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Commit c831c338 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Linus Torvalds
Browse files

use mutex instead of semaphore in virtual console driver 



The virtual console 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>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 159dde93

drivers/char/vc_screen.c

+10 −8
Original line number Diff line number Diff line
@@ -28,11 +28,13 @@ 
#include <linux/interrupt.h>

#include <linux/mm.h>

#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/vt_kern.h>

#include <linux/selection.h>

#include <linux/kbd_kern.h>

#include <linux/console.h>

#include <linux/device.h>



#include <asm/uaccess.h>

#include <asm/byteorder.h>

#include <asm/unaligned.h>
@@ -69,11 +71,11 @@ static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) 
{

	int size;



	down(&con_buf_sem);

	mutex_lock(&con_buf_mtx);

	size = vcs_size(file->f_path.dentry->d_inode);

	switch (orig) {

		default:

			up(&con_buf_sem);

			mutex_unlock(&con_buf_mtx);

			return -EINVAL;

		case 2:

			offset += size;
@@ -84,11 +86,11 @@ static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) 
			break;

	}

	if (offset < 0 || offset > size) {

		up(&con_buf_sem);

		mutex_unlock(&con_buf_mtx);

		return -EINVAL;

	}

	file->f_pos = offset;

	up(&con_buf_sem);

	mutex_unlock(&con_buf_mtx);

	return file->f_pos;

}
@@ -105,7 +107,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 
	unsigned short *org = NULL;

	ssize_t ret;



	down(&con_buf_sem);

	mutex_lock(&con_buf_mtx);



	pos = *ppos;
@@ -262,7 +264,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 
		ret = read;

unlock_out:

	release_console_sem();

	up(&con_buf_sem);

	mutex_unlock(&con_buf_mtx);

	return ret;

}
@@ -279,7 +281,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
	u16 *org0 = NULL, *org = NULL;

	size_t ret;



	down(&con_buf_sem);

	mutex_lock(&con_buf_mtx);



	pos = *ppos;
@@ -449,7 +451,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
unlock_out:

	release_console_sem();



	up(&con_buf_sem);

	mutex_unlock(&con_buf_mtx);



	return ret;

}

drivers/char/vt.c

+3 −2
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ 
#include <linux/mm.h>

#include <linux/console.h>

#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/vt_kern.h>

#include <linux/selection.h>

#include <linux/tiocl.h>
@@ -1952,7 +1953,7 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) 
 * kernel memory allocation is available.

 */

char con_buf[CON_BUF_SIZE];

DECLARE_MUTEX(con_buf_sem);

DEFINE_MUTEX(con_buf_mtx);



/* is_double_width() is based on the wcwidth() implementation by

 * Markus Kuhn -- 2003-05-20 (Unicode 4.0)
@@ -2049,7 +2050,7 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 


	/* At this point 'buf' is guaranteed to be a kernel buffer

	 * and therefore no access to userspace (and therefore sleeping)

	 * will be needed.  The con_buf_sem serializes all tty based

	 * will be needed.  The con_buf_mtx serializes all tty based

	 * console rendering and vcs write/read operations.  We hold

	 * the console spinlock during the entire write.

	 */

include/linux/vt_kern.h

+2 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/vt.h>

#include <linux/kd.h>

#include <linux/tty.h>

#include <linux/mutex.h>

#include <linux/console_struct.h>

#include <linux/mm.h>
@@ -82,7 +83,7 @@ void reset_vc(struct vc_data *vc); 


#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)

extern char con_buf[CON_BUF_SIZE];

extern struct semaphore con_buf_sem;

extern struct mutex con_buf_mtx;

extern char vt_dont_switch;



struct vt_spawn_console {