aboutsummaryrefslogtreecommitdiff
AgeCommit message (Collapse)Author
2009-10-28drbd: fix in_flight rw indexingJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28aio: implement request batchingJeff Moyer
Hi, Some workloads issue batches of small I/O, and the performance is poor due to the call to blk_run_address_space for every single iocb. Nathan Roberts pointed this out, and suggested that by deferring this call until all I/Os in the iocb array are submitted to the block layer, we can realize some impressive performance gains (up to 30% for sequential 4k reads in batches of 16). Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28block: get rid of the WRITE_ODIRECT flagJeff Moyer
Hi, The WRITE_ODIRECT flag is only used in one place, and that code path happens to also call blk_run_address_space. The introduction of this flag, then, could result in the device being unplugged twice for every I/O. Further, with the batching changes in the next patch, we don't want an O_DIRECT write to imply a queue unplug. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-27cfq-iosched: improve hw_tag detectionShaohua Li
If active queue hasn't enough requests and idle window opens, cfq will not dispatch sufficient requests to hardware. In such situation, current code will zero hw_tag. But this is because cfq doesn't dispatch enough requests instead of hardware queue doesn't work. Don't zero hw_tag in such case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26cfq: break apart merged cfqqs if they stop cooperatingJeff Moyer
cfq_queues are merged if they are issuing requests within the mean seek distance of one another. This patch detects when the coopearting stops and breaks the queues back up. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26cfq: change the meaning of the cfqq_coop flagJeff Moyer
The flag used to indicate that a cfqq was allowed to jump ahead in the scheduling order due to submitting a request close to the queue that just executed. Since closely cooperating queues are now merged, the flag holds little meaning. Change it to indicate that multiple queues were merged. This will later be used to allow the breaking up of merged queues when they are no longer cooperating. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26cfq: merge cooperating cfq_queuesJeff Moyer
When cooperating cfq_queues are detected currently, they are allowed to skip ahead in the scheduling order. It is much more efficient to automatically share the cfq_queue data structure between cooperating processes. Performance of the read-test2 benchmark (which is written to emulate the dump(8) utility) went from 12MB/s to 90MB/s on my SATA disk. NFS servers with multiple nfsd threads also saw performance increases. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26cfq: calculate the seek_mean per cfq_queue not per cfq_io_contextJeff Moyer
async cfq_queue's are already shared between processes within the same priority, and forthcoming patches will change the mapping of cic to sync cfq_queue from 1:1 to 1:N. So, calculate the seekiness of a process based on the cfq_queue instead of the cfq_io_context. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-13Merge branch 'for-linus' into for-2.6.33Jens Axboe
2009-10-13cciss: Add cciss_allow_hpsa module parameterStephen M. Cameron
Add cciss_allow_hpsa module parameter. This parameter causes the cciss driver to ignore any Smart Array devices known to be supported by the hpsa driver. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-13cciss: Fix multiple calls to pci_release_regionsStephen M. Cameron
Fix multiple calls to pci_release_regions. If cciss_pci_init fails, it already does any necessary call to pci_release_regions, so this does not need to be done again in cciss_init_one in that case. Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-12blk-settings: fix function parameter kernel-doc notationRandy Dunlap
Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors(). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09writeback: kill space in debugfs item nameWu Fengguang
The space is not script friendly, kill it. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09writeback: account IO throttling wait as iowaitWu Fengguang
It makes sense to do IOWAIT when someone is blocked due to IO throttle, as suggested by Kame and Peter. There is an old comment for not doing IOWAIT on throttle, however it has been mismatching the code for a long time. If we stop accounting IOWAIT for 2.6.32, it could be an undesirable behavior change. So restore the io_schedule. CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09elv_iosched_store(): fix strstrip() misuseKOSAKI Motohiro
elv_iosched_store() ignore the return value of strstrip(). It makes small inconsistent behavior. This patch fixes it. <before> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler bash: echo: write error: Invalid argument <after> ==================================== # cd /sys/block/{blockdev}/queue case1: # echo "anticipatory" > scheduler # cat scheduler noop [anticipatory] deadline cfq case2: # echo "anticipatory " > scheduler # cat scheduler noop [anticipatory] deadline cfq case3: # echo " anticipatory" > scheduler noop [anticipatory] deadline cfq Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-08cfq-iosched: avoid probable slice overrun when idlingCorrado Zoccolo
If the average think time is larger than the remaining time slice for any given queue, don't allow it to idle. A succesful idle also means that we need to dispatch and complete a request, so if we don't even have time left for the idle process, we would overrun the slice in any case. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-07cfq-iosched: apply bool value where we return 0/1Jens Axboe
Saves 16 bytes of text, woohoo. But the more important point is that it makes the code more readable when returning bool for 0/1 cases. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-07cfq-iosched: fix think time allowed for seekersCorrado Zoccolo
CFQ enables idle only for processes that think less than the allowed idle time. Since idle time is lower for seeky queues, we should use the correct value in the comparison. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-07drbd: needs __ratelimit()Randy Dunlap
drbd_int.h uses __ratelimit(), so it needs to #include ratelimit.h: drivers/block/drbd/drbd_int.h:1765: error: implicit declaration of function '__ratelimit' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: drbd-dev@lists.linbit.com Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06cfq-iosched: fix the slice residual signJens Axboe
We should subtract the slice residual from the rb tree key, since a negative residual count indicates that the cfqq overran its slice the last time. Hence we want to add the overrun time, to position it a bit further away in the service tree. Reported-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06cfq-iosched: abstract out the 'may this cfqq dispatch' logicJens Axboe
Makes the whole thing easier to read, cfq_dispatch_requests() was a bit messy before. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06block: use proper BLK_RW_ASYNC in blk_queue_start_tag()Jens Axboe
Makes it easier to read than the 0. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06block: Seperate read and write statistics of in_flight requests v2Nikanth Karthikesan
Commit a9327cac440be4d8333bba975cbbf76045096275 added seperate read and write statistics of in_flight requests. And exported the number of read and write requests in progress seperately through sysfs. But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange output from "iostat -kx 2". Global values for service time and utilization were garbage. For interval values, utilization was always 100%, and service time is higher than normal. So this was reverted by commit 0f78ab9899e9d6acb09d5465def618704255963b The problem was in part_round_stats_single(), I missed the following: if (now == part->stamp) return; - if (part->in_flight) { + if (part_in_flight(part)) { __part_stat_add(cpu, part, time_in_queue, part_in_flight(part) * (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); With this chunk included, the reported regression gets fixed. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> -- Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06drbd: Work on permission enforcementPhilipp Reisner
Now we have the capabilities of the sending process available, use them to enforce CAP_SYS_ADMIN. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05block: get rid of kblock_schedule_delayed_work()Jens Axboe
It was briefly introduced to allow CFQ to to delayed scheduling, but we ended up removing that feature again. So lets kill the function and export, and just switch CFQ back to the normal work schedule since it is now passing in a '0' delay from all call sites. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05cfq-iosched: fix possible problem with jiffies wraparoundCorrado Zoccolo
The RR service tree is indexed by a key that is relative to current jiffies. This can cause problems on jiffies wraparound. The patch fixes it using time_before comparison, and changing the add_front path to use a relative number, too. Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05cfq-iosched: fix issue with rq-rq merging and fifo list orderingJens Axboe
cfq uses rq->start_time as the fifo indicator, but that field may get modified prior to cfq doing it's fifo list adjustment when a request gets merged with another request. This can cause the fifo list to become unordered. Reported-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05drbd: fixup for reverted dual in_flight patchJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05Merge branch 'master' into for-2.6.33Jens Axboe
2009-10-04Linux 2.6.32-rc3Linus Torvalds
I'm skipping -rc2 because the -rc1 Makefile mistakenly said -rc2, so in order to avoid confusion, I'm jumping from -rc1 to -rc3. That way, when 'uname' (or an oops report) says 2.6.32-rc2, there's no confusion about whether people perhaps meant -rc1 or -rc2.
2009-10-04headers: remove sched.h from poll.hAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-04Merge branch 'acpi-pad' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 * 'acpi-pad' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: acpi_pad: build only on X86 ACPI: create Processor Aggregator Device driver Fixup trivial conflicts in MAINTAINERS file.
2009-10-04Merge branch 'sfi-release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-sfi-2.6 * 'sfi-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-sfi-2.6: SFI: remove __init from sfi_verify_table SFI: fix section mismatch warnings in sfi_core.c
2009-10-04Merge branch 'release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: ACPI: EC: Don't parse DSDT for EC early init on Compal ACPI: EC: Rewrite DMI checks ACPI: dock: fix "sibiling" typo ACPI: kill overly verbose "throttling states" log messages ACPI: Fix bound checks for copy_from_user in the acpi /proc code ACPI: fix bus scanning memory leaks ACPI: EC: Restart command even if no interrupts from EC sony-laptop: Don't unregister the SPIC driver if it wasn't registered sony-laptop: remove _INI call at init time sony-laptop: SPIC unset IRQF_SHARED, set IRQF_DISABLED sony-laptop: remove device_ctrl and the SPIC mini drivers
2009-10-04Merge branch 'i2c-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging * 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging: macintosh: Don't assume i2c device probing always succeeds i2c: Hide probe errors caused by ACPI resource conflicts i2c: Minor documentation update mfd: AB3100 drop unused module parameters Staging: IIO: tsl2561: Drop unused module parameters leds: leds-pca9532 - Drop unused module parameters ltc4215/ltc4245: Discard obsolete detect methods ds2482: Discard obsolete detect method max6875: Discard obsolete detect method i2c: Move misc devices documentation
2009-10-04macintosh: Don't assume i2c device probing always succeedsJean Delvare
If i2c device probing fails, then there is no driver to dereference after calling i2c_new_device(). Stop assuming that probing will always succeed, to avoid NULL pointer dereferences. We have an easier access to the driver anyway. Signed-off-by: Jean Delvare <khali@linux-fr.org> Tested-by: Tim Shepard <shep@alum.mit.edu> Cc: Colin Leroy <colin@colino.net>
2009-10-04i2c: Hide probe errors caused by ACPI resource conflictsJean Delvare
When an ACPI resource conflict is detected, error messages are already printed by ACPI. There's no point in causing the driver core to print more error messages, so return one of the error codes for which no message is printed. This fixes bug #14293: http://bugzilla.kernel.org/show_bug.cgi?id=14293 Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-10-04i2c: Minor documentation updateJean Delvare
The sysfs path to i2c adapters has changed recently, update the documentation to reflect that change. Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-10-04mfd: AB3100 drop unused module parametersJean Delvare
The I2C_CLIENT_INSMOD_1 macro is only useful for i2c drivers which implement device detection. The ab3100 driver doesn't, so there is no point in calling it. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Cc: Samuel Ortiz <sameo@linux.intel.com>
2009-10-04Staging: IIO: tsl2561: Drop unused module parametersJean Delvare
The I2C_CLIENT_INSMOD macro is only useful for i2c drivers which implement device detection. The tsl2561 driver doesn't, so there is no point in calling it. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Jonathan Cameron <jic23@cam.ac.uk>
2009-10-04leds: leds-pca9532 - Drop unused module parametersJean Delvare
The I2C_CLIENT_INSMOD_1 macro is only useful for i2c drivers which implement device detection. The leds-pca9532 driver doesn't, so there is no point in calling it. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Riku Voipio <riku.voipio@iki.fi>
2009-10-04ltc4215/ltc4245: Discard obsolete detect methodsJean Delvare
There is no point in implementing a detect callback for the LTC4215 and LTC4245, as these devices can't be detected. It was there solely to handle "force" module parameters to instantiate devices, but now we have a better sysfs interface that can do the same. So we can get rid of the ugly module parameters and the detect callbacks. This shrinks the binary module sizes by 36% and 46%, respectively. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Ira W. Snyder <iws@ovro.caltech.edu>
2009-10-04ds2482: Discard obsolete detect methodJean Delvare
There is no point in implementing a detect callback for the DS2482, as this device can't be detected. It was there solely to handle "force" module parameters to instantiate devices, but now we have a better sysfs interface that can do the same. So we can get rid of the ugly module parameters and the detect callback. This shrinks the binary module size by 21%. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Ben Gardner <gardner.ben@gmail.com>
2009-10-04max6875: Discard obsolete detect methodJean Delvare
There is no point in implementing a detect callback for the MAX6875, as this device can't be detected. It was there solely to handle "force" module parameters to instantiate devices, but now we have a better sysfs interface that can do the same. So we can get rid of the ugly module parameters and the detect callback. This basically divides the binary module size by 2. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Ben Gardner <gardner.ben@gmail.com>
2009-10-04i2c: Move misc devices documentationJean Delvare
Some times ago the eeprom and max6875 drivers moved to drivers/misc/eeprom, but their documentation did not follow. It's finally time to get rid of Documentation/i2c/chips. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Ben Gardner <gardner.ben@gmail.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de>
2009-10-04Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (41 commits) Revert "Seperate read and write statistics of in_flight requests" cfq-iosched: don't delay async queue if it hasn't dispatched at all block: Topology ioctls cfq-iosched: use assigned slice sync value, not default cfq-iosched: rename 'desktop' sysfs entry to 'low_latency' cfq-iosched: implement slower async initiate and queue ramp up cfq-iosched: delay async IO dispatch, if sync IO was just done cfq-iosched: add a knob for desktop interactiveness Add a tracepoint for block request remapping block: allow large discard requests block: use normal I/O path for discard requests swapfile: avoid NULL pointer dereference in swapon when s_bdev is NULL fs/bio.c: move EXPORT* macros to line after function Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs cciss: fix build when !PROC_FS block: Do not clamp max_hw_sectors for stacking devices block: Set max_sectors correctly for stacking devices cciss: cciss_host_attr_groups should be const cciss: Dynamically allocate the drive_info_struct for each logical drive. cciss: Add usage_count attribute to each logical drive in /sys ...
2009-10-04Revert "Seperate read and write statistics of in_flight requests"Jens Axboe
This reverts commit a9327cac440be4d8333bba975cbbf76045096275. Corrado Zoccolo <czoccolo@gmail.com> reports: "with 2.6.32-rc1 I started getting the following strange output from "iostat -kx 2": Linux 2.6.31bisect (et2) 04/10/2009 _i686_ (2 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 10,70 0,00 3,16 15,75 0,00 70,38 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 18,22 0,00 0,67 0,01 14,77 0,02 43,94 0,01 10,53 39043915,03 2629219,87 sdb 60,89 9,68 50,79 3,04 1724,43 50,52 65,95 0,70 13,06 488437,47 2629219,87 avg-cpu: %user %nice %system %iowait %steal %idle 2,72 0,00 0,74 0,00 0,00 96,53 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 6,68 0,00 0,99 0,00 0,00 92,33 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 avg-cpu: %user %nice %system %iowait %steal %idle 4,40 0,00 0,73 1,47 0,00 93,40 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 100,00 sdb 0,00 4,00 0,00 3,00 0,00 28,00 18,67 0,06 19,50 333,33 100,00 Global values for service time and utilization are garbage. For interval values, utilization is always 100%, and service time is higher than normal. I bisected it down to: [a9327cac440be4d8333bba975cbbf76045096275] Seperate read and write statistics of in_flight requests and verified that reverting just that commit indeed solves the issue on 2.6.32-rc1." So until this is debugged, revert the bad commit. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-04cfq-iosched: don't delay async queue if it hasn't dispatched at allJens Axboe
We cannot delay for the first dispatch of the async queue if it hasn't dispatched at all, since that could present a local user DoS attack vector using an app that just did slow timed sync reads while filling memory. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03Merge branch 'for-linus' of git://www.linux-m32r.org/git/takata/linux-2.6_devLinus Torvalds
* 'for-linus' of git://www.linux-m32r.org/git/takata/linux-2.6_dev: m32r: Fix IPI function calls for SMP m32r: Fix set_memory() for DISCONTIGMEM m32r: add rtc_lock variable m32r: define ioread* and iowrite* macros m32r: export delay loop symbols m32r: fix tme_handler
2009-10-03tty: Avoid dropping ldisc_mutex over hangup tty re-initializationLinus Torvalds
A couple of people have hit the WARN_ON() in drivers/char/tty_io.c, tty_open() that is unhappy about seeing the tty line discipline go away during the tty hangup. See for example http://bugzilla.kernel.org/show_bug.cgi?id=14255 and the reason is that we do the tty_ldisc_halt() outside the ldisc_mutex in order to be able to flush the scheduled work without a deadlock with vhangup_work. However, it turns out that we can solve this particular case by - using "cancel_delayed_work_sync()" in tty_ldisc_halt(), which waits for just the particular work, rather than synchronizing with any random outstanding pending work. This won't deadlock, since the buf.work we synchronize with doesn't care about the ldisc_mutex, it just flushes the tty ldisc buffers. - realize that for this particular case, we don't need to wait for any hangup work, because we are inside the hangup codepaths ourselves. so as a result we can just drop the flush_scheduled_work() entirely, and then move the tty_ldisc_halt() call to inside the mutex. That way we never expose the partially torn down ldisc state to tty_open(), and hold the ldisc_mutex over the whole sequence. Reported-by: Ingo Molnar <mingo@elte.hu> Reported-by: Heinz Diehl <htd@fancy-poultry.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>