proc: don't do dummy rcu_read_lock/rcu_read_unlock on error path

rcu_read_lock()/rcu_read_unlock() is nop for TINY_RCU, but is not a nop
for, say, PREEMPT_RCU.

proc_fill_cache() is called without RCU lock, there is no need to
lock/unlock on error path, simply jump out of the loop.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 155dee600ed4..0f928cbba4a4 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1928,21 +1928,22 @@ static int proc_readfd_common(struct file * filp, void * dirent,
                              fd++, filp->f_pos++) {
                                 char name[PROC_NUMBUF];
                                 int len;
+                                int rv;
 
                                 if (!fcheck_files(files, fd))
                                         continue;
                                 rcu_read_unlock();
 
                                 len = snprintf(name, sizeof(name), "%d", fd);
-                                if (proc_fill_cache(filp, dirent, filldir,
-                                                    name, len, instantiate,
-                                                    p, &fd) < 0) {
-                                        rcu_read_lock();
-                                        break;
-                                }
+                                rv = proc_fill_cache(filp, dirent, filldir,
+                                                     name, len, instantiate, p,
+                                                     &fd);
+                                if (rv < 0)
+                                        goto out_fd_loop;
                                 rcu_read_lock();
                         }
                         rcu_read_unlock();
+out_fd_loop:
                         put_files_struct(files);
         }
 out: