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: Santosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 7dcd1622b5f5dd91f3e4d5e47b1e42f904ce7813..10269d59942f1d778c18d7368b7a4e634d197ab0 100644 (file)
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -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;
        }
 
@@ -398,8 +397,8 @@ static ssize_t vme_user_write(struct file *file, const char __user *buf,
        default:
                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++) {