USB: ftdi_sio: Replace BKL with a mutex
As Alan Cox have pinpointed the driver still required protection against
parallels calls to the config ioctl(). If lock is still necessary the use of
BKL is abused here. So replace BKL with a more convenient mutex.
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index dd5bfbc..8261299 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -33,12 +33,12 @@
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
-#include <linux/smp_lock.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
+#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/serial.h>
@@ -92,6 +92,7 @@
unsigned long tx_outstanding_bytes;
unsigned long tx_outstanding_urbs;
unsigned short max_packet_size;
+ struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() */
};
/* struct ftdi_sio_quirk is used by devices requiring special attention. */
@@ -1218,7 +1219,7 @@
if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
return -EFAULT;
- lock_kernel();
+ mutex_lock(&priv->cfg_lock);
old_priv = *priv;
/* Do error checking and permission checking */
@@ -1226,7 +1227,7 @@
if (!capable(CAP_SYS_ADMIN)) {
if (((new_serial.flags & ~ASYNC_USR_MASK) !=
(priv->flags & ~ASYNC_USR_MASK))) {
- unlock_kernel();
+ mutex_unlock(&priv->cfg_lock);
return -EPERM;
}
priv->flags = ((priv->flags & ~ASYNC_USR_MASK) |
@@ -1237,7 +1238,7 @@
if ((new_serial.baud_base != priv->baud_base) &&
(new_serial.baud_base < 9600)) {
- unlock_kernel();
+ mutex_unlock(&priv->cfg_lock);
return -EINVAL;
}
@@ -1267,11 +1268,11 @@
(priv->flags & ASYNC_SPD_MASK)) ||
(((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
(old_priv.custom_divisor != priv->custom_divisor))) {
- unlock_kernel();
+ mutex_unlock(&priv->cfg_lock);
change_speed(tty, port);
}
else
- unlock_kernel();
+ mutex_unlock(&priv->cfg_lock);
return 0;
} /* set_serial_info */
@@ -1538,6 +1539,7 @@
kref_init(&priv->kref);
spin_lock_init(&priv->tx_lock);
+ mutex_init(&priv->cfg_lock);
init_waitqueue_head(&priv->delta_msr_wait);
priv->flags = ASYNC_LOW_LATENCY;
