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xen/evtchn: don't do unbind_from_irqhandler under spinlock

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unbind_from_irqhandler can end up doing /proc operations, which can't
happen under a spinlock.  So before removing the IRQ handler,
disable the irq under the port_user lock (masking the underlying event
channel and making sure the irq handler isn't running concurrently and
won't start running), then remove the handler without the lock.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
This commit is contained in:
Jeremy Fitzhardinge 2010-05-28 15:28:27 -07:00
parent 1a1a17cddb
commit 3f5e554f66
1 changed files with 11 additions and 2 deletions
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13
drivers/xen/evtchn.c
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@ -375,10 +375,12 @@ static long evtchn_ioctl(struct file *file,
break;
}
evtchn_unbind_from_user(u, unbind.port);
disable_irq(irq_from_evtchn(unbind.port));
spin_unlock_irq(&port_user_lock);
evtchn_unbind_from_user(u, unbind.port);
rc = 0;
break;
}
@ -484,11 +486,18 @@ static int evtchn_release(struct inode *inode, struct file *filp)
if (get_port_user(i) != u)
continue;
evtchn_unbind_from_user(get_port_user(i), i);
disable_irq(irq_from_evtchn(i));
}
spin_unlock_irq(&port_user_lock);
for (i = 0; i < NR_EVENT_CHANNELS; i++) {
if (get_port_user(i) != u)
continue;
evtchn_unbind_from_user(get_port_user(i), i);
}
kfree(u->name);
kfree(u);