From 2ee0826085d1c0281cb60c1f4bc3e0c27efeedc3 Mon Sep 17 00:00:00 2001
From: Mike Rapoport <rppt@linux.vnet.ibm.com>
Date: Tue, 6 Feb 2018 15:40:17 -0800
Subject: pids: introduce find_get_task_by_vpid() helper

There are several functions that do find_task_by_vpid() followed by
get_task_struct().  We can use a helper function instead.

Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/ia64/kernel/perfmon.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

(limited to 'arch/ia64')

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index c44f002e8f6b..858602494096 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2610,17 +2610,10 @@ pfm_get_task(pfm_context_t *ctx, pid_t pid, struct task_struct **task)
 	if (pid < 2) return -EPERM;
 
 	if (pid != task_pid_vnr(current)) {
-
-		read_lock(&tasklist_lock);
-
-		p = find_task_by_vpid(pid);
-
 		/* make sure task cannot go away while we operate on it */
-		if (p) get_task_struct(p);
-
-		read_unlock(&tasklist_lock);
-
-		if (p == NULL) return -ESRCH;
+		p = find_get_task_by_vpid(pid);
+		if (!p)
+			return -ESRCH;
 	}
 
 	ret = pfm_task_incompatible(ctx, p);
-- 
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