On Tue, Oct 19, 2021 at 07:48:15PM +0100, David Howells wrote:

Matthew Wilcox [off-list ref] wrote:

quoted

quoted

+		isize = i_size_read(inode);
+		if (unlikely(iocb->ki_pos >= isize))
+			goto put_pages;
+

Is there a good reason to assign to isize here?  I'd rather not,
because it complicates analysis, and a later change might look at
the isize read here, not realising it was a racy use.  So I'd
rather see:

If we don't set isize, the loop will never end.  Actually, maybe we can just
break out at that point rather than going to put_pages.

Umm, yes, of course.  Sorry.

It makes more sense to just break because we haven't got any pages,
so putting pages that we haven't got seems unnecessary.