[PATCH] jffs2_gcd_mtd3, Stopping kernel threads timed out

[Uli Luckas <u.luckas@road.de>]

Hi
We experience the following problem when our board tries to suspend:

Jun  7 18:32:21 constin kernel: [ 2085.350000] Stopping tasks ... 
Jun  7 18:32:21 constin kernel: [ 2105.410000] Stopping kernel threads timed 
out after 20 seconds (1 tasks refusing to freeze):
Jun  7 18:32:21 constin kernel: [ 2105.410000]  jffs2_gcd_mtd3
Jun  7 18:32:21 constin kernel: [ 2105.410000] Restarting tasks ... <4> 
Strange, jffs2_gcd_mtd3 not stopped
Jun  7 18:32:21 constin kernel: [ 2105.440000] done.

The problem seems to happen, when suspend kicks in, after the call to 
try_to_freeze and before the while loop in jffs2_garbage_collect_thread.

The pending freeze will cause signal_pending to return true until the 
attempted suspend is over and thereby the while loop won't terminate until 
the suspend times out.

This patch will call try_to_freeze from within the while loop and adds an 
extra check for jffs2_thread_should_wake before we actually do the GC to 
avoid calling jffs2_garbage_collect_pass at every wakeup.

If there are no objections, please apply and push to mainline.

Signed-off-by: Uli Luckas <u.luckas@road.de>

diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c
index 888f236..f953824 100644
--- a/fs/jffs2/background.c
+++ b/fs/jffs2/background.c
@@ -96,9 +96,6 @@ static int jffs2_garbage_collect_thread(void *_c)
                        schedule();
                }
 
-               if (try_to_freeze())
-                       continue;
-
                /* This thread is purely an optimisation. But if it runs when
                   other things could be running, it actually makes things a
                   lot worse. Use yield() and put it at the back of the runqueue
@@ -113,6 +110,9 @@ static int jffs2_garbage_collect_thread(void *_c)
                        siginfo_t info;
                        unsigned long signr;
 
+                       if (try_to_freeze())
+                               continue;
+
                        signr = dequeue_signal_lock(current, &current->blocked, &info);
 
                        switch(signr) {
@@ -137,7 +137,8 @@ static int jffs2_garbage_collect_thread(void *_c)
                disallow_signal(SIGHUP);
 
                D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
-               if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
+               if (   jffs2_thread_should_wake(c) 
+                   && jffs2_garbage_collect_pass(c) == -ENOSPC) {
                        printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
                        goto die;
                }

-- 

------- ROAD ...the handyPC Company - - -  ) ) )

Uli Luckas
Software Development

ROAD GmbH
Bennigsenstr. 14 | 12159 Berlin | Germany
fon: +49 (30) 230069 - 64 | fax: +49 (30) 230069 - 69
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