware checksums for RX we should indicate this
via NETIF_F_RXCSUM flag.
v1->v2: 'Signed-off-by' tag added.
Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ECC bit positions that describe whether the ECC interrupt is for
Tx, Rx or descriptor memory and whether the it is a single correctable
or double detected error were defined in incorrectly (reversed order).
Fix the bit position definitions for these settings so that the proper
ECC handling is performed.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stephen Hemminger says:
====================
netvsc: bug fixes and cleanups
These fix NAPI issues and bugs found during testing of shutdown
testing.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix warning from unused set_complete variable. And rearrange code
to eliminate unnecessary goto's.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since there already is a special case goto for control messages (skb == NULL)
in netvsc_send, there is no need for later checks in same code path.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The channel inbound lock was not being used at all by the netvsc
device, but the spin_lock was helpful by providing necessary
barrier before waiting.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rather than a lock and variable, use a refcount_t to keep track
of the number of sub channels. Don't need to wait for subchannels
on device removal since wait was already done in device_add.
Also fix the error handling; don't wait forever in case of
an error on request to create sub channels.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is cleaner to use RCU protected pointer (nvdev_ctx->nvdev)
to indicate device is in removed state, rather than having a separate
boolean flag. By using the pointer the context can be checked
by static checkers and dynamic lockdep.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The netvsc driver has an internal structure (netvsc_device) which
is created when device is opened and released when device is closed.
And also opened/released when MTU or number of channels change.
Since this is referenced in the receive and transmit path, it is
safer to use RCU to protect/prevent use after free problems.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The default number of maximum channels should be limited to the
number of cpus available on the numa node of the primary channel.
This also makes sure maximum channels <= num_online_cpus
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If device is not up, then changing MTU (or number of channels)
should not re-enable the device.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using NAPI, the single stream performance declined signifcantly
because the poll routine was updating host after every burst
of packets. This excess signalling caused host throttling.
This fix restores the old behavior. Host is only signalled
after the ring has been emptied.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If there are no egress packets pending, then don't look for tx completions
in napi poll. Also, fix broken tx queue wakeup logic.
Signed-off-by: VSR Burru <veerasenareddy.burru@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add workqueue that is periodically run to try to allocate RX buffers in OOM
conditions in PF and VF.
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.
Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ethtool api {get|set}_settings is deprecated.
We move this driver to new api {get|set}_link_ksettings.
Signed-off-by: Philippe Reynes <tremyfr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Presumably if there is an "add" function, there is also a "del"
function. But it causes a static checker warning because it looks like
a common cut and paste bug.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
compile-testing fails when QCOM_SMD is a loadable module:
drivers/bluetooth/built-in.o: In function `btqcomsmd_send':
btqca.c:(.text+0xa8): undefined reference to `qcom_smd_send'
drivers/bluetooth/built-in.o: In function `btqcomsmd_probe':
btqca.c:(.text+0x3ec): undefined reference to `qcom_wcnss_open_channel'
btqca.c:(.text+0x46c): undefined reference to `qcom_smd_set_drvdata'
This clarifies the dependency to allow compile-testing only when
SMD is completely disabled, otherwise the dependency on QCOM_SMD
will make sure we can link against it.
Fixes: e27ee2b16b ("Bluetooth: btqcomsmd: Allow driver to build if COMPILE_TEST is enabled")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[bjorn: Restructure and clarify dependency to QCOM_WCNSS_CTRL]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The 'writes_pending' counter is used to determine when the
array is stable so that it can be marked in the superblock
as "Clean". Consequently it needs to be updated frequently
but only checked for zero occasionally. Recent changes to
raid5 cause the count to be updated even more often - once
per 4K rather than once per bio. This provided
justification for making the updates more efficient.
So we replace the atomic counter a percpu-refcount.
This can be incremented and decremented cheaply most of the
time, and can be switched to "atomic" mode when more
precise counting is needed. As it is possible for multiple
threads to want a precise count, we introduce a
"sync_checker" counter to count the number of threads
in "set_in_sync()", and only switch the refcount back
to percpu mode when that is zero.
We need to be careful about races between set_in_sync()
setting ->in_sync to 1, and md_write_start() setting it
to zero. md_write_start() holds the rcu_read_lock()
while checking if the refcount is in percpu mode. If
it is, then we know a switch to 'atomic' will not happen until
after we call rcu_read_unlock(), in which case set_in_sync()
will see the elevated count, and not set in_sync to 1.
If it is not in percpu mode, we take the mddev->lock to
ensure proper synchronization.
It is no longer possible to quickly check if the count is zero, which
we previously did to update a timer or to schedule the md_thread.
So now we do these every time we decrement that counter, but make
sure they are fast.
mod_timer() already optimizes the case where the timeout value doesn't
actually change. We leverage that further by always rounding off the
jiffies to the timeout value. This may delay the marking of 'clean'
slightly, but ensure we only perform atomic operation here when absolutely
needed.
md_wakeup_thread() current always calls wake_up(), even if
THREAD_WAKEUP is already set. That too can be optimised to avoid
calls to wake_up().
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
percpu_ref_switch_to_atomic_sync() schedules the switch to atomic mode, then
waits for it to complete.
Also export percpu_ref_switch_to_* so they can be used from modules.
This will be used in md/raid to count the number of pending write
requests to an array.
We occasionally need to check if the count is zero, but most often
we don't care.
We always want updates to the counter to be fast, as in some cases
we count every 4K page.
Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
If ->in_sync is being set just as md_write_start() is being called,
it is possible that set_in_sync() won't see the elevated
->writes_pending, and md_write_start() won't see the set ->in_sync.
To close this race, re-test ->writes_pending after setting ->in_sync,
and add memory barriers to ensure the increment of ->writes_pending
will be seen by the time of this second test, or the new ->in_sync
will be seen by md_write_start().
Add a spinlock to array_state_show() to ensure this temporary
instability is never visible from userspace.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Three separate places in md.c check if the number of active
writes is zero and, if so, sets mddev->in_sync.
There are a few differences, but there shouldn't be:
- it is always appropriate to notify the change in
sysfs_state, and there is no need to do this outside a
spin-locked region.
- we never need to check ->recovery_cp. The state of resync
is not relevant for whether there are any pending writes
or not (which is what ->in_sync reports).
So create set_in_sync() which does the correct tests and
makes the correct changes, and call this in all three
places.
Any behaviour changes here a minor and cosmetic.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This test on ->writes_pending cannot be safe as the counter
can be incremented at any moment and cannot be locked against.
Change it to test conf->active_stripes, which at least
can be locked against. More changes are still needed.
A future patch will change ->writes_pending, and testing it here will
be very inconvenient.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Change to use bio->__bi_remaining to count number of r1bio attached
to a bio.
See precious raid10 patch for more details.
Like the raid10.c patch, this fixes a bug as nr_queued and nr_pending
used to measure different things, but were being compared.
This patch fixes another bug in that nr_pending previously did not
could write-behind requests, so behind writes could continue while
resync was happening. How that nr_pending counts all r1_bio,
the resync cannot commence until the behind writes have completed.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
raid10 currently repurposes bi_phys_segments on each
incoming bio to count how many r10bio was used to encode the
request.
We need to know when the number of attached r10bio reaches
zero to:
1/ call bio_endio() when all IO on the bio is finished
2/ decrement ->nr_pending so that resync IO can proceed.
Now that the bio has its own __bi_remaining counter, that
can be used instead. We can call bio_inc_remaining to
increment the counter and call bio_endio() every time an
r10bio completes, rather than only when bi_phys_segments
reaches zero.
This addresses point 1, but not point 2. bio_endio()
doesn't (and cannot) report when the last r10bio has
finished, so a different approach is needed.
So: instead of counting bios in ->nr_pending, count r10bios.
i.e. every time we attach a bio, increment nr_pending.
Every time an r10bio completes, decrement nr_pending.
Normally we only increment nr_pending after first checking
that ->barrier is zero, or some other non-trivial tests and
possible waiting. When attaching multiple r10bios to a bio,
we only need the tests and the waiting once. After the
first increment, subsequent increments can happen
unconditionally as they are really all part of the one
request.
So introduce inc_pending() which can be used when we know
that nr_pending is already elevated.
Note that this fixes a bug. freeze_array() contains the line
atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
which implies that the units for ->nr_pending, ->nr_queued and extra
are the same.
->nr_queue and extra count r10_bios, but prior to this patch,
->nr_pending counted bios. If a bio ever resulted in multiple
r10_bios (due to bad blocks), freeze_array() would not work correctly.
Now it does.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
When raid1 or raid10 find they will need to allocate a new
r1bio/r10bio, in order to work around a known bad block, they
account for the allocation well before the allocation is
made. This separation makes the correctness less obvious
and requires comments.
The accounting needs to be a little before: before the first
rXbio is submitted, but that is all.
So move the accounting down to where it makes more sense.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Iyappan Subramanian says:
====================
drivers: net: xgene-v2: Add MDIO and ethtool support
This patch set,
- adds phy management and ethtool support
- fixes ethernet reset
- addresses review comments from previous patch set
v2: Address review comments from v1
- removed mdio_lock, since there is a top level lock in mdio_bus.c
v1:
- Initial version
====================
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixed review comments from the previous patch-set.
- changed return value check of platform_get_irq() to < 0
- replaced devm_request(free)_irq() calls by request(free)_irq() since
they are called from open() and close()
- changed sizeof(struct mystruct) to sizeof(*mystruct)
- reduced indentation on tx_timeout()
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixed port reset sequence by adding ECC init.
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Added phy management support by using phy abstraction layer APIs.
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit e8d7c33232.
Now that raid5 doesn't abuse bi_phys_segments any more, we no longer
need to impose these limits.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Turn the different ways of merging or issuing I/O into a series of if/else
statements instead of the current maze of gotos. Note that this means we
pin the CPU a little longer for some cases as the CTX put is moved to
common code at the end of the function.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Now that we have a nice direct issue heper this helps simplifying
the code a bit, and also gets rid of the old_rq variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Rename blk_mq_try_issue_directly to __blk_mq_try_issue_directly and add a
new wrapper that takes care of RCU / SRCU locking to avoid having
boileplate code in the caller which would get duplicated with new callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
They are mostly the same code anyway - this just one small conditional
for the plug case that is different for both variants.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
When a read request, which bypassed the cache, fails, we need to retry
it through the cache.
This involves attaching it to a sequence of stripe_heads, and it may not
be possible to get all the stripe_heads we need at once.
We do what we can, and record how far we got in ->bi_phys_segments so
we can pick up again later.
There is only ever one bio which may have a non-zero offset stored in
->bi_phys_segments, the one that is either active in the single thread
which calls retry_aligned_read(), or is in conf->retry_read_aligned
waiting for retry_aligned_read() to be called again.
So we only need to store one offset value. This can be in a local
variable passed between remove_bio_from_retry() and
retry_aligned_read(), or in the r5conf structure next to the
->retry_read_aligned pointer.
Storing it there allows the last usage of ->bi_phys_segments to be
removed from md/raid5.c.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
This flag was never used since it was introduced.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
md/raid5 needs to keep track of how many stripe_heads are processing a
bio so that it can delay calling bio_endio() until all stripe_heads
have completed. It currently uses 16 bits of ->bi_phys_segments for
this purpose.
16 bits is only enough for 256M requests, and it is possible for a
single bio to be larger than this, which causes problems. Also, the
bio struct contains a larger counter, __bi_remaining, which has a
purpose very similar to the purpose of our counter. So stop using
->bi_phys_segments, and instead use __bi_remaining.
This means we don't need to initialize the counter, as our caller
initializes it to '1'. It also means we can call bio_endio() directly
as it tests this counter internally.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
We currently gather bios that need to be returned into a bio_list
and call bio_endio() on them all together.
The original reason for this was to avoid making the calls while
holding a spinlock.
Locking has changed a lot since then, and that reason is no longer
valid.
So discard return_io() and various return_bi lists, and just call
bio_endio() directly as needed.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
If a device fails during a write, we must ensure the failure is
recorded in the metadata before the completion of the write is
acknowleged.
Commit c3cce6cda1 ("md/raid5: ensure device failure recorded before
write request returns.") added code for this, but it was
unnecessarily complicated. We already had similar functionality for
handling updates to the bad-block-list, thanks to Commit de393cdea6
("md: make it easier to wait for bad blocks to be acknowledged.")
So revert most of the former commit, and instead avoid collecting
completed writes if MD_CHANGE_PENDING is set. raid5d() will then flush
the metadata and retry the stripe_head.
As this change can leave a stripe_head ready for handling immediately
after handle_active_stripes() returns, we change raid5_do_work() to
pause when MD_CHANGE_PENDING is set, so that it doesn't spin.
We check MD_CHANGE_PENDING *after* analyse_stripe() as it could be set
asynchronously. After analyse_stripe(), we have collected stable data
about the state of devices, which will be used to make decisions.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
We use md_write_start() to increase the count of pending writes, and
md_write_end() to decrement the count. We currently count bios
submitted to md/raid5. Change it count stripe_heads that a WRITE bio
has been attached to.
So now, raid5_make_request() calls md_write_start() and then
md_write_end() to keep the count elevated during the setup of the
request.
add_stripe_bio() calls md_write_start() for each stripe_head, and the
completion routines always call md_write_end(), instead of only
calling it when raid5_dec_bi_active_stripes() returns 0.
make_discard_request also calls md_write_start/end().
The parallel between md_write_{start,end} and use of bi_phys_segments
can be seen in that:
Whenever we set bi_phys_segments to 1, we now call md_write_start.
Whenever we increment it on non-read requests with
raid5_inc_bi_active_stripes(), we now call md_write_start().
Whenever we decrement bi_phys_segments on non-read requsts with
raid5_dec_bi_active_stripes(), we now call md_write_end().
This reduces our dependence on keeping a per-bio count of active
stripes in bi_phys_segments.
md_write_inc() is added which parallels md_write_start(), but requires
that a write has already been started, and is certain never to sleep.
This can be used inside a spinlocked region when adding to a write
request.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
When device open races with device shutdown, we can get the following
oops in scsi_disk_get():
[11863.044351] general protection fault: 0000 [#1] SMP
[11863.045561] Modules linked in: scsi_debug xfs libcrc32c netconsole btrfs raid6_pq zlib_deflate lzo_compress xor [last unloaded: loop]
[11863.047853] CPU: 3 PID: 13042 Comm: hald-probe-stor Tainted: G W 4.10.0-rc2-xen+ #35
[11863.048030] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[11863.048030] task: ffff88007f438200 task.stack: ffffc90000fd0000
[11863.048030] RIP: 0010:scsi_disk_get+0x43/0x70
[11863.048030] RSP: 0018:ffffc90000fd3a08 EFLAGS: 00010202
[11863.048030] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88007f56d000 RCX: 0000000000000000
[11863.048030] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff81a8d880
[11863.048030] RBP: ffffc90000fd3a18 R08: 0000000000000000 R09: 0000000000000001
[11863.059217] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffa
[11863.059217] R13: ffff880078872800 R14: ffff880070915540 R15: 000000000000001d
[11863.059217] FS: 00007f2611f71800(0000) GS:ffff88007f0c0000(0000) knlGS:0000000000000000
[11863.059217] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[11863.059217] CR2: 000000000060e048 CR3: 00000000778d4000 CR4: 00000000000006e0
[11863.059217] Call Trace:
[11863.059217] ? disk_get_part+0x22/0x1f0
[11863.059217] sd_open+0x39/0x130
[11863.059217] __blkdev_get+0x69/0x430
[11863.059217] ? bd_acquire+0x7f/0xc0
[11863.059217] ? bd_acquire+0x96/0xc0
[11863.059217] ? blkdev_get+0x350/0x350
[11863.059217] blkdev_get+0x126/0x350
[11863.059217] ? _raw_spin_unlock+0x2b/0x40
[11863.059217] ? bd_acquire+0x7f/0xc0
[11863.059217] ? blkdev_get+0x350/0x350
[11863.059217] blkdev_open+0x65/0x80
...
As you can see RAX value is already poisoned showing that gendisk we got
is already freed. The problem is that get_gendisk() looks up device
number in ext_devt_idr and then does get_disk() which does kobject_get()
on the disks kobject. However the disk gets removed from ext_devt_idr
only in disk_release() (through blk_free_devt()) at which moment it has
already 0 refcount and is already on its way to be freed. Indeed we've
got a warning from kobject_get() about 0 refcount shortly before the
oops.
We fix the problem by using kobject_get_unless_zero() in get_disk() so
that get_disk() cannot get reference on a disk that is already being
freed.
Tested-by: Lekshmi Pillai <lekshmicpillai@in.ibm.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Make the function available for outside use and fortify it against NULL
kobject.
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
