[PATCHv5 00/11] direct-io dma alignment

[Eric Biggers]

On Tue, May 31, 2022 at 12:11:26PM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch at kernel.org>
> 
> The most significant change from v4 is the alignment is now checked
> prior to building the bio. This gets the expected EINVAL error for
> misaligned userspace iovecs in all cases now (Eric Biggers).
> 
> I've removed the legacy fs change, so only iomap filesystems get to use
> this alignement capability (Christoph Hellwig).
> 
> The block fops check for alignment returns a bool now (Damien).
> 
> Adjusted some comments, docs, and other minor style issues.
> 
> Reviews added for unchanged or trivially changed patches, removed
> reviews for ones that changed more significantly.
> 
> As before, I tested using 'fio' with forced misaligned user buffers on
> raw block, xfs, and ext4 (example raw block profile below).
> 

I still don't think you've taken care of all the assumptions that bv_len is a
multiple of logical block size, or at least SECTOR_SIZE.  Try this:

	git grep -E 'bv_len (>>|/)'

Also:

	git grep '<.*bv_len;'

Also take a look at bio_for_each_segment(), specifically how iter->bi_sector is
updated.

- Eric