Clean up the kill_something_info

This is the first step (of two) in removing the kill_pgrp_info.

All the users of this function are in kernel/signal.c, but all they need is to
call __kill_pgrp_info() with the tasklist_lock read-locked.

Fortunately, one of its users is the kill_something_info(), which already
needs this lock in one of its branches, so clean these branches up and call
the __kill_pgrp_info() directly.

Based on Oleg's view of how this function should look.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 11 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index cc45a6b6913..a805c7417cd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1134,14 +1134,22 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
 static int kill_something_info(int sig, struct siginfo *info, int pid)
 {
         int ret;
-        rcu_read_lock();
-        if (!pid) {
-                ret = kill_pgrp_info(sig, info, task_pgrp(current));
-        } else if (pid == -1) {
+
+        if (pid > 0) {
+                rcu_read_lock();
+                ret = kill_pid_info(sig, info, find_vpid(pid));
+                rcu_read_unlock();
+                return ret;
+        }
+
+        read_lock(&tasklist_lock);
+        if (pid != -1) {
+                ret = __kill_pgrp_info(sig, info,
+                                pid ? find_vpid(-pid) : task_pgrp(current));
+        } else {
                 int retval = 0, count = 0;
                 struct task_struct * p;
 
-                read_lock(&tasklist_lock);
                 for_each_process(p) {
                         if (p->pid > 1 && !same_thread_group(p, current)) {
                                 int err = group_send_sig_info(sig, info, p);
@@ -1150,14 +1158,10 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
                                         retval = err;
                         }
                 }
-                read_unlock(&tasklist_lock);
                 ret = count ? retval : -ESRCH;
-        } else if (pid < 0) {
-                ret = kill_pgrp_info(sig, info, find_vpid(-pid));
-        } else {
-                ret = kill_pid_info(sig, info, find_vpid(pid));
         }
-        rcu_read_unlock();
+        read_unlock(&tasklist_lock);
+
         return ret;
 }