From 59ff0680ecbfec742b1e0381e7cc46b41eb06647 Mon Sep 17 00:00:00 2001 From: Daniel Starke Date: Thu, 7 Jul 2022 13:32:22 +0200 Subject: [PATCH] tty: n_gsm: fix flow control handling in tx path The current implementation constipates all transmission paths during flow control except for flow control frames. However, these may not be located at the beginning of the transmission queue of the control channel. Ensure that flow control frames in the transmission queue for the control channel are always handled even if constipated by skipping through other messages. Fixes: 0af021678d5d ("tty: n_gsm: fix deadlock and link starvation in outgoing data path") Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220707113223.3685-3-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 9006001..51447cc 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -891,7 +891,7 @@ static int gsm_data_kick(struct gsm_mux *gsm) /* Serialize control messages and control channel messages first */ list_for_each_entry_safe(msg, nmsg, &gsm->tx_ctrl_list, list) { if (gsm->constipated && !gsm_is_flow_ctrl_msg(msg)) - return -EAGAIN; + continue; ret = gsm_send_packet(gsm, msg); switch (ret) { case -ENOSPC: -- 2.7.4