[PATCH tip/core/rcu 09/12] fs: Substitute rcu_access_pointer() for rcu_dereference_raw()

From: Paul E. McKenney
Date: Mon Feb 17 2014 - 16:38:36 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

(Trivial patch.)

If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded to
rcu_access_pointer(). This commit makes this downgrade in __alloc_fd(),
which simply compares the RCU-protected pointer against NULL with no
dereferencing.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
fs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/file.c b/fs/file.c
index db25c2bdfe46..18f7d27855c4 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -497,7 +497,7 @@ repeat:
error = fd;
#if 1
/* Sanity check */
- if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
+ if (rcu_access_pointer(fdt->fd[fd]) != NULL) {
printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
rcu_assign_pointer(fdt->fd[fd], NULL);
}
--
1.8.1.5

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