Commit 69f545ea authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Linus Torvalds
Browse files

use mutex instead of semaphore in RocketPort driver 



The RocketPort driver uses a semaphore as mutex.  Use the mutex API instead of
the (binary) semaphore.

Signed-off-by: default avatarMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6bdb6b62

drivers/char/rocket.c

+11 −8
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ 
#include <linux/string.h>

#include <linux/fcntl.h>

#include <linux/ptrace.h>

#include <linux/mutex.h>

#include <linux/ioport.h>

#include <linux/delay.h>

#include <linux/wait.h>
@@ -89,7 +90,6 @@ 
#include <asm/atomic.h>

#include <linux/bitops.h>

#include <linux/spinlock.h>

#include <asm/semaphore.h>

#include <linux/init.h>



/****** RocketPort includes ******/
@@ -698,7 +698,7 @@ 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_mtx);

	rp_table[line] = info;

	if (pci_dev)

		tty_register_device(rocket_driver, line, &pci_dev->dev);
@@ -1657,8 +1657,11 @@ 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_mtx);



#ifdef ROCKET_DEBUG_WRITE

	printk(KERN_INFO "rp_put_char %c...", ch);
@@ -1680,12 +1683,12 @@ 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_mtx);

}



/*

 *  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.
@@ -1702,7 +1705,7 @@ static int rp_write(struct tty_struct *tty, 
	if (count <= 0 || rocket_paranoia_check(info, "rp_write"))

		return 0;



	down_interruptible(&info->write_sem);

	mutex_lock_interruptible(&info->write_mtx);



#ifdef ROCKET_DEBUG_WRITE

	printk(KERN_INFO "rp_write %d chars...", count);
@@ -1773,7 +1776,7 @@ end: 
		wake_up_interruptible(&tty->poll_wait);

#endif

	}

	up(&info->write_sem);

	mutex_unlock(&info->write_mtx);

	return retval;

}

drivers/char/rocket_int.h

+3 −1
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ 
#define ROCKET_TYPE_MODEMIII	3

#define ROCKET_TYPE_PC104       4



#include <linux/mutex.h>



#include <asm/io.h>

#include <asm/byteorder.h>
@@ -1171,7 +1173,7 @@ struct r_port { 
	struct wait_queue *close_wait;

#endif

	spinlock_t slock;

	struct semaphore write_sem;

	struct mutex write_mtx;

};



#define RPORT_MAGIC 0x525001

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