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Subject[PATCH 1/3] staging: dgnc: use a real mutex instead of masquerading a semaphore as a mutex
Date
A mutex should be used here (and it's name even says that) so remove the hiding
of a semaphore behind a #define and use a real mutex that the kernel provides.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@gmail.com>
---
drivers/staging/dgnc/dgnc_tty.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_tty.c b/drivers/staging/dgnc/dgnc_tty.c
index ce4187f..0b9bed4 100644
--- a/drivers/staging/dgnc/dgnc_tty.c
+++ b/drivers/staging/dgnc/dgnc_tty.c
@@ -42,16 +42,12 @@
#include "dgnc_sysfs.h"
#include "dgnc_utils.h"

-#define init_MUTEX(sem) sema_init(sem, 1)
-#define DECLARE_MUTEX(name) \
- struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
-
/*
* internal variables
*/
static struct dgnc_board *dgnc_BoardsByMajor[256];
static unsigned char *dgnc_TmpWriteBuf;
-static DECLARE_MUTEX(dgnc_TmpWriteSem);
+static DEFINE_MUTEX(dgnc_TmpWriteSem);

/*
* Default transparent print information.
@@ -1797,7 +1793,7 @@ static int dgnc_tty_write(struct tty_struct *tty,
* the board.
*/
/* we're allowed to block if it's from_user */
- if (down_interruptible(&dgnc_TmpWriteSem))
+ if (mutex_lock_interruptible(&dgnc_TmpWriteSem))
return -EINTR;

/*
@@ -1807,7 +1803,7 @@ static int dgnc_tty_write(struct tty_struct *tty,
count -= copy_from_user(dgnc_TmpWriteBuf, (const unsigned char __user *) buf, count);

if (!count) {
- up(&dgnc_TmpWriteSem);
+ mutex_unlock(&dgnc_TmpWriteSem);
return -EFAULT;
}

@@ -1855,7 +1851,7 @@ static int dgnc_tty_write(struct tty_struct *tty,

if (from_user) {
spin_unlock_irqrestore(&ch->ch_lock, flags);
- up(&dgnc_TmpWriteSem);
+ mutex_unlock(&dgnc_TmpWriteSem);
} else {
spin_unlock_irqrestore(&ch->ch_lock, flags);
}
--
2.3.5


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