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dahdi: dahdi_chan.ec_factory can be protected with the mutex. 

This is never accessed or modified in interrupt context. This closes a potential
race if the echocan is being changed on a channel while enabling disabling is
hapening on another thread.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
This commit is contained in:
Shaun Ruffell 2014-06-19 16:45:41 -05:00 committed by Russ Meyerriecks
parent 761e02da52
commit a3578ca156
1 changed files with 10 additions and 9 deletions
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19
drivers/dahdi/dahdi-base.c
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@ -991,10 +991,13 @@ static int dahdi_seq_show(struct seq_file *sfile, void *data)
seq_fill_alarm_string(sfile, chan->chan_alarms);
if (chan->ec_factory)
mutex_lock(&chan->mutex);
if (chan->ec_factory) {
seq_printf(sfile, "(EC: %s - %s) ",
chan->ec_factory->get_name(chan),
chan->ec_state ? "ACTIVE" : "INACTIVE");
}
mutex_unlock(&chan->mutex);
seq_printf(sfile, "\n");
}
@ -1489,14 +1492,13 @@ static const struct dahdi_echocan_factory hwec_factory = {
static int dahdi_enable_hw_preechocan(struct dahdi_chan *chan)
{
int res;
unsigned long flags;
spin_lock_irqsave(&chan->lock, flags);
mutex_lock(&chan->mutex);
if (chan->ec_factory != &hwec_factory)
res = -ENODEV;
else
res = 0;
spin_unlock_irqrestore(&chan->lock, flags);
mutex_unlock(&chan->mutex);
if (-ENODEV == res)
return 0;
@ -2303,10 +2305,10 @@ static void dahdi_chan_unreg(struct dahdi_chan *chan)
*/
}
spin_lock_irqsave(&chan->lock, flags);
mutex_lock(&chan->mutex);
release_echocan(chan->ec_factory);
chan->ec_factory = NULL;
spin_unlock_irqrestore(&chan->lock, flags);
mutex_unlock(&chan->mutex);
#ifdef CONFIG_DAHDI_NET
if (dahdi_have_netdev(chan)) {
@ -5227,7 +5229,6 @@ static bool dahdi_is_hwec_available(const struct dahdi_chan *chan)
static int dahdi_ioctl_attach_echocan(unsigned long data)
{
unsigned long flags;
struct dahdi_chan *chan;
struct dahdi_attach_echocan ae;
const struct dahdi_echocan_factory *new = NULL, *old;
@ -5269,10 +5270,10 @@ static int dahdi_ioctl_attach_echocan(unsigned long data)
}
}
spin_lock_irqsave(&chan->lock, flags);
mutex_lock(&chan->mutex);
old = chan->ec_factory;
chan->ec_factory = new;
spin_unlock_irqrestore(&chan->lock, flags);
mutex_unlock(&chan->mutex);
if (old)
release_echocan(old);