Use mutex instead of binary semaphore for mutual exclusion.
Signed-off-by: Milind Arun Choudhary <[email protected]>
---
rocket.c | 22 ++++++++++++----------
rocket_int.h | 2 +-
2 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/char/rocket.c b/drivers/char/rocket.c
index 76357c8..07255c3 100644
--- a/drivers/char/rocket.c
+++ b/drivers/char/rocket.c
@@ -35,7 +35,7 @@
* is data to be transmitted. Protected by atomic bit operations.
* - rp_num_ports, int indicating number of open ports, protected by atomic operations.
*
- * rp_write() and rp_write_char() functions use a per port semaphore to protect against
+ * rp_write() and rp_write_char() functions use a per port mutex to protect against
* simultaneous access to the same port by more than one process.
*/
@@ -67,7 +67,7 @@
#ifdef MODVERSIONS
#include <config/modversions.h>
-#endif
+#endif
#include <linux/module.h>
#include <linux/errno.h>
@@ -93,7 +93,7 @@
#include <asm/atomic.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
#include <linux/init.h>
/****** RocketPort includes ******/
@@ -702,7 +702,7 @@ static void init_r_port(int board, int aiop, int chan, struct pci_dev *pci_dev)
}
}
spin_lock_init(&info->slock);
- sema_init(&info->write_sem, 1);
+ mutex_init(&info->write_lock);
rp_table[line] = info;
if (pci_dev)
tty_register_device(rocket_driver, line, &pci_dev->dev);
@@ -1661,8 +1661,8 @@ static void rp_put_char(struct tty_struct *tty, unsigned char ch)
if (rocket_paranoia_check(info, "rp_put_char"))
return;
- /* Grab the port write semaphore, locking out other processes that try to write to this port */
- down(&info->write_sem);
+ /* Grab the port write mutex, locking out other processes that try to write to this port */
+ mutex_lock(&info->write_lock);
#ifdef ROCKET_DEBUG_WRITE
printk(KERN_INFO "rp_put_char %c...", ch);
@@ -1684,12 +1684,12 @@ static void rp_put_char(struct tty_struct *tty, unsigned char ch)
info->xmit_fifo_room--;
}
spin_unlock_irqrestore(&info->slock, flags);
- up(&info->write_sem);
+ mutex_unlock(&info->write_lock);
}
/*
* Exception handler - write routine, called when user app writes to the device.
- * A per port write semaphore is used to protect from another process writing to
+ * A per port write mutex is used to protect from another process writing to
* this port at the same time. This other process could be running on the other CPU
* or get control of the CPU if the copy_from_user() blocks due to a page fault (swapped out).
* Spinlocks protect the info xmit members.
@@ -1706,7 +1706,9 @@ static int rp_write(struct tty_struct *tty,
if (count <= 0 || rocket_paranoia_check(info, "rp_write"))
return 0;
- down_interruptible(&info->write_sem);
+ if(mutex_lock_interruptible(&info->write_lock)){
+ return -ERESTARTSYS;
+ }
#ifdef ROCKET_DEBUG_WRITE
printk(KERN_INFO "rp_write %d chars...", count);
@@ -1777,7 +1779,7 @@ end:
wake_up_interruptible(&tty->poll_wait);
#endif
}
- up(&info->write_sem);
+ mutex_unlock(&info->write_lock);
return retval;
}
diff --git a/drivers/char/rocket_int.h b/drivers/char/rocket_int.h
index 3a8bcc8..e91a1cb 100644
--- a/drivers/char/rocket_int.h
+++ b/drivers/char/rocket_int.h
@@ -1171,7 +1171,7 @@ struct r_port {
struct wait_queue *close_wait;
#endif
spinlock_t slock;
- struct semaphore write_sem;
+ struct mutex write_lock;
};
#define RPORT_MAGIC 0x525001
--
Milind Arun Choudhary
-
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