From: Gregory CLEMENT gregory.clement@bootlin.com
[ Upstream commit 01dbb362f0a114fbce19c8abe4cd6f4710e934d5 ]
Warn the upper layer when n_gms is ready to receive data again. Without this the associated virtual tty remains blocked indefinitely.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Gregory CLEMENT gregory.clement@bootlin.com Link: https://lore.kernel.org/r/20200512115323.1447922-4-gregory.clement@bootlin.c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/tty/n_gsm.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 8d8229dd2796..166052002b79 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -665,7 +665,7 @@ static struct gsm_msg *gsm_data_alloc(struct gsm_mux *gsm, u8 addr, int len, * FIXME: lock against link layer control transmissions */
-static void gsm_data_kick(struct gsm_mux *gsm) +static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci) { struct gsm_msg *msg, *nmsg; int len; @@ -697,6 +697,24 @@ static void gsm_data_kick(struct gsm_mux *gsm)
list_del(&msg->list); kfree(msg); + + if (dlci) { + tty_port_tty_wakeup(&dlci->port); + } else { + int i = 0; + + for (i = 0; i < NUM_DLCI; i++) { + struct gsm_dlci *dlci; + + dlci = gsm->dlci[i]; + if (dlci == NULL) { + i++; + continue; + } + + tty_port_tty_wakeup(&dlci->port); + } + } } }
@@ -748,7 +766,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) /* Add to the actual output queue */ list_add_tail(&msg->list, &gsm->tx_list); gsm->tx_bytes += msg->len; - gsm_data_kick(gsm); + gsm_data_kick(gsm, dlci); }
/** @@ -1209,7 +1227,7 @@ static void gsm_control_message(struct gsm_mux *gsm, unsigned int command, gsm_control_reply(gsm, CMD_FCON, NULL, 0); /* Kick the link in case it is idling */ spin_lock_irqsave(&gsm->tx_lock, flags); - gsm_data_kick(gsm); + gsm_data_kick(gsm, NULL); spin_unlock_irqrestore(&gsm->tx_lock, flags); break; case CMD_FCOFF: @@ -2406,7 +2424,7 @@ static void gsmld_write_wakeup(struct tty_struct *tty) /* Queue poll */ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); spin_lock_irqsave(&gsm->tx_lock, flags); - gsm_data_kick(gsm); + gsm_data_kick(gsm, NULL); if (gsm->tx_bytes < TX_THRESH_LO) { gsm_dlci_data_sweep(gsm); }