[PATCH] USB: convert a bunch of USB semaphores to mutexes

the patch below converts a bunch of semaphores-used-as-mutex in the USB
code to mutexes

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 41 insertions, 34 deletions

diff --git a/drivers/usb/media/w9968cf.c b/drivers/usb/media/w9968cf.c
index 78cd1a577d26..b57dec3782e0 100644
--- a/drivers/usb/media/w9968cf.c
+++ b/drivers/usb/media/w9968cf.c
@@ -47,6 +47,13 @@
 #include "w9968cf.h"
 #include "w9968cf_decoder.h"
 
+static struct w9968cf_vpp_t* w9968cf_vpp;
+static DECLARE_WAIT_QUEUE_HEAD(w9968cf_vppmod_wait);
+
+static LIST_HEAD(w9968cf_dev_list); /* head of V4L registered cameras list */
+static DEFINE_MUTEX(w9968cf_devlist_mutex); /* semaphore for list traversal */
+
+static DECLARE_RWSEM(w9968cf_disconnect); /* prevent races with open() */
 
 
 /****************************************************************************
@@ -2418,7 +2425,7 @@ w9968cf_configure_camera(struct w9968cf_device* cam,
                          enum w9968cf_model_id mod_id,
                          const unsigned short dev_nr)
 {
-        init_MUTEX(&cam->fileop_sem);
+        mutex_init(&cam->fileop_mutex);
         init_waitqueue_head(&cam->open);
         spin_lock_init(&cam->urb_lock);
         spin_lock_init(&cam->flist_lock);
@@ -2646,7 +2653,7 @@ static void w9968cf_adjust_configuration(struct w9968cf_device* cam)
   --------------------------------------------------------------------------*/
 static void w9968cf_release_resources(struct w9968cf_device* cam)
 {
-        down(&w9968cf_devlist_sem);
+        mutex_lock(&w9968cf_devlist_mutex);
 
         DBG(2, "V4L device deregistered: /dev/video%d", cam->v4ldev->minor)
 
@@ -2657,7 +2664,7 @@ static void w9968cf_release_resources(struct w9968cf_device* cam)
         kfree(cam->control_buffer);
         kfree(cam->data_buffer);
 
-        up(&w9968cf_devlist_sem);
+        mutex_unlock(&w9968cf_devlist_mutex);
 }
 
 
@@ -2677,14 +2684,14 @@ static int w9968cf_open(struct inode* inode, struct file* filp)
 
         cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));
 
-        down(&cam->dev_sem);
+        mutex_lock(&cam->dev_mutex);
 
         if (cam->sensor == CC_UNKNOWN) {
                 DBG(2, "No supported image sensor has been detected by the "
                        "'ovcamchip' module for the %s (/dev/video%d). Make "
                        "sure it is loaded *before* (re)connecting the camera.",
                     symbolic(camlist, cam->id), cam->v4ldev->minor)
-                up(&cam->dev_sem);
+                mutex_unlock(&cam->dev_mutex);
                 up_read(&w9968cf_disconnect);
                 return -ENODEV;
         }
@@ -2693,11 +2700,11 @@ static int w9968cf_open(struct inode* inode, struct file* filp)
                 DBG(2, "%s (/dev/video%d) has been already occupied by '%s'",
                     symbolic(camlist, cam->id),cam->v4ldev->minor,cam->command)
                 if ((filp->f_flags & O_NONBLOCK)||(filp->f_flags & O_NDELAY)) {
-                        up(&cam->dev_sem);
+                        mutex_unlock(&cam->dev_mutex);
                         up_read(&w9968cf_disconnect);
                         return -EWOULDBLOCK;
                 }
-                up(&cam->dev_sem);
+                mutex_unlock(&cam->dev_mutex);
                 err = wait_event_interruptible_exclusive(cam->open,
                                                          cam->disconnected ||
                                                          !cam->users);
@@ -2709,7 +2716,7 @@ static int w9968cf_open(struct inode* inode, struct file* filp)
                         up_read(&w9968cf_disconnect);
                         return -ENODEV;
                 }
-                down(&cam->dev_sem);
+                mutex_lock(&cam->dev_mutex);
         }
 
         DBG(5, "Opening '%s', /dev/video%d ...",
@@ -2738,7 +2745,7 @@ static int w9968cf_open(struct inode* inode, struct file* filp)
 
         DBG(5, "Video device is open")
 
-        up(&cam->dev_sem);
+        mutex_unlock(&cam->dev_mutex);
         up_read(&w9968cf_disconnect);
 
         return 0;
@@ -2746,7 +2753,7 @@ static int w9968cf_open(struct inode* inode, struct file* filp)
 deallocate_memory:
         w9968cf_deallocate_memory(cam);
         DBG(2, "Failed to open the video device")
-        up(&cam->dev_sem);
+        mutex_unlock(&cam->dev_mutex);
         up_read(&w9968cf_disconnect);
         return err;
 }
@@ -2758,13 +2765,13 @@ static int w9968cf_release(struct inode* inode, struct file* filp)
 
         cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));
 
-        down(&cam->dev_sem); /* prevent disconnect() to be called */
+        mutex_lock(&cam->dev_mutex); /* prevent disconnect() to be called */
 
         w9968cf_stop_transfer(cam);
 
         if (cam->disconnected) {
                 w9968cf_release_resources(cam);
-                up(&cam->dev_sem);
+                mutex_unlock(&cam->dev_mutex);
                 kfree(cam);
                 return 0;
         }
@@ -2774,7 +2781,7 @@ static int w9968cf_release(struct inode* inode, struct file* filp)
         wake_up_interruptible_nr(&cam->open, 1);
 
         DBG(5, "Video device closed")
-        up(&cam->dev_sem);
+        mutex_unlock(&cam->dev_mutex);
         return 0;
 }
 
@@ -2791,18 +2798,18 @@ w9968cf_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
         if (filp->f_flags & O_NONBLOCK)
                 return -EWOULDBLOCK;
 
-        if (down_interruptible(&cam->fileop_sem))
+        if (mutex_lock_interruptible(&cam->fileop_mutex))
                 return -ERESTARTSYS;
 
         if (cam->disconnected) {
                 DBG(2, "Device not present")
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -ENODEV;
         }
 
         if (cam->misconfigured) {
                 DBG(2, "The camera is misconfigured. Close and open it again.")
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -EIO;
         }
 
@@ -2817,11 +2824,11 @@ w9968cf_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
                                        cam->frame[1].status == F_READY ||
                                        cam->disconnected);
         if (err) {
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return err;
         }
         if (cam->disconnected) {
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -ENODEV;
         }
 
@@ -2835,7 +2842,7 @@ w9968cf_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
 
         if (copy_to_user(buf, fr->buffer, count)) {
                 fr->status = F_UNUSED;
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -EFAULT;
         }
         *f_pos += count;
@@ -2844,7 +2851,7 @@ w9968cf_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
 
         DBG(5, "%zu bytes read", count)
 
-        up(&cam->fileop_sem);
+        mutex_unlock(&cam->fileop_mutex);
         return count;
 }
 
@@ -2898,24 +2905,24 @@ w9968cf_ioctl(struct inode* inode, struct file* filp,
 
         cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));
 
-        if (down_interruptible(&cam->fileop_sem))
+        if (mutex_lock_interruptible(&cam->fileop_mutex))
                 return -ERESTARTSYS;
 
         if (cam->disconnected) {
                 DBG(2, "Device not present")
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -ENODEV;
         }
 
         if (cam->misconfigured) {
                 DBG(2, "The camera is misconfigured. Close and open it again.")
-                up(&cam->fileop_sem);
+                mutex_unlock(&cam->fileop_mutex);
                 return -EIO;
         }
 
         err = w9968cf_v4l_ioctl(inode, filp, cmd, (void __user *)arg);
 
-        up(&cam->fileop_sem);
+        mutex_unlock(&cam->fileop_mutex);
         return err;
 }
 
@@ -3502,8 +3509,8 @@ w9968cf_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
         if (!cam)
                 return -ENOMEM;
 
-        init_MUTEX(&cam->dev_sem);
-        down(&cam->dev_sem);
+        mutex_init(&cam->dev_mutex);
+        mutex_lock(&cam->dev_mutex);
 
         cam->usbdev = udev;
         /* NOTE: a local copy is used to avoid possible race conditions */
@@ -3515,10 +3522,10 @@ w9968cf_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
                 simcams = W9968CF_SIMCAMS;
 
         /* How many cameras are connected ? */
-        down(&w9968cf_devlist_sem);
+        mutex_lock(&w9968cf_devlist_mutex);
         list_for_each(ptr, &w9968cf_dev_list)
                 sc++;
-        up(&w9968cf_devlist_sem);
+        mutex_unlock(&w9968cf_devlist_mutex);
 
         if (sc >= simcams) {
                 DBG(2, "Device rejected: too many connected cameras "
@@ -3578,9 +3585,9 @@ w9968cf_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
         w9968cf_configure_camera(cam, udev, mod_id, dev_nr);
 
         /* Add a new entry into the list of V4L registered devices */
-        down(&w9968cf_devlist_sem);
+        mutex_lock(&w9968cf_devlist_mutex);
         list_add(&cam->v4llist, &w9968cf_dev_list);
-        up(&w9968cf_devlist_sem);
+        mutex_unlock(&w9968cf_devlist_mutex);
         dev_nr = (dev_nr < W9968CF_MAX_DEVICES-1) ? dev_nr+1 : 0;
 
         w9968cf_turn_on_led(cam);
@@ -3588,7 +3595,7 @@ w9968cf_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
         w9968cf_i2c_init(cam);
 
         usb_set_intfdata(intf, cam);
-        up(&cam->dev_sem);
+        mutex_unlock(&cam->dev_mutex);
         return 0;
 
 fail: /* Free unused memory */
@@ -3596,7 +3603,7 @@ fail: /* Free unused memory */
         kfree(cam->data_buffer);
         if (cam->v4ldev)
                 video_device_release(cam->v4ldev);
-        up(&cam->dev_sem);
+        mutex_unlock(&cam->dev_mutex);
         kfree(cam);
         return err;
 }
@@ -3611,7 +3618,7 @@ static void w9968cf_usb_disconnect(struct usb_interface* intf)
 
         if (cam) {
                 /* Prevent concurrent accesses to data */
-                down(&cam->dev_sem); 
+                mutex_lock(&cam->dev_mutex);
 
                 cam->disconnected = 1;
 
@@ -3630,7 +3637,7 @@ static void w9968cf_usb_disconnect(struct usb_interface* intf)
                 } else
                         w9968cf_release_resources(cam);
 
-                up(&cam->dev_sem);
+                mutex_unlock(&cam->dev_mutex);
 
                 if (!cam->users)
                         kfree(cam);