From: Zhenguo Zhao <Zhenguo.Zhao1@xxxxxxxxxx> [ Upstream commit cc0f42122a7e7a5ede9c5f2a41199128b8449eda ] When n_gsm config "initiator=0",as requester,gsmld receives dlci SABM/DISC control command frame,but send UA frame is error. Example: Gsmld receive dlc0 SABM frame "f9 03 3f 01 1c f9",now it sends UA frame "f9 01 63 01 a3 f9",CR and PF bit are 0,but it should be set 1 from requster to initiator. Kernel test log as follows: Before modify [ 271.732031] c1 gsmld_receive: 00000000: f9 03 3f 01 1c f9 [ 271.741719] c1 <-- 0) C: SABM(P) [ 271.749483] c1 gsmld_output: 00000000: f9 01 63 01 a3 f9 [ 271.758337] c1 --> 0) R: UA(F) After modify [ 261.233188] c0 gsmld_receive: 00000000: f9 03 3f 01 1c f9 [ 261.242767] c0 <-- 0) C: SABM(P) [ 261.250497] c0 gsmld_output: 00000000: f9 03 73 01 d7 f9 [ 261.259759] c0 --> 0) C: UA(P) Signed-off-by: Zhenguo Zhao <Zhenguo.Zhao1@xxxxxxxxxx> Link: https://lore.kernel.org/r/1629461872-26965-3-git-send-email-zhenguo6858@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/n_gsm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 6734ef22c304..91ce8e6e889a 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -625,7 +625,7 @@ static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control) static inline void gsm_response(struct gsm_mux *gsm, int addr, int control) { - gsm_send(gsm, addr, 0, control); + gsm_send(gsm, addr, 1, control); } /** @@ -1818,9 +1818,9 @@ static void gsm_queue(struct gsm_mux *gsm) if (dlci == NULL) return; if (dlci->dead) - gsm_response(gsm, address, DM); + gsm_response(gsm, address, DM|PF); else { - gsm_response(gsm, address, UA); + gsm_response(gsm, address, UA|PF); gsm_dlci_open(dlci); } break; @@ -1828,11 +1828,11 @@ static void gsm_queue(struct gsm_mux *gsm) if (cr == 0) goto invalid; if (dlci == NULL || dlci->state == DLCI_CLOSED) { - gsm_response(gsm, address, DM); + gsm_response(gsm, address, DM|PF); return; } /* Real close complete */ - gsm_response(gsm, address, UA); + gsm_response(gsm, address, UA|PF); gsm_dlci_close(dlci); break; case UA|PF: -- 2.35.1
