xen/pciback: Use mutexes when working with Xenbus state transitions.
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Fri, 16 Sep 2011 18:43:14 +0000 (14:43 -0400)
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Wed, 21 Sep 2011 22:18:16 +0000 (18:18 -0400)
commitb1766b62890e3bba1a778a20ef8bf9348d6096c2
tree88655f8ba5d96d8086358c5ebd76680ef1f1ea08
parent402c5e15b44070461dcc2f41536c16d0cfbca9c3
xen/pciback: Use mutexes when working with Xenbus state transitions.

The caller that orchestrates the state changes is xenwatch_thread
and it takes a mutex. In our processing of Xenbus states we can take
the luxery of going to sleep on a mutex, so lets do that and
also fix this bug:

BUG: sleeping function called from invalid context at /linux/kernel/mutex.c:271
in_atomic(): 1, irqs_disabled(): 0, pid: 32, name: xenwatch
2 locks held by xenwatch/32:
 #0:  (xenwatch_mutex){......}, at: [<ffffffff813856ab>] xenwatch_thread+0x4b/0x180
 #1:  (&(&pdev->dev_lock)->rlock){......}, at: [<ffffffff8138f05b>] xen_pcibk_disconnect+0x1b/0x80
Pid: 32, comm: xenwatch Not tainted 3.1.0-rc6-00015-g3ce340d #2
Call Trace:
 [<ffffffff810892b2>] __might_sleep+0x102/0x130
 [<ffffffff8163b90f>] mutex_lock_nested+0x2f/0x50
 [<ffffffff81382c1c>] unbind_from_irq+0x2c/0x1b0
 [<ffffffff8110da66>] ? free_irq+0x56/0xb0
 [<ffffffff81382dbc>] unbind_from_irqhandler+0x1c/0x30
 [<ffffffff8138f06b>] xen_pcibk_disconnect+0x2b/0x80
 [<ffffffff81390348>] xen_pcibk_frontend_changed+0xe8/0x140
 [<ffffffff81387ac2>] xenbus_otherend_changed+0xd2/0x150
 [<ffffffff810895c1>] ? get_parent_ip+0x11/0x50
 [<ffffffff81387de0>] frontend_changed+0x10/0x20
 [<ffffffff81385712>] xenwatch_thread+0xb2/0x180

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
drivers/xen/xen-pciback/pciback.h
drivers/xen/xen-pciback/xenbus.c