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b43: Fix rfkill callback deadlock 

wl->mutex might already be locked on initialization.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Michael Buesch 2007-10-28 17:27:10 +01:00 committed by Jeff Garzik
parent ce2d90591f
commit 80fda03fc8
1 changed files with 10 additions and 4 deletions
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14
drivers/net/wireless/b43/rfkill.c
View File

@ -61,15 +61,22 @@ static void b43_rfkill_poll(struct input_polled_dev *poll_dev)
mutex_unlock(&wl->mutex); mutex_unlock(&wl->mutex);
} }
/* Called when the RFKILL toggled in software. /* Called when the RFKILL toggled in software. */
* This is called without locking. */
static int b43_rfkill_soft_toggle(void *data, enum rfkill_state state) static int b43_rfkill_soft_toggle(void *data, enum rfkill_state state)
{ {
struct b43_wldev *dev = data; struct b43_wldev *dev = data;
struct b43_wl *wl = dev->wl; struct b43_wl *wl = dev->wl;
int err = 0; int err = 0;
mutex_lock(&wl->mutex); /* When RFKILL is registered, it will call back into this callback.
* wl->mutex will already be locked when this happens.
* So first trylock. On contention check if we are in initialization.
* Silently return if that happens to avoid a deadlock. */
if (mutex_trylock(&wl->mutex) == 0) {
if (b43_status(dev) < B43_STAT_INITIALIZED)
return 0;
mutex_lock(&wl->mutex);
}
if (b43_status(dev) < B43_STAT_INITIALIZED) if (b43_status(dev) < B43_STAT_INITIALIZED)
goto out_unlock; goto out_unlock;
@ -89,7 +96,6 @@ static int b43_rfkill_soft_toggle(void *data, enum rfkill_state state)
b43_radio_turn_off(dev, 0); b43_radio_turn_off(dev, 0);
break; break;
} }
out_unlock: out_unlock:
mutex_unlock(&wl->mutex); mutex_unlock(&wl->mutex);