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From:   Tony Lindgren <tony@atomide.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Gregory CLEMENT <gregory.clement@bootlin.com>,
        Jiri Slaby <jirislaby@kernel.org>,
        Johan Hovold <johan@kernel.org>, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] tty: n_gsm: Don't ignore write return value in gsmld_output()
Date:   Thu, 30 Sep 2021 09:06:24 +0300
Message-Id: <20210930060624.46523-1-tony@atomide.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@atomide.com>
---
 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
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -687,7 +687,7 @@ 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;
@@ -2358,8 +2358,7 @@ 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);
 }
 
 /**
-- 
2.33.0