linux-2626-support-20080608

[openafs.git] / src / afs / LINUX / osi_groups.c

diff --git a/src/afs/LINUX/osi_groups.c b/src/afs/LINUX/osi_groups.c
index ed7516c..93584ef 100644 (file)
--- a/src/afs/LINUX/osi_groups.c
+++ b/src/afs/LINUX/osi_groups.c
@@ -51,12 +51,14 @@ afs_setgroups(cred_t **cr, struct group_info *group_info, int change_parent)
 
     crset(*cr);
 
+#ifdef STRUCT_TASK_STRUCT_HAS_PARENT
     if (change_parent) {
        old_info = current->parent->group_info;
        get_group_info(group_info);
        current->parent->group_info = group_info;
        put_group_info(old_info);
     }
+#endif
 
     return (0);
 }
@@ -223,7 +225,8 @@ __setpag(cred_t **cr, afs_uint32 pagvalue, afs_uint32 *newpag,
 }
 
 #ifdef LINUX_KEYRING_SUPPORT
-static struct key_type *__key_type_keyring;
+extern struct key_type key_type_keyring __attribute__((weak));
+static struct key_type *__key_type_keyring = &key_type_keyring;
 
 static int
 install_session_keyring(struct task_struct *task, struct key *keyring)
@@ -624,28 +627,43 @@ extern rwlock_t tasklist_lock __attribute__((weak));
 void osi_keyring_init(void)
 {
     struct task_struct *p;
-#ifdef EXPORTED_TASKLIST_LOCK
-    if (&tasklist_lock)
-      read_lock(&tasklist_lock);
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
-#ifdef EXPORTED_TASKLIST_LOCK
-    else
-#endif
-      rcu_read_lock();
-#endif
-    p = find_task_by_pid(1);
-    if (p && p->user->session_keyring)
-       __key_type_keyring = p->user->session_keyring->type;
-#ifdef EXPORTED_TASKLIST_LOCK
-    if (&tasklist_lock)
-       read_unlock(&tasklist_lock);
-#endif
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
-#ifdef EXPORTED_TASKLIST_LOCK
-    else
+
+    /* If we can't lock the tasklist, either with its explicit lock,
+     * or by using the RCU lock, then we can't safely work out the 
+     * type of a keyring. So, we have to rely on the weak reference. 
+     * If that's not available, then keyring based PAGs won't work.
+     */
+    
+#if defined(EXPORTED_TASKLIST_LOCK) || (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(EXPORTED_RCU_READ_LOCK))
+    if (__key_type_keyring == NULL) {
+# ifdef EXPORTED_TASKLIST_LOCK
+       if (&tasklist_lock)
+           read_lock(&tasklist_lock);
+# endif
+# if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(EXPORTED_RCU_READ_LOCK))
+#  ifdef EXPORTED_TASKLIST_LOCK
+       else
+#  endif
+           rcu_read_lock();
+# endif
+#if defined(EXPORTED_FIND_TASK_BY_PID)
+       p = find_task_by_pid(1);
+#else
+       p = find_task_by_vpid(1);
 #endif
-      rcu_read_unlock();
+       if (p && p->user->session_keyring)
+           __key_type_keyring = p->user->session_keyring->type;
+# ifdef EXPORTED_TASKLIST_LOCK
+       if (&tasklist_lock)
+           read_unlock(&tasklist_lock);
+# endif
+# if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16) && defined(EXPORTED_RCU_READ_LOCK))
+#  ifdef EXPORTED_TASKLIST_LOCK
+       else
+#  endif
+           rcu_read_unlock();
+# endif
+    }
 #endif
 
     register_key_type(&key_type_afs_pag);