On Sun, 2021-06-13 at 16:15 +0100, Matthew Wilcox wrote:
On Sun, Jun 13, 2021 at 08:02:12AM -0400, Jeff Layton wrote:
- /* clamp length to end of the current page */
- if (len > PAGE_SIZE)
len = PAGE_SIZE - offset;Actually, I think this should be:
len = min(len, PAGE_SIZE - offset);
Otherwise, len could still go beyond the end of the page.
I don't understand why you want to clamp length instead of just coping with len being > PAGE_SIZE.
- /* full page write */
- if (offset == 0 && len == PAGE_SIZE)
goto zero_out;That becomes >=.
- /* zero-length file */
- if (i_size == 0)
goto zero_out;- /* position beyond last page in the file */
- if (index > ((i_size - 1) / PAGE_SIZE))
goto zero_out;- /* write that covers the the page from start to EOF or beyond it */
- if (offset == 0 && (pos + len) >= i_size)
goto zero_out;That doesn't need any change.
- return false;
+zero_out:
- zero_user_segments(page, 0, offset, offset + len, PAGE_SIZE);
That also doesn't need any change.
Won't it though? offset+len will could be beyond the end of the page at that point. Hmm I guess zero_user_segments does this:
if (start2 >= end2) start2 = end2 = 0;
...so that makes the second segment copy a no-op.
Ok, fair enough -- I'll get rid of the clamping and just allow len to be longer than PAGE_SIZE in the checks.
Thanks,