[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: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 10dfdf0..83e2594 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -589,17 +589,19 @@
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;
+ return 0;
+
if (count >= total_size)
- 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 @@
}
kfree(buffer);
+
return (err) ? err : cnt;
}
@@ -648,7 +651,7 @@
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 @@
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) {
- count = total_size - p;
- err = -ENOSPC;
- }
- cnt = 0;
+ count = total_size;
+
+ if (count + p > total_size)
+ count = total_size - p;
+
buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,
GFP_KERNEL);
if (!buffer)
@@ -687,12 +690,15 @@
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 @@
dst = (u32 __iomem *) dst8;
}
+
*ppos += c;
buf += c;
cnt += c;
count -= c;
}
+
kfree(buffer);
return (err) ? err : cnt;