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Message-ID: <20080220204756.1aa67aee@core>
Date: Wed, 20 Feb 2008 20:47:56 +0000
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: akpm@...l.org, linux-kernel@...r.kernel.org, greg@...ah.com
Subject: [PATCH] usb-serial: Prepare for BKL push down
Take the lock in usb-serial instead. As it relies on the BKL internally
we can't push it any deeper yet.
Signed-off-by: Alan Cox <alan@...hat.com>
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.25-rc2-mm1/drivers/usb/serial/usb-serial.c linux-2.6.25-rc2-mm1/drivers/usb/serial/usb-serial.c
--- linux.vanilla-2.6.25-rc2-mm1/drivers/usb/serial/usb-serial.c 2008-02-19 11:03:01.000000000 +0000
+++ linux-2.6.25-rc2-mm1/drivers/usb/serial/usb-serial.c 2008-02-20 11:53:06.000000000 +0000
@@ -401,11 +401,13 @@
struct usb_serial_port *port = tty->driver_data;
int retval = -ENODEV;
+ lock_kernel();
if (!port)
goto exit;
dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);
+ /* Caution - port->open_count is BKL protected */
if (!port->open_count) {
dbg ("%s - port not open", __FUNCTION__);
goto exit;
@@ -416,8 +418,8 @@
retval = port->serial->type->ioctl(port, file, cmd, arg);
else
retval = -ENOIOCTLCMD;
-
exit:
+ unlock_kernel();
return retval;
}
@@ -446,19 +448,24 @@
{
struct usb_serial_port *port = tty->driver_data;
- if (!port)
+ lock_kernel();
+ if (!port) {
+ unlock_kernel();
return;
+ }
dbg("%s - port %d", __FUNCTION__, port->number);
if (!port->open_count) {
dbg("%s - port not open", __FUNCTION__);
+ unlock_kernel();
return;
}
/* pass on to the driver specific version of this function if it is available */
if (port->serial->type->break_ctl)
port->serial->type->break_ctl(port, break_state);
+ unlock_kernel();
}
static int serial_read_proc (char *page, char **start, off_t off, int count, int *eof, void *data)
--
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