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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jiri Slaby <jslaby@suse.cz>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0590/1039] mxser: increase buf_overrun if tty_insert_flip_char() fails
Date:   Mon, 24 Jan 2022 19:39:39 +0100
Message-Id: <20220124184145.165420298@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
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From: Jiri Slaby <jslaby@suse.cz>

[ Upstream commit eb68ac0462bffc2ceb63b3a76737d6c9f186e6de ]

mxser doesn't increase port->icount.buf_overrun at all. Do so if overrun
happens, so that it can be read from the stats.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-17-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/mxser.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 3b5d193b7f245..39458b42df7b0 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -1536,7 +1536,8 @@ static bool mxser_receive_chars_new(struct tty_struct *tty,
 
 	while (gdl--) {
 		u8 ch = inb(port->ioaddr + UART_RX);
-		tty_insert_flip_char(&port->port, ch, 0);
+		if (!tty_insert_flip_char(&port->port, ch, 0))
+			port->icount.buf_overrun++;
 	}
 
 	return true;
@@ -1582,8 +1583,10 @@ static u8 mxser_receive_chars_old(struct tty_struct *tty,
 					port->icount.overrun++;
 				}
 			}
-			if (!tty_insert_flip_char(&port->port, ch, flag))
+			if (!tty_insert_flip_char(&port->port, ch, flag)) {
+				port->icount.buf_overrun++;
 				break;
+			}
 		}
 
 		if (hwid)
-- 
2.34.1