From 889ab7e2ab312aeeb481c460504314b1a95769d0 Mon Sep 17 00:00:00 2001 From: Shaun Ruffell Date: Mon, 3 Jan 2011 18:28:06 +0000 Subject: dahdi: Drop 'chans' reference in chan_from_num. Part of getting rid of global chans array. We need to search the list of spans and the list of pseudo channels. While this is slower than a direct index into a 'chans' array, the places where this function is called are not in the 'hot' path but instead part of channel configuration and conferencing setup. Signed-off-by: Shaun Ruffell Acked-by: Kinsey Moore git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@9607 a0bf4364-ded3-4de4-8d8a-66a801d63aff --- drivers/dahdi/dahdi-base.c | 49 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 47 insertions(+), 2 deletions(-) (limited to 'drivers/dahdi') 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) -- cgit v1.2.3