From a7eaaa9d1032e68669bb479496087ba8fc155ab6 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 7 Apr 2021 12:23:21 +0200
Subject: [PATCH] staging: fwserial: fix TIOCSSERIAL implementation
Git-commit: a7eaaa9d1032e68669bb479496087ba8fc155ab6
Patch-mainline: v5.13-rc1
References: git-fixes

TIOCSSERIAL is a horrid, underspecified, legacy interface which for most
serial devices is only useful for setting the close_delay and
closing_wait parameters.

A non-privileged user has only ever been able to set the since long
deprecated ASYNC_SPD flags and trying to change any other *supported*
feature should result in -EPERM being returned. Setting the current
values for any supported features should return success.

Fix the fwserial implementation which was returning -EPERM also for a
privileged user when trying to change certain unsupported parameters,
and instead return success consistently.

Fixes: 7355ba3445f2 ("staging: fwserial: Add TTY-over-Firewire serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407102334.32361-4-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/staging/fwserial/fwserial.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/staging/fwserial/fwserial.c b/drivers/staging/fwserial/fwserial.c
index 440d11423812..2888b80a2c1a 100644
--- a/drivers/staging/fwserial/fwserial.c
+++ b/drivers/staging/fwserial/fwserial.c
@@ -1234,10 +1234,6 @@ static int set_serial_info(struct tty_struct *tty,
 	struct fwtty_port *port = tty->driver_data;
 	unsigned int cdelay;
 
-	if (ss->irq != 0 || ss->port != 0 || ss->custom_divisor != 0 ||
-	    ss->baud_base != 400000000)
-		return -EPERM;
-
 	cdelay = msecs_to_jiffies(ss->close_delay * 10);
 
 	mutex_lock(&port->port.mutex);
-- 
2.26.2