linux-kernel - [PATCH 5/5] use mutex instead of semaphore in the FTDI ELAN driver

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Message-ID: <20070713192946.GI18159@traven>
Date:	Fri, 13 Jul 2007 21:29:46 +0200
From:	Matthias Kaehlcke <matthias.kaehlcke@...il.com>
To:	gregkh@...e.de, linux-usb-users@...ts.sourceforge.net,
	linux-usb-devel@...ts.sourceforge.net
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: [PATCH 5/5] 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: Matthias Kaehlcke <matthias.kaehlcke@...il.com>

--

diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c
index e0f122e..7cc6883 100644
--- a/drivers/usb/misc/ftdi-elan.c
+++ b/drivers/usb/misc/ftdi-elan.c
@@ -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)

-- 
Matthias Kaehlcke
Linux Application Developer
Barcelona

             If liberty means anything at all, it means the
           right to tell people what they do not want to hear
                            (George Orwell)
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