mini-os: Fix crash on frontend shutdown failures

Do not free frontend resources if some error happened, since the
backend may not have finished properly restarting in such case.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
xen-unstable changeset:   21114:d7ee309d0e01
xen-unstable date:        Wed Apr 07 08:16:15 2010 +0100

extras/mini-os/blkfront.c

@@ -302,7 +302,8 @@ close:
     snprintf(path, sizeof(path), "%s/event-channel", nodename);
     xenbus_rm(XBT_NIL, path);
 
-    free_blkfront(dev);
+    if (!err)
+        free_blkfront(dev);
 }
 
 static void blkfront_wait_slot(struct blkfront_dev *dev)

extras/mini-os/fbfront.c

@@ -287,7 +287,8 @@ close_kbdfront:
     snprintf(path, sizeof(path), "%s/request-abs-pointer", nodename);
     xenbus_rm(XBT_NIL, path);
 
-    free_kbdfront(dev);
+    if (!err)
+        free_kbdfront(dev);
 }
 
 #ifdef HAVE_LIBC
@@ -680,7 +681,8 @@ close_fbfront:
     snprintf(path, sizeof(path), "%s/feature-update", nodename);
     xenbus_rm(XBT_NIL, path);
 
-    free_fbfront(dev);
+    if (!err)
+        free_fbfront(dev);
 }
 
 #ifdef HAVE_LIBC

extras/mini-os/netfront.c

@@ -562,7 +562,8 @@ close:
     snprintf(path, sizeof(path), "%s/request-rx-copy", nodename);
     xenbus_rm(XBT_NIL, path);
 
-    free_netfront(dev);
+    if (!err)
+        free_netfront(dev);
 }
 
 

extras/mini-os/pcifront.c

@@ -377,7 +377,8 @@ close_pcifront:
     snprintf(path, sizeof(path), "%s/event-channel", nodename);
     xenbus_rm(XBT_NIL, path);
 
-    free_pcifront(dev);
+    if (!err)
+        free_pcifront(dev);
 }
 
 int pcifront_physical_to_virtual (struct pcifront_dev *dev,