Commit 3e680aae authored by Krzysztof Helt's avatar Krzysztof Helt Committed by Linus Torvalds
Browse files

fb: convert lock/unlock_kernel() into local fb mutex 



Change lock_kernel()/unlock_kernel() to local fb mutex.  Each frame buffer
instance has its own mutex.

The one line try_to_load() function is unrolled to request_module() in two
places for readability.

[righi.andrea@gmail.com: fb: fix NULL pointer BUG dereference in fb_open()]
Signed-off-by: default avatarKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: default avatarAndrea Righi <righi.andrea@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5367711

drivers/video/fbmem.c

+20 −19
Original line number Diff line number Diff line
@@ -1018,12 +1018,12 @@ fb_ioctl(struct file *file, unsigned int cmd, 
	void __user *argp = (void __user *)arg;

	long ret = 0;



	lock_kernel();

	info = registered_fb[fbidx];

	mutex_lock(&info->lock);

	fb = info->fbops;



	if (!fb) {

		unlock_kernel();

		mutex_unlock(&info->lock);

		return -ENODEV;

	}

	switch (cmd) {
@@ -1126,7 +1126,7 @@ fb_ioctl(struct file *file, unsigned int cmd, 
		else

			ret = fb->fb_ioctl(info, cmd, arg);

	}

	unlock_kernel();

	mutex_unlock(&info->lock);

	return ret;

}
@@ -1253,7 +1253,7 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	struct fb_ops *fb = info->fbops;

	long ret = -ENOIOCTLCMD;



	lock_kernel();

	mutex_lock(&info->lock);

	switch(cmd) {

	case FBIOGET_VSCREENINFO:

	case FBIOPUT_VSCREENINFO:
@@ -1279,7 +1279,7 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
			ret = fb->fb_compat_ioctl(info, cmd, arg);

		break;

	}

	unlock_kernel();

	mutex_unlock(&info->lock);

	return ret;

}

#endif
@@ -1301,13 +1301,13 @@ fb_mmap(struct file *file, struct vm_area_struct * vma) 
		return -ENODEV;

	if (fb->fb_mmap) {

		int res;

		lock_kernel();

		mutex_lock(&info->lock);

		res = fb->fb_mmap(info, vma);

		unlock_kernel();

		mutex_unlock(&info->lock);

		return res;

	}



	lock_kernel();

	mutex_lock(&info->lock);



	/* frame buffer memory */

	start = info->fix.smem_start;
@@ -1316,13 +1316,13 @@ fb_mmap(struct file *file, struct vm_area_struct * vma) 
		/* memory mapped io */

		off -= len;

		if (info->var.accel_flags) {

			unlock_kernel();

			mutex_unlock(&info->lock);

			return -EINVAL;

		}

		start = info->fix.mmio_start;

		len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.mmio_len);

	}

	unlock_kernel();

	mutex_unlock(&info->lock);

	start &= PAGE_MASK;

	if ((vma->vm_end - vma->vm_start + off) > len)

		return -EINVAL;
@@ -1346,13 +1346,13 @@ fb_open(struct inode *inode, struct file *file) 


	if (fbidx >= FB_MAX)

		return -ENODEV;

	lock_kernel();

	if (!(info = registered_fb[fbidx]))

	info = registered_fb[fbidx];

	if (!info)

		request_module("fb%d", fbidx);

	if (!(info = registered_fb[fbidx])) {

		res = -ENODEV;

		goto out;

	}

	info = registered_fb[fbidx];

	if (!info)

		return -ENODEV;

	mutex_lock(&info->lock);

	if (!try_module_get(info->fbops->owner)) {

		res = -ENODEV;

		goto out;
@@ -1368,7 +1368,7 @@ fb_open(struct inode *inode, struct file *file) 
		fb_deferred_io_open(info, inode, file);

#endif

out:

	unlock_kernel();

	mutex_unlock(&info->lock);

	return res;

}
@@ -1377,11 +1377,11 @@ fb_release(struct inode *inode, struct file *file) 
{

	struct fb_info * const info = file->private_data;



	lock_kernel();

	mutex_lock(&info->lock);

	if (info->fbops->fb_release)

		info->fbops->fb_release(info,1);

	module_put(info->fbops->owner);

	unlock_kernel();

	mutex_unlock(&info->lock);

	return 0;

}
@@ -1460,6 +1460,7 @@ register_framebuffer(struct fb_info *fb_info) 
		if (!registered_fb[i])

			break;

	fb_info->node = i;

	mutex_init(&fb_info->lock);



	fb_info->dev = device_create(fb_class, fb_info->device,

				     MKDEV(FB_MAJOR, i), NULL, "fb%d", i);

include/linux/fb.h

+1 −0
Original line number Diff line number Diff line
@@ -808,6 +808,7 @@ struct fb_tile_ops { 
struct fb_info {

	int node;

	int flags;

	struct mutex lock;		/* Lock for open/release/ioctl funcs */

	struct fb_var_screeninfo var;	/* Current var */

	struct fb_fix_screeninfo fix;	/* Current fix */

	struct fb_monspecs monspecs;	/* Current Monitor specs */

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