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| author | Alan Stern <stern@rowland.harvard.edu> | 2012-03-02 10:51:00 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-03-02 10:51:00 +0100 |
| commit | 62d3c5439c534b0e6c653fc63e6d8c67be3a57b1 (patch) | |
| tree | d335d0e449ef2d61d52921e3f210cdd403bb025a /kernel | |
| parent | cecd353a02fb1405c8a72a324b26b5acf97e7411 (diff) | |
| download | lwn-62d3c5439c534b0e6c653fc63e6d8c67be3a57b1.tar.gz lwn-62d3c5439c534b0e6c653fc63e6d8c67be3a57b1.zip | |
Block: use a freezable workqueue for disk-event polling
This patch (as1519) fixes a bug in the block layer's disk-events
polling. The polling is done by a work routine queued on the
system_nrt_wq workqueue. Since that workqueue isn't freezable, the
polling continues even in the middle of a system sleep transition.
Obviously, polling a suspended drive for media changes and such isn't
a good thing to do; in the case of USB mass-storage devices it can
lead to real problems requiring device resets and even re-enumeration.
The patch fixes things by creating a new system-wide, non-reentrant,
freezable workqueue and using it for disk-events polling.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/workqueue.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index bec7b5b53e03..f2c5638bb5ab 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -253,11 +253,13 @@ struct workqueue_struct *system_long_wq __read_mostly; struct workqueue_struct *system_nrt_wq __read_mostly; struct workqueue_struct *system_unbound_wq __read_mostly; struct workqueue_struct *system_freezable_wq __read_mostly; +struct workqueue_struct *system_nrt_freezable_wq __read_mostly; EXPORT_SYMBOL_GPL(system_wq); EXPORT_SYMBOL_GPL(system_long_wq); EXPORT_SYMBOL_GPL(system_nrt_wq); EXPORT_SYMBOL_GPL(system_unbound_wq); EXPORT_SYMBOL_GPL(system_freezable_wq); +EXPORT_SYMBOL_GPL(system_nrt_freezable_wq); #define CREATE_TRACE_POINTS #include <trace/events/workqueue.h> @@ -3833,8 +3835,11 @@ static int __init init_workqueues(void) WQ_UNBOUND_MAX_ACTIVE); system_freezable_wq = alloc_workqueue("events_freezable", WQ_FREEZABLE, 0); + system_nrt_freezable_wq = alloc_workqueue("events_nrt_freezable", + WQ_NON_REENTRANT | WQ_FREEZABLE, 0); BUG_ON(!system_wq || !system_long_wq || !system_nrt_wq || - !system_unbound_wq || !system_freezable_wq); + !system_unbound_wq || !system_freezable_wq || + !system_nrt_freezable_wq); return 0; } early_initcall(init_workqueues); |