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security: use READ_ONCE instead of deprecated ACCESS_ONCE

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With the new standardized functions, we can replace all ACCESS_ONCE()
calls across relevant security/keyrings/.

ACCESS_ONCE() does not work reliably on non-scalar types. For example
gcc 4.6 and 4.7 might remove the volatile tag for such accesses during
the SRA (scalar replacement of aggregates) step:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145

Update the new calls regardless of if it is a scalar type, this is
cleaner than having three alternatives.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Davidlohr Bueso 2017-06-08 14:47:34 +01:00 committed by James Morris
parent 47b2c3fff4
commit 381f20fceb
1 changed files with 6 additions and 6 deletions
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12
security/keys/keyring.c
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@ -706,7 +706,7 @@ static bool search_nested_keyrings(struct key *keyring,
* Non-keyrings avoid the leftmost branch of the root entirely (root * Non-keyrings avoid the leftmost branch of the root entirely (root
* slots 1-15). * slots 1-15).
*/ */
ptr = ACCESS_ONCE(keyring->keys.root); ptr = READ_ONCE(keyring->keys.root);
if (!ptr) if (!ptr)
goto not_this_keyring; goto not_this_keyring;
@ -720,7 +720,7 @@ static bool search_nested_keyrings(struct key *keyring,
if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
goto not_this_keyring; goto not_this_keyring;
ptr = ACCESS_ONCE(shortcut->next_node); ptr = READ_ONCE(shortcut->next_node);
node = assoc_array_ptr_to_node(ptr); node = assoc_array_ptr_to_node(ptr);
goto begin_node; goto begin_node;
} }
@ -740,7 +740,7 @@ static bool search_nested_keyrings(struct key *keyring,
if (assoc_array_ptr_is_shortcut(ptr)) { if (assoc_array_ptr_is_shortcut(ptr)) {
shortcut = assoc_array_ptr_to_shortcut(ptr); shortcut = assoc_array_ptr_to_shortcut(ptr);
smp_read_barrier_depends(); smp_read_barrier_depends();
ptr = ACCESS_ONCE(shortcut->next_node); ptr = READ_ONCE(shortcut->next_node);
BUG_ON(!assoc_array_ptr_is_node(ptr)); BUG_ON(!assoc_array_ptr_is_node(ptr));
} }
node = assoc_array_ptr_to_node(ptr); node = assoc_array_ptr_to_node(ptr);
@ -752,7 +752,7 @@ static bool search_nested_keyrings(struct key *keyring,
ascend_to_node: ascend_to_node:
/* Go through the slots in a node */ /* Go through the slots in a node */
for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
ptr = ACCESS_ONCE(node->slots[slot]); ptr = READ_ONCE(node->slots[slot]);
if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)
goto descend_to_node; goto descend_to_node;
@ -790,13 +790,13 @@ static bool search_nested_keyrings(struct key *keyring,
/* We've dealt with all the slots in the current node, so now we need /* We've dealt with all the slots in the current node, so now we need
* to ascend to the parent and continue processing there. * to ascend to the parent and continue processing there.
*/ */
ptr = ACCESS_ONCE(node->back_pointer); ptr = READ_ONCE(node->back_pointer);
slot = node->parent_slot; slot = node->parent_slot;
if (ptr && assoc_array_ptr_is_shortcut(ptr)) { if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
shortcut = assoc_array_ptr_to_shortcut(ptr); shortcut = assoc_array_ptr_to_shortcut(ptr);
smp_read_barrier_depends(); smp_read_barrier_depends();
ptr = ACCESS_ONCE(shortcut->back_pointer); ptr = READ_ONCE(shortcut->back_pointer);
slot = shortcut->parent_slot; slot = shortcut->parent_slot;
} }
if (!ptr) if (!ptr)