[PATCH 3/17] arch/mips/kernel: Add missing read_unlock

[Julia Lawall <julia@diku.dk>]

From: Julia Lawall <julia@diku.dk>

Add a read_unlock missing on the error path.  Other ways of reaching
out_unlock have tasklist_lock unlocked.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* read_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* read_unlock(E1,...);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
I wasn't able to find what security_task_setscheduler actually does.  
If it releases tasklist_lock in an error case, then ignire this patch.

 arch/mips/kernel/mips-mt-fpaff.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c
index f5981c4..73581bf 100644
--- a/arch/mips/kernel/mips-mt-fpaff.c
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -86,8 +86,10 @@ asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
 	}
 
 	retval = security_task_setscheduler(p, 0, NULL);
-	if (retval)
+	if (retval) {
+		read_unlock(&tasklist_lock);
 		goto out_unlock;
+	}
 
 	/* Record new user-specified CPU set for future reference */
 	p->thread.user_cpus_allowed = new_mask;