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Commit eb33caec authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Greg Kroah-Hartman
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USB: use mutex instead of semaphore in the FTDI ELAN driver 



The FTDI ELAN driver uses a semaphore as mutex. Use the mutex API
instead of the (binary) semaphore.

Signed-off-by: default avatarMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 8293c568

drivers/usb/misc/ftdi-elan.c

+7 −6
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <linux/slab.h>

#include <linux/module.h>

#include <linux/kref.h>

#include <linux/mutex.h>

#include <asm/uaccess.h>

#include <linux/usb.h>

#include <linux/workqueue.h>
@@ -64,7 +65,7 @@ static struct workqueue_struct *respond_queue; 
* ftdi_module_lock exists to protect access to global variables

*

*/

static struct semaphore ftdi_module_lock;

static struct mutex ftdi_module_lock;

static int ftdi_instances = 0;

static struct list_head ftdi_static_list;

/*
@@ -199,10 +200,10 @@ static void ftdi_elan_delete(struct kref *kref) 
        dev_warn(&ftdi->udev->dev, "FREEING ftdi=%p\n", ftdi);

        usb_put_dev(ftdi->udev);

        ftdi->disconnected += 1;

        down(&ftdi_module_lock);

        mutex_lock(&ftdi_module_lock);

        list_del_init(&ftdi->ftdi_list);

        ftdi_instances -= 1;

        up(&ftdi_module_lock);

        mutex_unlock(&ftdi_module_lock);

        kfree(ftdi->bulk_in_buffer);

        ftdi->bulk_in_buffer = NULL;

}
@@ -2780,10 +2781,10 @@ static int ftdi_elan_probe(struct usb_interface *interface, 
                return -ENOMEM;

        }

        memset(ftdi, 0x00, sizeof(struct usb_ftdi));

        down(&ftdi_module_lock);

        mutex_lock(&ftdi_module_lock);

        list_add_tail(&ftdi->ftdi_list, &ftdi_static_list);

        ftdi->sequence_num = ++ftdi_instances;

        up(&ftdi_module_lock);

        mutex_unlock(&ftdi_module_lock);

        ftdi_elan_init_kref(ftdi);

        init_MUTEX(&ftdi->sw_lock);

        ftdi->udev = usb_get_dev(interface_to_usbdev(interface));
@@ -2909,7 +2910,7 @@ static int __init ftdi_elan_init(void) 
        int result;

        printk(KERN_INFO "driver %s built at %s on %s\n", ftdi_elan_driver.name,

	       __TIME__, __DATE__);

        init_MUTEX(&ftdi_module_lock);

        mutex_init(&ftdi_module_lock);

        INIT_LIST_HEAD(&ftdi_static_list);

        status_queue = create_singlethread_workqueue("ftdi-status-control");

	if (!status_queue)