This is a note to let you know that I've just added the patch titled USB: serial: ftdi_sio: clean up receive processing to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-serial-ftdi_sio-clean-up-receive-processing.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit df07cb0b0ae6e2f6b03767114f2dfe2ed674b6e4 Author: Johan Hovold <johan@xxxxxxxxxx> Date: Wed Jul 8 14:49:52 2020 +0200 USB: serial: ftdi_sio: clean up receive processing [ Upstream commit ce054039ba5e47b75a3be02a00274e52b06a6456 ] Clean up receive processing by dropping the character pointer and keeping the length argument unchanged throughout the function. Also make it more apparent that sysrq processing can consume a characters by adding an explicit continue. Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 2583d21382b06..0c8b24ff44a05 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -2054,7 +2054,6 @@ static int ftdi_process_packet(struct usb_serial_port *port, struct ftdi_private *priv, unsigned char *buf, int len) { unsigned char status; - unsigned char *ch; int i; char flag; @@ -2097,8 +2096,7 @@ static int ftdi_process_packet(struct usb_serial_port *port, else priv->transmit_empty = 0; - len -= 2; - if (!len) + if (len == 2) return 0; /* status only */ /* @@ -2127,19 +2125,20 @@ static int ftdi_process_packet(struct usb_serial_port *port, } } - port->icount.rx += len; - ch = buf + 2; + port->icount.rx += len - 2; if (port->port.console && port->sysrq) { - for (i = 0; i < len; i++, ch++) { - if (!usb_serial_handle_sysrq_char(port, *ch)) - tty_insert_flip_char(&port->port, *ch, flag); + for (i = 2; i < len; i++) { + if (usb_serial_handle_sysrq_char(port, buf[i])) + continue; + tty_insert_flip_char(&port->port, buf[i], flag); } } else { - tty_insert_flip_string_fixed_flag(&port->port, ch, flag, len); + tty_insert_flip_string_fixed_flag(&port->port, buf + 2, flag, + len - 2); } - return len; + return len - 2; } static void ftdi_process_read_urb(struct urb *urb)