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Subject[PATCH 02/23] security: use READ_ONCE instead of deprecated ACCESS_ONCE
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From: Davidlohr Bueso <dave@stgolabs.net>

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>
---

security/keys/keyring.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 4d1678e4586f..de81793f9920 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -706,7 +706,7 @@ static bool search_nested_keyrings(struct key *keyring,
* Non-keyrings avoid the leftmost branch of the root entirely (root
* slots 1-15).
*/
- ptr = ACCESS_ONCE(keyring->keys.root);
+ ptr = READ_ONCE(keyring->keys.root);
if (!ptr)
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)
goto not_this_keyring;

- ptr = ACCESS_ONCE(shortcut->next_node);
+ ptr = READ_ONCE(shortcut->next_node);
node = assoc_array_ptr_to_node(ptr);
goto begin_node;
}
@@ -740,7 +740,7 @@ static bool search_nested_keyrings(struct key *keyring,
if (assoc_array_ptr_is_shortcut(ptr)) {
shortcut = assoc_array_ptr_to_shortcut(ptr);
smp_read_barrier_depends();
- ptr = ACCESS_ONCE(shortcut->next_node);
+ ptr = READ_ONCE(shortcut->next_node);
BUG_ON(!assoc_array_ptr_is_node(ptr));
}
node = assoc_array_ptr_to_node(ptr);
@@ -752,7 +752,7 @@ static bool search_nested_keyrings(struct key *keyring,
ascend_to_node:
/* Go through the slots in a node */
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)
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
* 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;

if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
shortcut = assoc_array_ptr_to_shortcut(ptr);
smp_read_barrier_depends();
- ptr = ACCESS_ONCE(shortcut->back_pointer);
+ ptr = READ_ONCE(shortcut->back_pointer);
slot = shortcut->parent_slot;
}
if (!ptr)
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