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Date: Fri, 1 Jan 2021 11:37:18 +0800
From: Gao Yan <gao.yanB@....com>
To: <gregkh@...uxfoundation.org>, <jirislaby@...nel.org>,
<paulus@...ba.org>, <davem@...emloft.net>, <kuba@...nel.org>,
<linux-kernel@...r.kernel.org>
CC: Gao Yan <gao.yanB@....com>
Subject: [PATCH] [v2]net:ppp: remove disc_data_lock in ppp line discipline
In tty layer, it provides tty->ldisc_sem to protect all tty_ldisc_ops
including ppp_sync_ldisc. So I think tty->ldisc_sem can also
protect tty->disc_data, and the disc_data_lock is not necessary.
Signed-off-by: Gao Yan <gao.yanB@....com>
---
drivers/net/ppp/ppp_async.c | 11 ++---------
drivers/net/ppp/ppp_synctty.c | 12 ++----------
2 files changed, 4 insertions(+), 19 deletions(-)
diff --git a/drivers/net/ppp/ppp_async.c b/drivers/net/ppp/ppp_async.c
index 29a0917a8..20b50facd 100644
--- a/drivers/net/ppp/ppp_async.c
+++ b/drivers/net/ppp/ppp_async.c
@@ -127,17 +127,13 @@ static const struct ppp_channel_ops async_ops = {
* FIXME: this is no longer true. The _close path for the ldisc is
* now guaranteed to be sane.
*/
-static DEFINE_RWLOCK(disc_data_lock);
static struct asyncppp *ap_get(struct tty_struct *tty)
{
- struct asyncppp *ap;
+ struct asyncppp *ap = tty->disc_data;
- read_lock(&disc_data_lock);
- ap = tty->disc_data;
if (ap != NULL)
refcount_inc(&ap->refcnt);
- read_unlock(&disc_data_lock);
return ap;
}
@@ -214,12 +210,9 @@ ppp_asynctty_open(struct tty_struct *tty)
static void
ppp_asynctty_close(struct tty_struct *tty)
{
- struct asyncppp *ap;
+ struct asyncppp *ap = tty->disc_data;
- write_lock_irq(&disc_data_lock);
- ap = tty->disc_data;
tty->disc_data = NULL;
- write_unlock_irq(&disc_data_lock);
if (!ap)
return;
diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c
index 0f338752c..53fb68e29 100644
--- a/drivers/net/ppp/ppp_synctty.c
+++ b/drivers/net/ppp/ppp_synctty.c
@@ -129,17 +129,12 @@ ppp_print_buffer (const char *name, const __u8 *buf, int count)
*
* FIXME: Fixed in tty_io nowadays.
*/
-static DEFINE_RWLOCK(disc_data_lock);
-
static struct syncppp *sp_get(struct tty_struct *tty)
{
- struct syncppp *ap;
+ struct syncppp *ap = tty->disc_data;
- read_lock(&disc_data_lock);
- ap = tty->disc_data;
if (ap != NULL)
refcount_inc(&ap->refcnt);
- read_unlock(&disc_data_lock);
return ap;
}
@@ -213,12 +208,9 @@ ppp_sync_open(struct tty_struct *tty)
static void
ppp_sync_close(struct tty_struct *tty)
{
- struct syncppp *ap;
+ struct syncppp *ap = tty->disc_data;
- write_lock_irq(&disc_data_lock);
- ap = tty->disc_data;
tty->disc_data = NULL;
- write_unlock_irq(&disc_data_lock);
if (!ap)
return;
--
2.17.1
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