[PATCH RFC tip/core/rcu 15/15] keyring: Remove now-redundant smp_read_barrier_depends()

[Paul E. McKenney]

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 <paul...@linux.vnet.ibm.com>
Cc: David Howells <dhowe...@redhat.com>
Cc: James Morris <james.l.mor...@oracle.com>
Cc: "Serge E. Hallyn" <se...@hallyn.com>
Cc: <keyri...@vger.kernel.org>
Cc: <linux-security-mod...@vger.kernel.org>
---
 security/keys/keyring.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 4fa82a8a9c0e..fb44c9169125 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -712,7 +712,6 @@ static bool search_nested_keyrings(struct key *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;
 
@@ -722,8 +721,6 @@ static bool search_nested_keyrings(struct key *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;
@@ -735,7 +732,6 @@ static bool search_nested_keyrings(struct key *keyring,
        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));
        }
@@ -743,7 +739,6 @@ static bool search_nested_keyrings(struct key *keyring,
 
 begin_node:
        kdebug("begin_node");
-       smp_read_barrier_depends();
        slot = 0;
 ascend_to_node:
        /* Go through the slots in a node */
@@ -791,14 +786,12 @@ static bool search_nested_keyrings(struct key *keyring,
 
        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
-- 
2.5.2