From 62d3c5439c534b0e6c653fc63e6d8c67be3a57b1 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 2 Mar 2012 10:51:00 +0100 Subject: 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 CC: Acked-by: Tejun Heo Acked-by: Rafael J. Wysocki Signed-off-by: Jens Axboe --- include/linux/workqueue.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index eb8b9f15f2e0..af155450cabb 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -289,12 +289,16 @@ enum { * * system_freezable_wq is equivalent to system_wq except that it's * freezable. + * + * system_nrt_freezable_wq is equivalent to system_nrt_wq except that + * it's freezable. */ extern struct workqueue_struct *system_wq; extern struct workqueue_struct *system_long_wq; extern struct workqueue_struct *system_nrt_wq; extern struct workqueue_struct *system_unbound_wq; extern struct workqueue_struct *system_freezable_wq; +extern struct workqueue_struct *system_nrt_freezable_wq; extern struct workqueue_struct * __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, -- cgit v1.2.3