[PATCH 5.15 050/247] tty: n_gsm: Dont ignore write return value in gsmld_output()

[Greg Kroah-Hartman]

From: Tony Lindgren <tony@xxxxxxxxxxx>

[ Upstream commit 9136c68346d096697935b9840782f7051d5796c5 ]

We currently have gsmld_output() ignore the return value from device
write. This means we will lose packets if device write returns 0 or
an error.

Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210930060624.46523-1-tony@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/tty/n_gsm.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 1767503de744..0722860b6f54 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -692,7 +692,7 @@ static void gsm_data_kick(struct gsm_mux *gsm, struct gsm_dlci *dlci)
 			print_hex_dump_bytes("gsm_data_kick: ",
 					     DUMP_PREFIX_OFFSET,
 					     gsm->txframe, len);
-		if (gsmld_output(gsm, gsm->txframe, len) < 0)
+		if (gsmld_output(gsm, gsm->txframe, len) <= 0)
 			break;
 		/* FIXME: Can eliminate one SOF in many more cases */
 		gsm->tx_bytes -= msg->len;
@@ -2373,8 +2373,7 @@ static int gsmld_output(struct gsm_mux *gsm, u8 *data, int len)
 	if (debug & 4)
 		print_hex_dump_bytes("gsmld_output: ", DUMP_PREFIX_OFFSET,
 				     data, len);
-	gsm->tty->ops->write(gsm->tty, data, len);
-	return len;
+	return gsm->tty->ops->write(gsm->tty, data, len);
 }
 
 /**
-- 
2.35.1