From: Zhenguo Zhao <Zhenguo.Zhao1@unisoc.com> stable inclusion from stable-v5.10.137 commit 9e38020f17009c53b0f28347ec06102929b8962c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit cbff2b32516881bef30bbebf413d1b49495bab1d ] When n_gsm config "initiator=0",as requester ,it doesn't need to send SABM frame data during gsmtty open. Example,when gsmtty open,it will send SABM frame.for initiator,it maybe not want to receive the frame. [ 88.410426] c1 gsmld_output: 00000000: f9 07 3f 01 de f9 [ 88.420839] c1 --> 1) R: SABM(F) Signed-off-by: Zhenguo Zhao <Zhenguo.Zhao1@unisoc.com> Link: https://lore.kernel.org/r/1629461872-26965-6-git-send-email-zhenguo6858@gmai... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/tty/n_gsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index b05b7862778c..405b55bceba8 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3024,6 +3024,7 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp) { struct gsm_dlci *dlci = tty->driver_data; struct tty_port *port = &dlci->port; + struct gsm_mux *gsm = dlci->gsm; port->count++; tty_port_tty_set(port, tty); @@ -3033,7 +3034,8 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp) a DM straight back. This is ok as that will have caused a hangup */ tty_port_set_initialized(port, 1); /* Start sending off SABM messages */ - gsm_dlci_begin_open(dlci); + if (gsm->initiator) + gsm_dlci_begin_open(dlci); /* And wait for virtual carrier */ return tty_port_block_til_ready(port, tty, filp); } -- 2.20.1