[PATCH 2/5] use mutex instead of semaphore in Philips webcam driver

Matthias Kaehlcke
2007-07-01T16:29:40Z

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

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>

--

diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
index 085332a..9c0e8d1 100644
--- a/drivers/media/video/pwc/pwc-if.c
+++ b/drivers/media/video/pwc/pwc-if.c
@@ -1099,7 +1099,7 @@ static int pwc_video_open(struct inode *inode, struct file *file)
return -EBUSY;
}

- down(&pdev->modlock);
+ mutex_lock(&pdev->modlock);
if (!pdev->usb_init) {
PWC_DEBUG_OPEN("Doing first time initialization.\n");
pdev->usb_init = 1;
@@ -1131,7 +1131,7 @@ static int pwc_video_open(struct inode *inode, struct file *file)
if (i < 0) {
PWC_DEBUG_OPEN("Failed to allocate buffers memory.\n");
pwc_free_buffers(pdev);
- up(&pdev->modlock);
+ mutex_unlock(&pdev->modlock);
return i;
}

@@ -1172,7 +1172,7 @@ static int pwc_video_open(struct inode *inode, struct file *file)
if (i) {
PWC_DEBUG_OPEN("Second attempt at set_video_mode failed.\n");
pwc_free_buffers(pdev);
- up(&pdev->modlock);
+ mutex_unlock(&pdev->modlock);
return i;
}

@@ -1181,7 +1181,7 @@ static int pwc_video_open(struct inode *inode, struct file *file)
PWC_DEBUG_OPEN("Failed to init ISOC stuff = %d.\n", i);
pwc_isoc_cleanup(pdev);
pwc_free_buffers(pdev);
- up(&pdev->modlock);
+ mutex_unlock(&pdev->modlock);
return i;
}

@@ -1191,7 +1191,7 @@ static int pwc_video_open(struct inode *inode, struct file *file)

pdev->vopen++;
file->private_data = vdev;
- up(&pdev->modlock);
+ mutex_unlock(&pdev->modlock);
PWC_DEBUG_OPEN("<< video_open() returns 0.\n");
return 0;
}
@@ -1685,7 +1685,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
pdev->angle_range.tilt_max = 2500;
}

- init_MUTEX(&pdev->modlock);
+ mutex_init(&pdev->modlock);
spin_lock_init(&pdev->ptrlock);

pdev->udev = udev;
diff --git a/drivers/media/video/pwc/pwc.h b/drivers/media/video/pwc/pwc.h
index acbb931..910a04f 100644
--- a/drivers/media/video/pwc/pwc.h
+++ b/drivers/media/video/pwc/pwc.h
@@ -31,7 +31,7 @@
#include <linux/wait.h>
#include <linux/smp_lock.h>
#include <linux/version.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
#include <asm/errno.h>
#include <linux/videodev.h>
#include <media/v4l2-common.h>
@@ -244,7 +244,7 @@ struct pwc_device
int image_read_pos; /* In case we read data in pieces, keep track of were we are in the imagebuffer */
int image_used[MAX_IMAGES]; /* For MCAPTURE and SYNC */

- struct semaphore modlock; /* to prevent races in video_open(), etc */
+ struct mutex modlock; /* to prevent races in video_open(), etc */
spinlock_t ptrlock; /* for manipulating the buffer pointers */

/*** motorized pan/tilt feature */

--
Matthias Kaehlcke
Linux Application Developer
Barcelona

"The only important thing Windows does better
than Debian is implementing the win32 platform"