[PATCH 1/2] proc: don't do dummy rcu_read_lock/rcu_read_unlock onerror path

From: Alexey Dobriyan
Date: Sat Apr 07 2012 - 15:03:11 EST


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@xxxxxxxxx>
---

fs/proc/base.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1943,21 +1943,22 @@ 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:
--
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