[PATCH] files: lock-free fd look-up

With the use of RCU in files structure, the look-up of files using fds can now
be lock-free.  The lookup is protected by rcu_read_lock()/rcu_read_unlock().
This patch changes the readers to use lock-free lookup.

Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Ravikiran Thirumalai <kiran_th@gmail.com>
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/fcntl.c b/fs/fcntl.c
index d2f3ed8acd93..863b46e0d78a 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -40,10 +40,10 @@ static inline int get_close_on_exec(unsigned int fd)
         struct files_struct *files = current->files;
         struct fdtable *fdt;
         int res;
-        spin_lock(&files->file_lock);
+        rcu_read_lock();
         fdt = files_fdtable(files);
         res = FD_ISSET(fd, fdt->close_on_exec);
-        spin_unlock(&files->file_lock);
+        rcu_read_unlock();
         return res;
 }