2014-04-17 15:52:32

by Kumar Gaurav

Subject: [PATCH 35/35] Staging:dgap:dgap_tty.c: Upgraded driver to use Mutex instead of semaphore

dgap driver uses semaphore for obtaining lock. I upgraded it to use MUTEX.

Signed-off-by: Kumar Gaurav <[email protected]>
---
drivers/staging/dgap/dgap_tty.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/dgap/dgap_tty.c b/drivers/staging/dgap/dgap_tty.c
index 2a7a372..0ca72a2 100755
--- a/drivers/staging/dgap/dgap_tty.c
+++ b/drivers/staging/dgap/dgap_tty.c
@@ -52,7 +52,7 @@
#include <asm/uaccess.h> /* For copy_from_user/copy_to_user */
#include <asm/io.h> /* For read[bwl]/write[bwl] */
#include <linux/pci.h>
-
+#include<linux/mutex.h>
#include "dgap_driver.h"
#include "dgap_tty.h"
#include "dgap_types.h"
@@ -61,18 +61,12 @@
#include "dgap_conf.h"
#include "dgap_sysfs.h"

-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)
-#define init_MUTEX(sem) sema_init(sem, 1)
-#define DECLARE_MUTEX(name) \
- struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
-#endif
-
/*
* internal variables
*/
static struct board_t *dgap_BoardsByMajor[256];
static uchar *dgap_TmpWriteBuf = NULL;
-static DECLARE_MUTEX(dgap_TmpWriteSem);
+static DEFINE_MUTEX(dgap_TmpWriteSem);

/*
* Default transparent print information.
@@ -2004,12 +1998,11 @@ static int dgap_tty_write(struct tty_struct *tty, const unsigned char *buf, int
* the board.
*/
/* we're allowed to block if it's from_user */
- if (down_interruptible(&dgap_TmpWriteSem)) {
+ if (mutex_lock_interruptible(&dgap_TmpWriteSem))
return (-EINTR);
- }

if (copy_from_user(dgap_TmpWriteBuf, (const uchar __user *) buf, count)) {
- up(&dgap_TmpWriteSem);
+ mutex_unlock(&dgap_TmpWriteSem);
printk("Write: Copy from user failed!\n");
return -EFAULT;
}
@@ -2093,7 +2086,7 @@ static int dgap_tty_write(struct tty_struct *tty, const unsigned char *buf, int

if (from_user) {
DGAP_UNLOCK(ch->ch_lock, lock_flags);
- up(&dgap_TmpWriteSem);
+ mutex_unlock(&dgap_TmpWriteSem);
}
else {
DGAP_UNLOCK(ch->ch_lock, lock_flags);
--
1.7.9.5

2014-04-17 15:54:59

by Kumar Gaurav

Subject: Re: [PATCH 35/35] Staging:dgap:dgap_tty.c: Upgraded driver to use Mutex instead of semaphore

Hi All,

Please ignore this patch. I'm sending with correct Subject Line
On Thursday 17 April 2014 09:21 PM, Kumar Gaurav wrote:
> dgap driver uses semaphore for obtaining lock. I upgraded it to use MUTEX.
>
> Signed-off-by: Kumar Gaurav <[email protected]>
> ---
> drivers/staging/dgap/dgap_tty.c | 17 +++++------------
> 1 file changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/dgap/dgap_tty.c b/drivers/staging/dgap/dgap_tty.c
> index 2a7a372..0ca72a2 100755
> --- a/drivers/staging/dgap/dgap_tty.c
> +++ b/drivers/staging/dgap/dgap_tty.c
> @@ -52,7 +52,7 @@
> #include <asm/uaccess.h> /* For copy_from_user/copy_to_user */
> #include <asm/io.h> /* For read[bwl]/write[bwl] */
> #include <linux/pci.h>
> -
> +#include<linux/mutex.h>
> #include "dgap_driver.h"
> #include "dgap_tty.h"
> #include "dgap_types.h"
> @@ -61,18 +61,12 @@
> #include "dgap_conf.h"
> #include "dgap_sysfs.h"
>
> -#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,37)
> -#define init_MUTEX(sem) sema_init(sem, 1)
> -#define DECLARE_MUTEX(name) \
> - struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
> -#endif
> -
> /*
> * internal variables
> */
> static struct board_t *dgap_BoardsByMajor[256];
> static uchar *dgap_TmpWriteBuf = NULL;
> -static DECLARE_MUTEX(dgap_TmpWriteSem);
> +static DEFINE_MUTEX(dgap_TmpWriteSem);
>
> /*
> * Default transparent print information.
> @@ -2004,12 +1998,11 @@ static int dgap_tty_write(struct tty_struct *tty, const unsigned char *buf, int
> * the board.
> */
> /* we're allowed to block if it's from_user */
> - if (down_interruptible(&dgap_TmpWriteSem)) {
> + if (mutex_lock_interruptible(&dgap_TmpWriteSem))
> return (-EINTR);
> - }
>
> if (copy_from_user(dgap_TmpWriteBuf, (const uchar __user *) buf, count)) {
> - up(&dgap_TmpWriteSem);
> + mutex_unlock(&dgap_TmpWriteSem);
> printk("Write: Copy from user failed!\n");
> return -EFAULT;
> }
> @@ -2093,7 +2086,7 @@ static int dgap_tty_write(struct tty_struct *tty, const unsigned char *buf, int
>
> if (from_user) {
> DGAP_UNLOCK(ch->ch_lock, lock_flags);
> - up(&dgap_TmpWriteSem);
> + mutex_unlock(&dgap_TmpWriteSem);
> }
> else {
> DGAP_UNLOCK(ch->ch_lock, lock_flags);