From: Zhenguo Zhao <Zhenguo.Zhao1@xxxxxxxxxx> [ Upstream commit 0b91b5332368f2fb0c3e5cfebc6aff9e167acd8b ] When n_gsm config "initiator=0",as requester ,receive SABM frame,n_gsm register gsmtty dev,and save dlci open address status,if receive DLC0 DISC or CLD frame,it can unregister the gsmtty dev by saving dlci address. Signed-off-by: Zhenguo Zhao <Zhenguo.Zhao1@xxxxxxxxxx> Link: https://lore.kernel.org/r/1629461872-26965-8-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 | 57 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 53 insertions(+), 4 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 91ce8e6e889a..3038e5631be5 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -274,6 +274,10 @@ static DEFINE_SPINLOCK(gsm_mux_lock); static struct tty_driver *gsm_tty_driver; +/* Save dlci open address */ +static int addr_open[256] = { 0 }; +/* Save dlci open count */ +static int addr_cnt; /* * This section of the driver logic implements the GSM encodings * both the basic and the 'advanced'. Reliable transport is not @@ -1191,6 +1195,7 @@ static void gsm_control_rls(struct gsm_mux *gsm, const u8 *data, int clen) } static void gsm_dlci_begin_close(struct gsm_dlci *dlci); +static void gsm_dlci_close(struct gsm_dlci *dlci); /** * gsm_control_message - DLCI 0 control processing @@ -1209,15 +1214,28 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, { u8 buf[1]; unsigned long flags; + struct gsm_dlci *dlci; + int i; + int address; switch (command) { case CMD_CLD: { - struct gsm_dlci *dlci = gsm->dlci[0]; + if (addr_cnt > 0) { + for (i = 0; i < addr_cnt; i++) { + address = addr_open[i]; + dlci = gsm->dlci[address]; + gsm_dlci_close(dlci); + addr_open[i] = 0; + } + } /* Modem wishes to close down */ + dlci = gsm->dlci[0]; if (dlci) { dlci->dead = true; gsm->dead = true; - gsm_dlci_begin_close(dlci); + gsm_dlci_close(dlci); + addr_cnt = 0; + gsm_response(gsm, 0, UA|PF); } } break; @@ -1780,6 +1798,7 @@ static void gsm_queue(struct gsm_mux *gsm) struct gsm_dlci *dlci; u8 cr; int address; + int i, j, k, address_tmp; /* We have to sneak a look at the packet body to do the FCS. A somewhat layering violation in the spec */ @@ -1822,6 +1841,11 @@ static void gsm_queue(struct gsm_mux *gsm) else { gsm_response(gsm, address, UA|PF); gsm_dlci_open(dlci); + /* Save dlci open address */ + if (address) { + addr_open[addr_cnt] = address; + addr_cnt++; + } } break; case DISC|PF: @@ -1832,8 +1856,33 @@ static void gsm_queue(struct gsm_mux *gsm) return; } /* Real close complete */ - gsm_response(gsm, address, UA|PF); - gsm_dlci_close(dlci); + if (!address) { + if (addr_cnt > 0) { + for (i = 0; i < addr_cnt; i++) { + address = addr_open[i]; + dlci = gsm->dlci[address]; + gsm_dlci_close(dlci); + addr_open[i] = 0; + } + } + dlci = gsm->dlci[0]; + gsm_dlci_close(dlci); + addr_cnt = 0; + gsm_response(gsm, 0, UA|PF); + } else { + gsm_response(gsm, address, UA|PF); + gsm_dlci_close(dlci); + /* clear dlci address */ + for (j = 0; j < addr_cnt; j++) { + address_tmp = addr_open[j]; + if (address_tmp == address) { + for (k = j; k < addr_cnt; k++) + addr_open[k] = addr_open[k+1]; + addr_cnt--; + break; + } + } + } break; case UA|PF: if (cr == 0 || dlci == NULL) -- 2.35.1
