[dahdi-commits] sruffell: branch linux/2.2 r6934 - in /linux/branches/2.2: ./ drivers/dahdi/

[SVN commits to the DAHDI project]

Author: sruffell
Date: Tue Aug  4 11:24:24 2009
New Revision: 6934

URL: http://svn.asterisk.org/svn-view/dahdi?view=rev&rev=6934
Log:
Merged revisions 6933 via svnmerge from 
https://origsvn.digium.com/svn/dahdi/linux/trunk

........
  r6933 | sruffell | 2009-08-04 11:22:39 -0500 (Tue, 04 Aug 2009) | 10 lines
  
  dahdi_dummy: Do not allow jumps in system time to lock up the system.
  
  Since dahdi_dummy uses the number of milliseconds that has actually passed to
  determine how many times to call dahdi_receive, it is possible that if the
  system time shifts after dahdi is started, that the system can appear to lock
  up while dahdi_dummy attempts to catch up.  This change prevents soft lock ups
  under these conditions.
  
  (closes issue #15647)
  Reported by: missnebun
........

Modified:
    linux/branches/2.2/   (props changed)
    linux/branches/2.2/drivers/dahdi/dahdi_dummy.c

Propchange: linux/branches/2.2/
------------------------------------------------------------------------------
--- svnmerge-integrated (original)
+++ svnmerge-integrated Tue Aug  4 11:24:24 2009
@@ -1,1 +1,1 @@
-/linux/trunk:1-6696,6712-6713,6715-6716,6718-6759,6761-6767,6769-6770,6772-6779,6781-6784,6786-6790,6792-6793,6795-6796,6798-6803,6844-6863
+/linux/trunk:1-6696,6712-6713,6715-6716,6718-6759,6761-6767,6769-6770,6772-6779,6781-6784,6786-6790,6792-6793,6795-6796,6798-6803,6844-6863,6933

Modified: linux/branches/2.2/drivers/dahdi/dahdi_dummy.c
URL: http://svn.asterisk.org/svn-view/dahdi/linux/branches/2.2/drivers/dahdi/dahdi_dummy.c?view=diff&rev=6934&r1=6933&r2=6934
==============================================================================
--- linux/branches/2.2/drivers/dahdi/dahdi_dummy.c (original)
+++ linux/branches/2.2/drivers/dahdi/dahdi_dummy.c Tue Aug  4 11:24:24 2009
@@ -161,12 +161,31 @@
 	unsigned long ms_since_start;
 	struct timespec now;
 	const unsigned long MAX_INTERVAL = 100000L;
+	const unsigned long MS_LIMIT = 3000;
 
 	if (!atomic_read(&shutdown))
 		mod_timer(&timer, jiffies + JIFFIES_INTERVAL);
 
 	now = current_kernel_time();
 	ms_since_start = timespec_diff_ms(&ztd->start_interval, &now);
+	
+	/*
+	 * If the system time has changed, it is possible for us to be far
+	 * behind.  If we are more than MS_LIMIT milliseconds behind, just
+	 * reset our time base and continue so that we do not hang the system
+	 * here.
+	 *
+	 */
+	if (unlikely((ms_since_start - ztd->calls_since_start) > MS_LIMIT)) {
+		if (printk_ratelimit()) {
+			printk(KERN_INFO
+			       "dahdi_dummy: Detected time shift.\n");
+		}
+		ztd->calls_since_start = 0;
+		ztd->start_interval = now;
+		return;
+	}
+
 	while (ms_since_start > ztd->calls_since_start) {
 		ztd->calls_since_start++;
 		dahdi_receive(&ztd->span);