[PATCH] fbdev: Fix return error of fb_write

Antonino A. Daplas
2006-04-15T05:38:56Z

Fix return code of fb_write():

If at least 1 byte was transferred to the device, return number of bytes,
otherwise:

- return -EFBIG - if file offset is past the maximum allowable offset or
size is greater than framebuffer length
- return -ENOSPC - if size is greater than framebuffer length - offset

Signed-off-by: Antonino Daplas <adaplas@pol.net>
---

Andrew Morton wrote:
> "Antonino A. Daplas" <adaplas@gmail.com> wrote:
>> Richard Purdie wrote:
>>
>> - return -EFBIG if file offset is past the maximum allowable offset
>
> OK.
>
>> - return -EFBIG and write to end of framebuffer if size is bigger than the
>> framebuffer length
>
> We should return the number of bytes written in this case.
>
>> - return -ENOSPC and write to end of framebuffer if size is bigger than the
>> framebuffer length - file offset
>
> Also here.
>
>
> If we can transfer _any_ bytes, we should do so, then return the number of
> bytes transferred. If no bytes were transferrable then we should return
> -Ewhatever.
>
>

Okay, here's try #2:

drivers/video/fbmem.c | 14 ++++++++++----
1 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 944855b..a4b6776 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -669,13 +669,19 @@ fb_write(struct file *file, const char _
total_size = info->fix.smem_len;

if (p > total_size)
- return 0;
+ return -EFBIG;

- if (count >= total_size)
+ if (count > total_size) {
+ err = -EFBIG;
count = total_size;
+ }
+
+ if (count + p > total_size) {
+ if (!err)
+ err = -ENOSPC;

- if (count + p > total_size)
count = total_size - p;
+ }

buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,
GFP_KERNEL);
@@ -717,7 +723,7 @@ fb_write(struct file *file, const char _

kfree(buffer);

- return (err) ? err : cnt;
+ return (cnt) ? cnt : err;
}

#ifdef CONFIG_KMOD