diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/dahdi/dahdi-base.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/drivers/dahdi/dahdi-base.c b/drivers/dahdi/dahdi-base.c index 50116fb..608da1b 100644 --- a/drivers/dahdi/dahdi-base.c +++ b/drivers/dahdi/dahdi-base.c @@ -476,9 +476,54 @@ static LIST_HEAD(span_list); static struct dahdi_chan *chans[DAHDI_MAX_CHANNELS]; -static inline struct dahdi_chan *chan_from_num(unsigned int channo) +static struct dahdi_chan *chan_from_num(unsigned int channo) { - return valid_channo(channo) ? chans[channo] : NULL; + struct dahdi_span *s; + struct pseudo_chan *pseudo; + + if (!unlikely(valid_channo(channo))) + return NULL; + + mutex_lock(®istration_mutex); + + /* When searching for the channel amongst the spans, we can use the + * fact that channels on a span must be numbered consecutively to skip + * checking each individual channel. */ + list_for_each_entry(s, &span_list, node) { + unsigned int basechan; + struct dahdi_chan *chan; + + if (unlikely(!s->channels)) + continue; + + basechan = s->chans[0]->channo; + if (channo >= (basechan + s->channels)) + continue; + + if (unlikely(channo < basechan)) { + /* Looks like they are asking for a channel that has + * already been removed. */ + mutex_unlock(®istration_mutex); + return NULL; + } + + chan = s->chans[channo - basechan]; + WARN_ON(chan->channo != channo); + mutex_unlock(®istration_mutex); + return chan; + } + + /* If we didn't find the channel on the list of real channels, then + * it's most likely a pseudo channel. */ + list_for_each_entry(pseudo, &pseudo_chans, node) { + if (pseudo->chan.channo == channo) { + mutex_unlock(®istration_mutex); + return &pseudo->chan; + } + } + + mutex_unlock(®istration_mutex); + return NULL; } static inline struct dahdi_chan *chan_from_file(struct file *file) |