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Message-Id: <1333451571-17765-1-git-send-email-santoshprasadnayak@gmail.com>
Date: Tue, 3 Apr 2012 16:42:51 +0530
From: santosh nayak <santoshprasadnayak@...il.com>
To: gregkh@...uxfoundation.org
Cc: martyn.welch@...com, devel@...verdev.osuosl.org,
linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
Santosh Nayak <santoshprasadnayak@...il.com>
Subject: [PATCH] Staging: vme: Replace semaphore by mutex.
From: Santosh Nayak <santoshprasadnayak@...il.com>
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@...il.com>
---
drivers/staging/vme/devices/vme_user.c | 43 ++++++++++++++++---------------
1 files changed, 22 insertions(+), 21 deletions(-)
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 7dcd162..10269d5 100644
--- 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++) {
--
1.7.4.4
--
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