[svn-commits] sruffell: linux/trunk r9414 - /linux/trunk/drivers/dahdi/dahdi-base.c
SVN commits to the Digium repositories
svn-commits at lists.digium.com
Fri Sep 24 17:45:10 CDT 2010
Author: sruffell
Date: Fri Sep 24 17:45:07 2010
New Revision: 9414
URL: http://svnview.digium.com/svn/dahdi?view=rev&rev=9414
Log:
dahdi: Remove bigzaplock by converting chan_lock to spinlock_t.
The bigzaplock was used to prevent changes to all the channels during
masterspan processing while conference parameters were changing. The
master span processing also took a global lock out on the chan_lock to
prevent new channels from being registered or unregistered during
processing. Instead of grabbing both those locks, just changing the
semantics of chan_lock to those of bigzaplock seems to fit the bill and
removes another lock from the driver (and saves ~10 ns on a 2.40 GHz
Xeon in prcocess_masterspan)
chan_lock is a candidate for conversion to RCU but usage in conferencing
(bigzaplock type usage) needs to be audited carefully before conversion.
Signed-off-by: Shaun Ruffell <sruffell at digium.com>
Acked-by: Kinsey Moore <kmoore at digium.com>
Acked-by: Russ Meyerriecks <rmeyerriecks at digium.com>
Acked-by: Tzafrir Cohen <tzafrir.cohen at xorcom.com>
Review: https://reviewboard.asterisk.org/r/940/
Modified:
linux/trunk/drivers/dahdi/dahdi-base.c
Modified: linux/trunk/drivers/dahdi/dahdi-base.c
URL: http://svnview.digium.com/svn/dahdi/linux/trunk/drivers/dahdi/dahdi-base.c?view=diff&rev=9414&r1=9413&r2=9414
==============================================================================
--- linux/trunk/drivers/dahdi/dahdi-base.c (original)
+++ linux/trunk/drivers/dahdi/dahdi-base.c Fri Sep 24 17:45:07 2010
@@ -376,7 +376,6 @@
static LIST_HEAD(dahdi_timers);
static DEFINE_SPINLOCK(dahdi_timer_lock);
-static DEFINE_SPINLOCK(bigzaplock);
struct dahdi_zone {
atomic_t refcount;
@@ -398,11 +397,11 @@
#ifdef DEFINE_RWLOCK
static DEFINE_RWLOCK(zone_lock);
-static DEFINE_RWLOCK(chan_lock);
#else
static rwlock_t zone_lock = RW_LOCK_UNLOCKED;
-static rwlock_t chan_lock = RW_LOCK_UNLOCKED;
-#endif
+#endif
+
+static DEFINE_SPINLOCK(chan_lock);
struct pseudo_chan {
struct dahdi_chan chan;
@@ -1655,7 +1654,7 @@
dahdi_set_law(chan, DAHDI_LAW_DEFAULT);
close_channel(chan);
- write_lock_irqsave(&chan_lock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
for (x = 1; x < DAHDI_MAX_CHANNELS; x++) {
if (chans[x])
continue;
@@ -1669,7 +1668,7 @@
set_bit(DAHDI_FLAGBIT_REGISTERED, &chan->flags);
break;
}
- write_unlock_irqrestore(&chan_lock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
if (DAHDI_MAX_CHANNELS == x) {
module_printk(KERN_ERR, "No more channels available\n");
return -ENOMEM;
@@ -2075,7 +2074,7 @@
chan->hdlcnetdev = NULL;
}
#endif
- write_lock_irqsave(&chan_lock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
if (test_bit(DAHDI_FLAGBIT_REGISTERED, &chan->flags)) {
chans[chan->channo] = NULL;
clear_bit(DAHDI_FLAGBIT_REGISTERED, &chan->flags);
@@ -2113,7 +2112,7 @@
}
}
chan->channo = -1;
- write_unlock_irqrestore(&chan_lock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
}
static ssize_t dahdi_chan_read(struct file *file, char __user *usrbuf,
@@ -2914,9 +2913,9 @@
return NULL;
}
- write_lock_irqsave(&chan_lock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
list_add_tail(&pseudo->node, &pseudo_chans);
- write_unlock_irqrestore(&chan_lock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
snprintf(pseudo->chan.name, sizeof(pseudo->chan.name)-1,
"Pseudo/%d", pseudo->chan.channo);
@@ -2934,9 +2933,9 @@
pseudo = chan_to_pseudo(chan);
- write_lock_irqsave(&chan_lock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
list_del(&pseudo->node);
- write_unlock_irqrestore(&chan_lock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
dahdi_chan_unreg(chan);
kfree(pseudo);
@@ -4864,14 +4863,14 @@
if ((!conf.confmode) && conf.confno)
return -EINVAL;
conf.chan = chan->channo; /* return with real channel # */
- spin_lock_irqsave(&bigzaplock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
spin_lock(&chan->lock);
if (conf.confno == -1)
conf.confno = dahdi_first_empty_conference();
if ((conf.confno < 1) && (conf.confmode)) {
/* No more empty conferences */
spin_unlock(&chan->lock);
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
return -EBUSY;
}
/* if changing confs, clear last added info */
@@ -4922,7 +4921,7 @@
}
spin_unlock(&chan->lock);
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
if (copy_to_user((void __user *)data, &conf, sizeof(conf)))
return -EFAULT;
return 0;
@@ -4952,7 +4951,7 @@
if (conf.chan && (conf.chan == conf.confno))
return -EINVAL;
- spin_lock_irqsave(&bigzaplock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
spin_lock(&chan->lock);
/* if to clear all links */
@@ -4961,7 +4960,7 @@
memset(conf_links, 0, sizeof(conf_links));
recalc_maxlinks();
spin_unlock(&chan->lock);
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
return 0;
}
/* look for already existant specified combination */
@@ -5000,7 +4999,7 @@
}
recalc_maxlinks();
spin_unlock(&chan->lock);
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
return res;
}
@@ -5289,9 +5288,9 @@
case DAHDI_CONFMUTE: /* set confmute flag */
get_user(j, (int __user *)data); /* get conf # */
if (!(chan->flags & DAHDI_FLAG_AUDIO)) return (-EINVAL);
- spin_lock_irqsave(&bigzaplock, flags);
+ spin_lock_irqsave(&chan_lock, flags);
chan->confmute = j;
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
break;
case DAHDI_GETCONFMUTE: /* get confmute flag */
if (!(chan->flags & DAHDI_FLAG_AUDIO)) return (-EINVAL);
@@ -8455,10 +8454,10 @@
* to be called (1000 / (DAHDI_CHUNKSIZE / 8)) times per second. */
atomic_inc(&core_timer.count);
#endif
- /* Hold the big zap lock for the duration of major
+ /* Hold the chan_lock for the duration of major
activities which touch all sorts of channels */
- spin_lock_irqsave(&bigzaplock, flags);
- read_lock(&chan_lock);
+ spin_lock_irqsave(&chan_lock, flags);
+
/* Process any timers */
process_timers();
/* If we have dynamic stuff, call the ioctl with 0,0 parameters to
@@ -8542,8 +8541,7 @@
s->ops->sync_tick(s, s == master);
#endif
}
- read_unlock(&chan_lock);
- spin_unlock_irqrestore(&bigzaplock, flags);
+ spin_unlock_irqrestore(&chan_lock, flags);
}
#ifndef CONFIG_DAHDI_CORE_TIMER
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