USB: cdc-acm: fix close_delay and closing_wait units in TIOCSSERIAL

BugLink: https://bugs.launchpad.net/bugs/1873852

[ Upstream commit 633e2b2d ]

close_delay and closing_wait are specified in hundredth of a second but stored
internally in jiffies. Use the jiffies_to_msecs() and msecs_to_jiffies()
functions to convert from each other.
Signed-off-by: Anthony Mallet <anthony.mallet@laas.fr>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200312133101.7096-1-anthony.mallet@laas.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

drivers/usb/class/cdc-acm.c

@@ -841,10 +841,10 @@ static int get_serial_info(struct acm *acm, struct serial_struct __user *info)
 	tmp.flags = ASYNC_LOW_LATENCY;
 	tmp.xmit_fifo_size = acm->writesize;
 	tmp.baud_base = le32_to_cpu(acm->line.dwDTERate);
-	tmp.close_delay	= acm->port.close_delay / 10;
+	tmp.close_delay	= jiffies_to_msecs(acm->port.close_delay) / 10;
 	tmp.closing_wait = acm->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 				ASYNC_CLOSING_WAIT_NONE :
-				acm->port.closing_wait / 10;
+				jiffies_to_msecs(acm->port.closing_wait) / 10;
 
 	if (copy_to_user(info, &tmp, sizeof(tmp)))
 		return -EFAULT;
@@ -862,9 +862,10 @@ static int set_serial_info(struct acm *acm,
 	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
 		return -EFAULT;
 
-	close_delay = new_serial.close_delay * 10;
+	close_delay = msecs_to_jiffies(new_serial.close_delay * 10);
 	closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
-			ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
+			ASYNC_CLOSING_WAIT_NONE :
+			msecs_to_jiffies(new_serial.closing_wait * 10);
 
 	mutex_lock(&acm->port.mutex);