keyring: Remove now-redundant smp_read_barrier_depends()

Now that the associative-array library properly heads dependency chains,
the various smp_read_barrier_depends() calls in security/keys/keyring.c
are no longer needed.  This commit therefore removes them.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: <keyrings@vger.kernel.org>
Cc: <linux-security-module@vger.kernel.org>
Reviewed-by: James Morris <james.l.morris@oracle.com>

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index d0bccebbd3b51cedb842ce574f65d448856650c0..41bcf57e96f21c5eef258b72a1b119b2fda172fd 100644 (file)
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -713,7 +713,6 @@ descend_to_keyring:
                 * doesn't contain any keyring pointers.
                 */
                shortcut = assoc_array_ptr_to_shortcut(ptr);
-               smp_read_barrier_depends();
                if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
                        goto not_this_keyring;
 
@@ -723,8 +722,6 @@ descend_to_keyring:
        }
 
        node = assoc_array_ptr_to_node(ptr);
-       smp_read_barrier_depends();
-
        ptr = node->slots[0];
        if (!assoc_array_ptr_is_meta(ptr))
                goto begin_node;
@@ -736,7 +733,6 @@ descend_to_node:
        kdebug("descend");
        if (assoc_array_ptr_is_shortcut(ptr)) {
                shortcut = assoc_array_ptr_to_shortcut(ptr);
-               smp_read_barrier_depends();
                ptr = READ_ONCE(shortcut->next_node);
                BUG_ON(!assoc_array_ptr_is_node(ptr));
        }
@@ -744,7 +740,6 @@ descend_to_node:
 
 begin_node:
        kdebug("begin_node");
-       smp_read_barrier_depends();
        slot = 0;
 ascend_to_node:
        /* Go through the slots in a node */
@@ -792,14 +787,12 @@ ascend_to_node:
 
        if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
                shortcut = assoc_array_ptr_to_shortcut(ptr);
-               smp_read_barrier_depends();
                ptr = READ_ONCE(shortcut->back_pointer);
                slot = shortcut->parent_slot;
        }
        if (!ptr)
                goto not_this_keyring;
        node = assoc_array_ptr_to_node(ptr);
-       smp_read_barrier_depends();
        slot++;
 
        /* If we've ascended to the root (zero backpointer), we must have just