[gamin] fix possible server deadlock in ih_sub_cancel

[Olav Vitters <ovitters src gnome org>]

commit f9c67a13af33f389429e4e760f2023a23a9ac19f
Author: Anssi Hannula <anssi mageia org>
Date:   Wed Jan 4 00:23:55 2012 +0200

    fix possible server deadlock in ih_sub_cancel
    
    ih_sub_foreach() calls ih_sub_cancel() while inotify_lock is locked.
    However, ih_sub_cancel() locks it again, and locking GMutex recursively
    causes undefined behaviour.
    
    Fix that by removing locking from ih_sub_cancel() as ih_sub_foreach()
    is its only user. Also make the function static so that it won't
    accidentally get used by other files without locking (inotify-helper.h
    is an internal server header).
    
    This should fix the intermittent deadlocks I've been experiencing
    causing KDE applications to no longer start, and probably also
    http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=542361

 server/inotify-helper.c |    7 ++-----
 server/inotify-helper.h |    1 -
 2 files changed, 2 insertions(+), 6 deletions(-)
---
diff --git a/server/inotify-helper.c b/server/inotify-helper.c
index d77203e..0789fa4 100644
--- a/server/inotify-helper.c
+++ b/server/inotify-helper.c
@@ -123,13 +123,11 @@ ih_sub_add (ih_sub_t * sub)
 
 /**
  * Cancels a subscription which was being monitored.
+ * inotify_lock must be held when calling.
  */
-gboolean
+static gboolean
 ih_sub_cancel (ih_sub_t * sub)
 {
-       G_LOCK(inotify_lock);
-
-
        if (!sub->cancelled)
        {
                IH_W("cancelling %s\n", sub->pathname);
@@ -140,7 +138,6 @@ ih_sub_cancel (ih_sub_t * sub)
                sub_list = g_list_remove (sub_list, sub);
        }
 
-       G_UNLOCK(inotify_lock);
        return TRUE;
 }
 
diff --git a/server/inotify-helper.h b/server/inotify-helper.h
index 5d3b6d0..d36b5fd 100644
--- a/server/inotify-helper.h
+++ b/server/inotify-helper.h
@@ -34,7 +34,6 @@ gboolean       ih_startup             (event_callback_t ecb,
                                         found_callback_t fcb);
 gboolean        ih_running             (void);
 gboolean        ih_sub_add             (ih_sub_t *sub);
-gboolean        ih_sub_cancel          (ih_sub_t *sub);
 
 /* Return FALSE from 'f' if the subscription should be cancelled */
 void            ih_sub_foreach         (void *callerdata, gboolean (*f)(ih_sub_t *sub, void *callerdata));