linux-kernel - [PATCH 2/4] proc: change first_tid() to use while_each_thread() rather than next

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Message-ID: <20131120183024.GA12212@redhat.com>
Date:	Wed, 20 Nov 2013 19:30:24 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Michal Hocko <mhocko@...e.cz>, Sameer Nanda <snanda@...omium.org>,
	Sergey Dyasly <dserrg@...il.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/4] proc: change first_tid() to use while_each_thread()
	rather than next_thread()

Rerwrite the main loop to use while_each_thread() instead of
next_thread(). We are going to fix or replace while_each_thread(),
next_thread() should be avoided whenever possible.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 fs/proc/base.c |   20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index da12c5c..7ab3785 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3100,23 +3100,23 @@ static struct task_struct *first_tid(struct task_struct *leader,
 	}
 
 	/* If nr exceeds the number of threads there is nothing todo */
-	pos = NULL;
 	if (nr && nr >= get_nr_threads(leader))
-		goto out;
+		goto fail;
 	/* It could be unhashed before we take rcu lock */
 	if (!pid_alive(leader))
-		goto out;
+		goto fail;
 
 	/* If we haven't found our starting place yet start
 	 * with the leader and walk nr threads forward.
 	 */
-	for (pos = leader; nr > 0; --nr) {
-		pos = next_thread(pos);
-		if (pos == leader) {
-			pos = NULL;
-			goto out;
-		}
-	}
+	pos = leader;
+	do {
+		if (nr-- <= 0)
+			goto found;
+	} while_each_thread(leader, pos);
+fail:
+	pos = NULL;
+	goto out;
 found:
 	get_task_struct(pos);
 out:
-- 
1.5.5.1

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