USB: rio500: simplify locking

Admitting that there can be only one device allows us to drop any
pretense about locking one device or a table of devices.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/rio500.c b/drivers/usb/misc/rio500.c
index a32d61a..27e9c78 100644 (file)
--- a/drivers/usb/misc/rio500.c
+++ b/drivers/usb/misc/rio500.c
@@ -51,7 +51,6 @@ struct rio_usb_data {
         char *obuf, *ibuf;              /* transfer buffers */
         char bulk_in_ep, bulk_out_ep;   /* Endpoint assignments */
         wait_queue_head_t wait_q;       /* for timeouts */
-       struct mutex lock;          /* general race avoidance */
 };
 
 static DEFINE_MUTEX(rio500_mutex);
@@ -63,10 +62,8 @@ static int open_rio(struct inode *inode, struct file *file)
 
        /* against disconnect() */
        mutex_lock(&rio500_mutex);
-       mutex_lock(&(rio->lock));
 
        if (rio->isopen || !rio->present) {
-               mutex_unlock(&(rio->lock));
                mutex_unlock(&rio500_mutex);
                return -EBUSY;
        }
@@ -74,7 +71,6 @@ static int open_rio(struct inode *inode, struct file *file)
 
        init_waitqueue_head(&rio->wait_q);
 
-       mutex_unlock(&(rio->lock));
 
        dev_info(&rio->rio_dev->dev, "Rio opened.\n");
        mutex_unlock(&rio500_mutex);
@@ -88,7 +84,6 @@ static int close_rio(struct inode *inode, struct file *file)
 
        /* against disconnect() */
        mutex_lock(&rio500_mutex);
-       mutex_lock(&(rio->lock));
 
        rio->isopen = 0;
        if (!rio->present) {
@@ -100,7 +95,6 @@ static int close_rio(struct inode *inode, struct file *file)
        } else {
                dev_info(&rio->rio_dev->dev, "Rio closed.\n");
        }
-       mutex_unlock(&(rio->lock));
        mutex_unlock(&rio500_mutex);
        return 0;
 }
@@ -115,7 +109,7 @@ static long ioctl_rio(struct file *file, unsigned int cmd, unsigned long arg)
        int retries;
        int retval=0;
 
-       mutex_lock(&(rio->lock));
+       mutex_lock(&rio500_mutex);
         /* Sanity check to make sure rio is connected, powered, etc */
         if (rio->present == 0 || rio->rio_dev == NULL) {
                retval = -ENODEV;
@@ -259,7 +253,7 @@ static long ioctl_rio(struct file *file, unsigned int cmd, unsigned long arg)
 
 
 err_out:
-       mutex_unlock(&(rio->lock));
+       mutex_unlock(&rio500_mutex);
        return retval;
 }
 
@@ -279,12 +273,12 @@ write_rio(struct file *file, const char __user *buffer,
        int errn = 0;
        int intr;
 
-       intr = mutex_lock_interruptible(&(rio->lock));
+       intr = mutex_lock_interruptible(&rio500_mutex);
        if (intr)
                return -EINTR;
         /* Sanity check to make sure rio is connected, powered, etc */
         if (rio->present == 0 || rio->rio_dev == NULL) {
-               mutex_unlock(&(rio->lock));
+               mutex_unlock(&rio500_mutex);
                return -ENODEV;
        }
 
@@ -307,7 +301,7 @@ write_rio(struct file *file, const char __user *buffer,
                                goto error;
                        }
                        if (signal_pending(current)) {
-                               mutex_unlock(&(rio->lock));
+                               mutex_unlock(&rio500_mutex);
                                return bytes_written ? bytes_written : -EINTR;
                        }
 
@@ -345,12 +339,12 @@ write_rio(struct file *file, const char __user *buffer,
                buffer += copy_size;
        } while (count > 0);
 
-       mutex_unlock(&(rio->lock));
+       mutex_unlock(&rio500_mutex);
 
        return bytes_written ? bytes_written : -EIO;
 
 error:
-       mutex_unlock(&(rio->lock));
+       mutex_unlock(&rio500_mutex);
        return errn;
 }
 
@@ -367,12 +361,12 @@ read_rio(struct file *file, char __user *buffer, size_t count, loff_t * ppos)
        char *ibuf;
        int intr;
 
-       intr = mutex_lock_interruptible(&(rio->lock));
+       intr = mutex_lock_interruptible(&rio500_mutex);
        if (intr)
                return -EINTR;
        /* Sanity check to make sure rio is connected, powered, etc */
         if (rio->present == 0 || rio->rio_dev == NULL) {
-               mutex_unlock(&(rio->lock));
+               mutex_unlock(&rio500_mutex);
                return -ENODEV;
        }
 
@@ -383,11 +377,11 @@ read_rio(struct file *file, char __user *buffer, size_t count, loff_t * ppos)
 
        while (count > 0) {
                if (signal_pending(current)) {
-                       mutex_unlock(&(rio->lock));
+                       mutex_unlock(&rio500_mutex);
                        return read_count ? read_count : -EINTR;
                }
                if (!rio->rio_dev) {
-                       mutex_unlock(&(rio->lock));
+                       mutex_unlock(&rio500_mutex);
                        return -ENODEV;
                }
                this_read = (count >= IBUF_SIZE) ? IBUF_SIZE : count;
@@ -405,7 +399,7 @@ read_rio(struct file *file, char __user *buffer, size_t count, loff_t * ppos)
                        count = this_read = partial;
                } else if (result == -ETIMEDOUT || result == 15) {      /* FIXME: 15 ??? */
                        if (!maxretry--) {
-                               mutex_unlock(&(rio->lock));
+                               mutex_unlock(&rio500_mutex);
                                dev_err(&rio->rio_dev->dev,
                                        "read_rio: maxretry timeout\n");
                                return -ETIME;
@@ -415,19 +409,19 @@ read_rio(struct file *file, char __user *buffer, size_t count, loff_t * ppos)
                        finish_wait(&rio->wait_q, &wait);
                        continue;
                } else if (result != -EREMOTEIO) {
-                       mutex_unlock(&(rio->lock));
+                       mutex_unlock(&rio500_mutex);
                        dev_err(&rio->rio_dev->dev,
                                "Read Whoops - result:%d partial:%u this_read:%u\n",
                                result, partial, this_read);
                        return -EIO;
                } else {
-                       mutex_unlock(&(rio->lock));
+                       mutex_unlock(&rio500_mutex);
                        return (0);
                }
 
                if (this_read) {
                        if (copy_to_user(buffer, ibuf, this_read)) {
-                               mutex_unlock(&(rio->lock));
+                               mutex_unlock(&rio500_mutex);
                                return -EFAULT;
                        }
                        count -= this_read;
@@ -435,7 +429,7 @@ read_rio(struct file *file, char __user *buffer, size_t count, loff_t * ppos)
                        buffer += this_read;
                }
        }
-       mutex_unlock(&(rio->lock));
+       mutex_unlock(&rio500_mutex);
        return read_count;
 }
 
@@ -500,8 +494,6 @@ static int probe_rio(struct usb_interface *intf,
        }
        dev_dbg(&intf->dev, "ibuf address:%p\n", rio->ibuf);
 
-       mutex_init(&(rio->lock));
-
        usb_set_intfdata (intf, rio);
        rio->present = 1;
 bail_out:
@@ -519,12 +511,10 @@ static void disconnect_rio(struct usb_interface *intf)
        if (rio) {
                usb_deregister_dev(intf, &usb_rio_class);
 
-               mutex_lock(&(rio->lock));
                if (rio->isopen) {
                        rio->isopen = 0;
                        /* better let it finish - the release will do whats needed */
                        rio->rio_dev = NULL;
-                       mutex_unlock(&(rio->lock));
                        mutex_unlock(&rio500_mutex);
                        return;
                }
@@ -534,7 +524,6 @@ static void disconnect_rio(struct usb_interface *intf)
                dev_info(&intf->dev, "USB Rio disconnected.\n");
 
                rio->present = 0;
-               mutex_unlock(&(rio->lock));
        }
        mutex_unlock(&rio500_mutex);
 }