On 03/09/2017 09:32 PM, NeilBrown wrote:

I started looking further at the improvements we can make once
generic_make_request is fixed, and realised that I had missed an
important detail in this patch.
Several places test current->bio_list, and two actually edit the list.
With this change, that cannot see the whole lists, so it could cause a
regression.

So I've revised the patch to make sure that the entire list of queued
bios remains visible, and change the relevant code to look at both
the new list and the old list.

Following that there are some patches which make the rescuer thread
optional, and then starts removing it from some easy-to-fix places.

Neil, note that the v2 patch is already in Linus tree as of earlier
today. You need to rebase the series, and if we need fixups on
top of v2, then that should be done separately and with increased
urgency.

-- 
Jens Axboe