Commit 0a484a3a authored by Antonino A. Daplas's avatar Antonino A. Daplas Committed by Linus Torvalds
Browse files

[PATCH] fbdev: Fix return code of fb_read and fb_write 



Make fb_read() and fb_write() return 0 (EOF) instead of -ENOSPC if reading at
or past the end of the framebuffer.  This fixes user space apps hanging if
info->fix.smem_len == 0.

Whitespace changes.

Signed-off-by: default avatarAntonino Daplas <adaplas@pol.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 244ab72d

drivers/video/fbmem.c

+20 −12
Original line number Diff line number Diff line
@@ -589,17 +589,19 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 
		return info->fbops->fb_read(file, buf, count, ppos);

	

	total_size = info->screen_size;



	if (total_size == 0)

		total_size = info->fix.smem_len;



	if (p >= total_size)

		return 0;



	if (count >= total_size)

		count = total_size;



	if (count + p > total_size)

		count = total_size - p;



	cnt = 0;

	buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,

			 GFP_KERNEL);

	if (!buffer)
@@ -636,6 +638,7 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 
	}



	kfree(buffer);



	return (err) ? err : cnt;

}
@@ -648,7 +651,7 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
	struct fb_info *info = registered_fb[fbidx];

	u32 *buffer, *src;

	u32 __iomem *dst;

	int c, i, cnt = 0, err;

	int c, i, cnt = 0, err = 0;

	unsigned long total_size;



	if (!info || !info->screen_base)
@@ -661,19 +664,19 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
		return info->fbops->fb_write(file, buf, count, ppos);

	

	total_size = info->screen_size;



	if (total_size == 0)

		total_size = info->fix.smem_len;



	if (p > total_size)

	    return -ENOSPC;

		return 0;



	if (count >= total_size)

		count = total_size;

	err = 0;

	if (count + p > total_size) {



	if (count + p > total_size)

		count = total_size - p;

	    err = -ENOSPC;

	}

	cnt = 0;



	buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,

			 GFP_KERNEL);

	if (!buffer)
@@ -687,12 +690,15 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
	while (count) {

		c = (count > PAGE_SIZE) ? PAGE_SIZE : count;

		src = buffer;



		if (copy_from_user(src, buf, c)) {

			err = -EFAULT;

			break;

		}



		for (i = c >> 2; i--; )

			fb_writel(*src++, dst++);



		if (c & 3) {

			u8 *src8 = (u8 *) src;

			u8 __iomem *dst8 = (u8 __iomem *) dst;
@@ -702,11 +708,13 @@ fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 


			dst = (u32 __iomem *) dst8;

		}



		*ppos += c;

		buf += c;

		cnt += c;

		count -= c;

	}



	kfree(buffer);



	return (err) ? err : cnt;

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