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rfkill: mutex fixes 

There are two mutexes in rfkill:

rfkill->mutex, which protects some of the fields of a rfkill struct, and is
also used for callback serialization.

rfkill_mutex, which protects the global state, the list of registered
rfkill structs and rfkill->claim.

Make sure to use the correct mutex, and to not miss locking rfkill->mutex
even when we already took rfkill_mutex.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Henrique de Moraes Holschuh 2008-07-21 21:18:20 -03:00 committed by John W. Linville
parent f1b23361a0
commit 064af1117b
1 changed files with 19 additions and 10 deletions
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29
net/rfkill/rfkill.c
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@ -150,7 +150,7 @@ static void update_rfkill_state(struct rfkill *rfkill)
* even if the radio is in RFKILL_STATE_HARD_BLOCKED state, so as to
* give the driver a hint that it should double-BLOCK the transmitter.
*
* Caller must have aquired rfkill_mutex.
* Caller must have acquired rfkill->mutex.
*/
static int rfkill_toggle_radio(struct rfkill *rfkill,
enum rfkill_state state,
@ -216,8 +216,11 @@ void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
rfkill_states[type] = state;
list_for_each_entry(rfkill, &rfkill_list, node) {
if ((!rfkill->user_claim) && (rfkill->type == type))
if ((!rfkill->user_claim) && (rfkill->type == type)) {
mutex_lock(&rfkill->mutex);
rfkill_toggle_radio(rfkill, state, 0);
mutex_unlock(&rfkill->mutex);
}
}
mutex_unlock(&rfkill_mutex);
@ -228,7 +231,7 @@ EXPORT_SYMBOL(rfkill_switch_all);
* rfkill_epo - emergency power off all transmitters
*
* This kicks all rfkill devices to RFKILL_STATE_SOFT_BLOCKED, ignoring
* everything in its path but rfkill_mutex.
* everything in its path but rfkill_mutex and rfkill->mutex.
*/
void rfkill_epo(void)
{
@ -236,7 +239,9 @@ void rfkill_epo(void)
mutex_lock(&rfkill_mutex);
list_for_each_entry(rfkill, &rfkill_list, node) {
mutex_lock(&rfkill->mutex);
rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
mutex_unlock(&rfkill->mutex);
}
mutex_unlock(&rfkill_mutex);
}
@ -372,6 +377,9 @@ static ssize_t rfkill_claim_store(struct device *dev,
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (rfkill->user_claim_unsupported)
return -EOPNOTSUPP;
/*
* Take the global lock to make sure the kernel is not in
* the middle of rfkill_switch_all
@ -380,19 +388,17 @@ static ssize_t rfkill_claim_store(struct device *dev,
if (error)
return error;
if (rfkill->user_claim_unsupported) {
error = -EOPNOTSUPP;
goto out_unlock;
}
if (rfkill->user_claim != claim) {
if (!claim)
if (!claim) {
mutex_lock(&rfkill->mutex);
rfkill_toggle_radio(rfkill,
rfkill_states[rfkill->type],
0);
mutex_unlock(&rfkill->mutex);
}
rfkill->user_claim = claim;
}
out_unlock:
mutex_unlock(&rfkill_mutex);
return error ? error : count;
@ -521,8 +527,11 @@ static void rfkill_remove_switch(struct rfkill *rfkill)
{
mutex_lock(&rfkill_mutex);
list_del_init(&rfkill->node);
rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
mutex_unlock(&rfkill_mutex);
mutex_lock(&rfkill->mutex);
rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
mutex_unlock(&rfkill->mutex);
}
/**