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Commit ecb3b80f authored by Santosh Nayak's avatar Santosh Nayak Committed by Greg Kroah-Hartman
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Staging: vme: Replace semaphore by mutex. 



Replace binary semaphore by mutex for code cleanup.
Mutex also gives better performance than semaphore.

Add 'mutex_destroy()' in 'vme_user_remove()' routine.

Signed-off-by: default avatarSantosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f56d711b

drivers/staging/vme/devices/vme_user.c

+22 −21
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#include <linux/module.h>

#include <linux/pagemap.h>

#include <linux/pci.h>

#include <linux/semaphore.h>

#include <linux/mutex.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/syscalls.h>
@@ -95,7 +95,7 @@ struct image_desc { 
	void *kern_buf;	/* Buffer address in kernel space */

	dma_addr_t pci_buf;	/* Buffer address in PCI address space */

	unsigned long long size_buf;	/* Buffer size */

	struct semaphore sem;	/* Semaphore for locking image */

	struct mutex mutex;	/* Mutex for locking image */

	struct device *device;	/* Sysfs device */

	struct vme_resource *resource;	/* VME resource */

	int users;		/* Number of current users */
@@ -168,7 +168,7 @@ static int vme_user_open(struct inode *inode, struct file *file) 
	int err;

	unsigned int minor = MINOR(inode->i_rdev);



	down(&image[minor].sem);

	mutex_lock(&image[minor].mutex);

	/* Allow device to be opened if a resource is needed and allocated. */

	if (minor < CONTROL_MINOR && image[minor].resource == NULL) {

		printk(KERN_ERR "No resources allocated for device\n");
@@ -179,12 +179,12 @@ static int vme_user_open(struct inode *inode, struct file *file) 
	/* Increment user count */

	image[minor].users++;



	up(&image[minor].sem);

	mutex_unlock(&image[minor].mutex);



	return 0;



err_res:

	up(&image[minor].sem);

	mutex_unlock(&image[minor].mutex);



	return err;

}
@@ -193,12 +193,12 @@ static int vme_user_release(struct inode *inode, struct file *file) 
{

	unsigned int minor = MINOR(inode->i_rdev);



	down(&image[minor].sem);

	mutex_lock(&image[minor].mutex);



	/* Decrement user count */

	image[minor].users--;



	up(&image[minor].sem);

	mutex_unlock(&image[minor].mutex);



	return 0;

}
@@ -325,14 +325,14 @@ static ssize_t vme_user_read(struct file *file, char __user *buf, size_t count, 
	if (minor == CONTROL_MINOR)

		return 0;



	down(&image[minor].sem);

	mutex_lock(&image[minor].mutex);



	/* XXX Do we *really* want this helper - we can use vme_*_get ? */

	image_size = vme_get_size(image[minor].resource);



	/* Ensure we are starting at a valid location */

	if ((*ppos < 0) || (*ppos > (image_size - 1))) {

		up(&image[minor].sem);

		mutex_unlock(&image[minor].mutex);

		return 0;

	}
@@ -353,8 +353,7 @@ static ssize_t vme_user_read(struct file *file, char __user *buf, size_t count, 
		retval = -EINVAL;

	}



	up(&image[minor].sem);



	mutex_unlock(&image[minor].mutex);

	if (retval > 0)

		*ppos += retval;
@@ -372,13 +371,13 @@ static ssize_t vme_user_write(struct file *file, const char __user *buf, 
	if (minor == CONTROL_MINOR)

		return 0;



	down(&image[minor].sem);

	mutex_lock(&image[minor].mutex);



	image_size = vme_get_size(image[minor].resource);



	/* Ensure we are starting at a valid location */

	if ((*ppos < 0) || (*ppos > (image_size - 1))) {

		up(&image[minor].sem);

		mutex_unlock(&image[minor].mutex);

		return 0;

	}
@@ -399,7 +398,7 @@ static ssize_t vme_user_write(struct file *file, const char __user *buf, 
		retval = -EINVAL;

	}

	

	up(&image[minor].sem);

	mutex_unlock(&image[minor].mutex);



	if (retval > 0)

		*ppos += retval;
@@ -416,7 +415,7 @@ static loff_t vme_user_llseek(struct file *file, loff_t off, int whence) 
	if (minor == CONTROL_MINOR)

		return -EINVAL;



	down(&image[minor].sem);

	mutex_lock(&image[minor].mutex);

	image_size = vme_get_size(image[minor].resource);



	switch (whence) {
@@ -430,19 +429,19 @@ static loff_t vme_user_llseek(struct file *file, loff_t off, int whence) 
		absolute = image_size + off;

		break;

	default:

		up(&image[minor].sem);

		mutex_unlock(&image[minor].mutex);

		return -EINVAL;

		break;

	}



	if ((absolute < 0) || (absolute >= image_size)) {

		up(&image[minor].sem);

		mutex_unlock(&image[minor].mutex);

		return -EINVAL;

	}



	file->f_pos = absolute;



	up(&image[minor].sem);

	mutex_unlock(&image[minor].mutex);



	return absolute;

}
@@ -696,7 +695,7 @@ static int __devinit vme_user_probe(struct vme_dev *vdev) 
	for (i = 0; i < VME_DEVS; i++) {

		image[i].kern_buf = NULL;

		image[i].pci_buf = 0;

		sema_init(&image[i].sem, 1);

		mutex_init(&image[i].mutex);

		image[i].device = NULL;

		image[i].resource = NULL;

		image[i].users = 0;
@@ -858,8 +857,10 @@ static int __devexit vme_user_remove(struct vme_dev *dev) 
	int i;



	/* Remove sysfs Entries */

	for (i = 0; i < VME_DEVS; i++)

	for (i = 0; i < VME_DEVS; i++) {

		mutex_destroy(&image[i].mutex);

		device_destroy(vme_user_sysfs_class, MKDEV(VME_MAJOR, i));

	}

	class_destroy(vme_user_sysfs_class);



	for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {