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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hillf Danton <hdanton@sina.com>,
        =?UTF-8?q?=E4=B8=80=E5=8F=AA=E7=8B=97?= <chennbnbnb@gmail.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Jiri Slaby <jslaby@suse.cz>
Subject: [PATCH 4.9 24/26] tty: extract tty_flip_buffer_commit() from tty_flip_buffer_push()
Date:   Wed, 27 Jul 2022 18:10:53 +0200
Message-Id: <20220727161000.083152864@linuxfoundation.org>
In-Reply-To: <20220727160959.122591422@linuxfoundation.org>
References: <20220727160959.122591422@linuxfoundation.org>
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From: Jiri Slaby <jslaby@suse.cz>

commit 716b10580283fda66f2b88140e3964f8a7f9da89 upstream.

We will need this new helper in the next patch.

Cc: Hillf Danton <hdanton@sina.com>
Cc: 一只狗 <chennbnbnb@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220707082558.9250-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/tty_buffer.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -526,6 +526,15 @@ static void flush_to_ldisc(struct work_s
 	tty_ldisc_deref(disc);
 }
 
+static inline void tty_flip_buffer_commit(struct tty_buffer *tail)
+{
+	/*
+	 * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees
+	 * buffer data.
+	 */
+	smp_store_release(&tail->commit, tail->used);
+}
+
 /**
  *	tty_flip_buffer_push	-	terminal
  *	@port: tty port to push
@@ -541,11 +550,7 @@ void tty_flip_buffer_push(struct tty_por
 {
 	struct tty_bufhead *buf = &port->buf;
 
-	/*
-	 * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees
-	 * buffer data.
-	 */
-	smp_store_release(&buf->tail->commit, buf->tail->used);
+	tty_flip_buffer_commit(buf->tail);
 	queue_work(system_unbound_wq, &buf->work);
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);