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 <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 155dee600ed460278a93c6f0c79dba9231c2f3fc..0f928cbba4a4ca192aac47fb9b404fb9451f274a 100644 (file)
--- 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: