[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 10dfdf0352644d296247f3a18f17c3302f615189..83e259413115066ae5b15ac0d19fa92b49dd3462 100644 (file)
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -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;
+               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 @@ 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) {
-           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 @@ 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;