kernel/linux.git/block/genhd.c, branch v3.8.8

block: fix synchronization and limit check in blk_alloc_devt()

2013-03-03T22:03:35+00:00

commit ce23bba842aee98092225d9576dba47c82352521 upstream. idr allocation in blk_alloc_devt() wasn't synchronized against lookup and removal, and its limit check was off by one - 1 << MINORBITS is the number of minors allowed, not the maximum allowed minor. Add locking and rename MAX_EXT_DEVT to NR_EXT_DEVT and fix limit checking. Signed-off-by: Tejun Heo Acked-by: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

block: fix ext_devt_idr handling

2013-03-03T22:03:35+00:00

commit 7b74e912785a11572da43292786ed07ada7e3e0c upstream. While adding and removing a lot of disks disks and partitions this sometimes shows up: WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted) Hardware name: sysfs: cannot create duplicate filename '/dev/block/259:751' Modules linked in: raid1 autofs4 bnx2fc cnic uio fcoe libfcoe libfc 8021q scsi_transport_fc scsi_tgt garp stp llc sunrpc cpufreq_ondemand powernow_k8 freq_table mperf ipv6 dm_mirror dm_region_hash dm_log power_meter microcode dcdbas serio_raw amd64_edac_mod edac_core edac_mce_amd i2c_piix4 i2c_core k10temp bnx2 sg ixgbe dca mdio ext4 mbcache jbd2 dm_round_robin sr_mod cdrom sd_mod crc_t10dif ata_generic pata_acpi pata_atiixp ahci mptsas mptscsih mptbase scsi_transport_sas dm_multipath dm_mod [last unloaded: scsi_wait_scan] Pid: 44103, comm: async/16 Not tainted 2.6.32-195.el6.x86_64 #1 Call Trace: warn_slowpath_common+0x87/0xc0 warn_slowpath_fmt+0x46/0x50 sysfs_add_one+0xc9/0x130 sysfs_do_create_link+0x12b/0x170 sysfs_create_link+0x13/0x20 device_add+0x317/0x650 idr_get_new+0x13/0x50 add_partition+0x21c/0x390 rescan_partitions+0x32b/0x470 sd_open+0x81/0x1f0 [sd_mod] __blkdev_get+0x1b6/0x3c0 blkdev_get+0x10/0x20 register_disk+0x155/0x170 add_disk+0xa6/0x160 sd_probe_async+0x13b/0x210 [sd_mod] add_wait_queue+0x46/0x60 async_thread+0x102/0x250 default_wake_function+0x0/0x20 async_thread+0x0/0x250 kthread+0x96/0xa0 child_rip+0xa/0x20 kthread+0x0/0xa0 child_rip+0x0/0x20 This most likely happens because dev_t is freed while the number is still used and idr_get_new() is not protected on every use. The fix adds a mutex where it wasn't before and moves the dev_t free function so it is called after device del. Signed-off-by: Tomas Henzl Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

block: prevent race/cleanup

2012-12-19T19:36:10+00:00

Remove a race condition which causes a warning in disk_clear_events. This is a race between disk_clear_events() and disk_flush_events(). ev->clearing will be altered by disk_flush_events() even though we are blocking event checking through disk_flush_events(). If this happens after ev->clearing was cleared for disk_clear_events(), this can cause the WARN_ON_ONCE() in that function to be triggered. This change also has disk_clear_events() not go through a workqueue. Since we have to wait for the work to complete, we should just call the function directly. Also, since this work cannot be put on a freezable workqueue, it will have to contend with increased demand, so calling the function directly avoids this. [akpm@linux-foundation.org: fix spello in comment] Signed-off-by: Derek Basehore Cc: Mandeep Singh Baines Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe

block: remove deadlock in disk_clear_events

2012-12-19T19:36:05+00:00

In disk_clear_events, do not put work on system_nrt_freezable_wq. Instead, put it on system_nrt_wq. There is a race between probing a usb and suspending the device. Since probing a usb calls disk_clear_events, which puts work on a frozen workqueue, probing cannot finish after the workqueue is frozen. However, suspending cannot finish until the usb probe is finished, so we get a deadlock, causing the system to reboot. The way to reproduce this bug is to wake up from suspend with a usb storage device plugged in, or plugging in a usb storage device right before suspend. The window of time is on the order of time it takes to probe the usb device. As long as the workqueues are frozen before the call to add_disk within sd_probe_async finishes, there will be a deadlock (which calls blkdev_get, sd_open, check_disk_change, then disk_clear_events). This is not difficult to reproduce after figuring out the timings. [akpm@linux-foundation.org: fix up comment] Signed-off-by: Derek Basehore Reviewed-by: Mandeep Singh Baines Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe

Merge branch 'for-3.8/drivers' of git://git.kernel.dk/linux-block

2012-12-17T21:39:11+00:00

Pull block driver update from Jens Axboe: "Now that the core bits are in, here are the driver bits for 3.8. The branch contains: - A huge pile of drbd bits that were dumped from the 3.7 merge window. Following that, it was both made perfectly clear that there is going to be no more over-the-wall pulls and how the situation on individual pulls can be improved. - A few cleanups from Akinobu Mita for drbd and cciss. - Queue improvement for loop from Lukas. This grew into adding a generic interface for waiting/checking an even with a specific lock, allowing this to be pulled out of md and now loop and drbd is also using it. - A few fixes for xen back/front block driver from Roger Pau Monne. - Partition improvements from Stephen Warren, allowing partiion UUID to be used as an identifier." * 'for-3.8/drivers' of git://git.kernel.dk/linux-block: (609 commits) drbd: update Kconfig to match current dependencies drbd: Fix drbdsetup wait-connect, wait-sync etc... commands drbd: close race between drbd_set_role and drbd_connect drbd: respect no-md-barriers setting also when changed online via disk-options drbd: Remove obsolete check drbd: fixup after wait_even_lock_irq() addition to generic code loop: Limit the number of requests in the bio list wait: add wait_event_lock_irq() interface xen-blkfront: free allocated page xen-blkback: move free persistent grants code block: partition: msdos: provide UUIDs for partitions init: reduce PARTUUID min length to 1 from 36 block: store partition_meta_info.uuid as a string cciss: use check_signature() cciss: cleanup bitops usage drbd: use copy_highpage drbd: if the replication link breaks during handshake, keep retrying drbd: check return of kmalloc in receive_uuids drbd: Broadcast sync progress no more often than once per second drbd: don't try to clear bits once the disk has failed ...

block: store partition_meta_info.uuid as a string

2012-11-23T13:28:53+00:00

This will allow other types of UUID to be stored here, aside from true UUIDs. This also simplifies code that uses this field, since it's usually constructed from a, used as a, or compared to other, strings. Note: A simplistic approach here would be to set uuid_str[36]=0 whenever a /PARTNROFF option was found to be present. However, this modifies the input string, and causes subsequent calls to devt_from_partuuid() not to see the /PARTNROFF option, which causes different results. In order to avoid misleading future maintainers, this parameter is marked const. Signed-off-by: Stephen Warren Cc: Tejun Heo Cc: Will Drewry Cc: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe

block: use NUMA_NO_NODE instead of -1

2012-11-10T09:41:13+00:00

Signed-off-by: Ezequiel Garcia Modified by me to cover blk_init_queue() as well. Signed-off-by: Jens Axboe

Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2012-10-02T16:54:49+00:00

Pull workqueue changes from Tejun Heo: "This is workqueue updates for v3.7-rc1. A lot of activities this round including considerable API and behavior cleanups. * delayed_work combines a timer and a work item. The handling of the timer part has always been a bit clunky leading to confusing cancelation API with weird corner-case behaviors. delayed_work is updated to use new IRQ safe timer and cancelation now works as expected. * Another deficiency of delayed_work was lack of the counterpart of mod_timer() which led to cancel+queue combinations or open-coded timer+work usages. mod_delayed_work[_on]() are added. These two delayed_work changes make delayed_work provide interface and behave like timer which is executed with process context. * A work item could be executed concurrently on multiple CPUs, which is rather unintuitive and made flush_work() behavior confusing and half-broken under certain circumstances. This problem doesn't exist for non-reentrant workqueues. While non-reentrancy check isn't free, the overhead is incurred only when a work item bounces across different CPUs and even in simulated pathological scenario the overhead isn't too high. All workqueues are made non-reentrant. This removes the distinction between flush_[delayed_]work() and flush_[delayed_]_work_sync(). The former is now as strong as the latter and the specified work item is guaranteed to have finished execution of any previous queueing on return. * In addition to the various bug fixes, Lai redid and simplified CPU hotplug handling significantly. * Joonsoo introduced system_highpri_wq and used it during CPU hotplug. There are two merge commits - one to pull in IRQ safe timer from tip/timers/core and the other to pull in CPU hotplug fixes from wq/for-3.6-fixes as Lai's hotplug restructuring depended on them." Fixed a number of trivial conflicts, but the more interesting conflicts were silent ones where the deprecated interfaces had been used by new code in the merge window, and thus didn't cause any real data conflicts. Tejun pointed out a few of them, I fixed a couple more. * 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits) workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending() workqueue: use cwq_set_max_active() helper for workqueue_set_max_active() workqueue: introduce cwq_set_max_active() helper for thaw_workqueues() workqueue: remove @delayed from cwq_dec_nr_in_flight() workqueue: fix possible stall on try_to_grab_pending() of a delayed work item workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback() workqueue: use __cpuinit instead of __devinit for cpu callbacks workqueue: rename manager_mutex to assoc_mutex workqueue: WORKER_REBIND is no longer necessary for idle rebinding workqueue: WORKER_REBIND is no longer necessary for busy rebinding workqueue: reimplement idle worker rebinding workqueue: deprecate __cancel_delayed_work() workqueue: reimplement cancel_delayed_work() using try_to_grab_pending() workqueue: use mod_delayed_work() instead of __cancel + queue workqueue: use irqsafe timer for delayed_work workqueue: clean up delayed_work initializers and add missing one workqueue: make deferrable delayed_work initializer names consistent workqueue: cosmetic whitespace updates for macro definitions workqueue: deprecate system_nrt[_freezable]_wq workqueue: deprecate flush[_delayed]_work_sync() ...

workqueue: deprecate system_nrt[_freezable]_wq

2012-08-20T21:51:24+00:00

system_nrt[_freezable]_wq are now spurious. Mark them deprecated and convert all users to system[_freezable]_wq. If you're cc'd and wondering what's going on: Now all workqueues are non-reentrant, so there's no reason to use system_nrt[_freezable]_wq. Please use system[_freezable]_wq instead. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo Acked-By: Lai Jiangshan Cc: Jens Axboe Cc: David Airlie Cc: Jiri Kosina Cc: "David S. Miller" Cc: Rusty Russell Cc: "Paul E. McKenney" Cc: David Howells

workqueue: use mod_delayed_work() instead of cancel + queue

2012-08-13T23:27:37+00:00

Convert delayed_work users doing cancel_delayed_work() followed by queue_delayed_work() to mod_delayed_work(). Most conversions are straight-forward. Ones worth mentioning are, * drivers/edac/edac_mc.c: edac_mc_workq_setup() converted to always use mod_delayed_work() and cancel loop in edac_mc_reset_delay_period() is dropped. * drivers/platform/x86/thinkpad_acpi.c: No need to remember whether watchdog is active or not. @fan_watchdog_active and related code dropped. * drivers/power/charger-manager.c: Seemingly a lot of delayed_work_pending() abuse going on here. [delayed_]work_pending() are unsynchronized and racy when used like this. I converted one instance in fullbatt_handler(). Please conver the rest so that it invokes workqueue APIs for the intended target state rather than trying to game work item pending state transitions. e.g. if timer should be modified - call mod_delayed_work(), canceled - call cancel_delayed_work[_sync](). * drivers/thermal/thermal_sys.c: thermal_zone_device_set_polling() simplified. Note that round_jiffies() calls in this function are meaningless. round_jiffies() work on absolute jiffies not delta delay used by delayed_work. v2: Tomi pointed out that __cancel_delayed_work() users can't be safely converted to mod_delayed_work(). They could be calling it from irq context and if that happens while delayed_work_timer_fn() is running, it could deadlock. __cancel_delayed_work() users are dropped. Signed-off-by: Tejun Heo Acked-by: Henrique de Moraes Holschuh Acked-by: Dmitry Torokhov Acked-by: Anton Vorontsov Acked-by: David Howells Cc: Tomi Valkeinen Cc: Jens Axboe Cc: Jiri Kosina Cc: Doug Thompson Cc: David Airlie Cc: Roland Dreier Cc: "John W. Linville" Cc: Zhang Rui Cc: Len Brown Cc: "J. Bruce Fields" Cc: Johannes Berg