use mutex instead of semaphore in virtual console driver (c831c338) · Commits · 戴 / test

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 {

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