On Wed, Jul 26, 2017 at 01:12:28PM -0700, Christoph Hellwig wrote:

On Tue, Jul 25, 2017 at 06:02:29PM -0700, Dan Williams wrote:

quoted

As is done in zram_rw_page, pmem_rw_page, and btt_rw_page, don't
call page_endio in the error case since do_mpage_readpage and
__mpage_writepage will resubmit on error. Calling page_endio in the
error case leads to double completion.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Matthew Wilcox <redacted>
Cc: Ross Zwisler <redacted>
Signed-off-by: Dan Williams <redacted>
---
Noticed this while looking at unrelated brd code...

And the real question would be:  where would we see any real life impact
of just removing brd_rw_page?

I've got patches ready that remove rw_page from brd, btt and pmem.  I'll send
out once I'm done regression testing.