>From 8c6c632cf61f671f4fb793b511745a04b365ff1f Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@xxxxxxxxxx>
Date: Thu, 14 Jan 2010 10:03:56 +0100
Subject: [PATCH 06/13] usb:BKL removal:rio500
This driver had used BKL to guard against disconnect but
was incorrectly converted leaving an SMP race.
BKL was added to disconnect() to fix this race
BKL was removed from ioctl() as the mutex is sufficient
on its own.
Signed-off-by: Oliver Neukum <oliver@xxxxxxxxxx>
---
drivers/usb/misc/rio500.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/misc/rio500.c b/drivers/usb/misc/rio500.c
index 13bb628..f92a691 100644
--- a/drivers/usb/misc/rio500.c
+++ b/drivers/usb/misc/rio500.c
@@ -77,11 +77,14 @@ static struct rio_usb_data rio_instance;
static int open_rio(struct inode *inode, struct file *file)
{
struct rio_usb_data *rio = &rio_instance;
+
+ /* against disconnect() */
lock_kernel();
mutex_lock(&(rio->lock));
if (rio->isopen || !rio->present) {
mutex_unlock(&(rio->lock));
+ unlock_kernel();
return -EBUSY;
}
rio->isopen = 1;
@@ -116,7 +119,6 @@ static long ioctl_rio(struct file *file, unsigned int cmd, unsigned long arg)
int retries;
int retval=0;
- lock_kernel();
mutex_lock(&(rio->lock));
/* Sanity check to make sure rio is connected, powered, etc */
if (rio->present == 0 || rio->rio_dev == NULL) {
@@ -255,7 +257,6 @@ static long ioctl_rio(struct file *file, unsigned int cmd, unsigned long arg)
err_out:
mutex_unlock(&(rio->lock));
- unlock_kernel();
return retval;
}
@@ -490,6 +491,7 @@ static void disconnect_rio(struct usb_interface *intf)
struct rio_usb_data *rio = usb_get_intfdata (intf);
usb_set_intfdata (intf, NULL);
+ lock_kernel();
if (rio) {
usb_deregister_dev(intf, &usb_rio_class);
@@ -499,6 +501,7 @@ static void disconnect_rio(struct usb_interface *intf)
/* better let it finish - the release will do whats needed */
rio->rio_dev = NULL;
mutex_unlock(&(rio->lock));
+ unlock_kernel();
return;
}
kfree(rio->ibuf);
@@ -509,6 +512,7 @@ static void disconnect_rio(struct usb_interface *intf)
rio->present = 0;
mutex_unlock(&(rio->lock));
}
+ unlock_kernel();
}
static struct usb_device_id rio_table [] = {
--
1.6.4.2
--
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