On 10/27/19 10:49 AM, Jens Axboe wrote:

On 10/27/19 10:44 AM, Pavel Begunkov wrote:

quoted

On 27/10/2019 19:32, Jens Axboe wrote:

quoted

On 10/27/19 9:35 AM, Pavel Begunkov wrote:

quoted

A small cleanup of very similar but diverged io_submit_sqes() and
io_ring_submit()

Pavel Begunkov (2):
     io_uring: handle mm_fault outside of submission
     io_uring: merge io_submit_sqes and io_ring_submit

    fs/io_uring.c | 116 ++++++++++++++------------------------------------
    1 file changed, 33 insertions(+), 83 deletions(-)

I like the cleanups here, but one thing that seems off is the
assumption that io_sq_thread() always needs to grab the mm. If
the sqes processed are just READ/WRITE_FIXED, then it never needs
to grab the mm.
Yeah, we removed it to fix bugs. Personally, I think it would be

clearer to do lazy grabbing conditionally, rather than have two
functions. And in this case it's easier to do after merging.

Do you prefer to return it back first?

Ah I see, no I don't care about that.

OK, looked at the post-patches state. It's still not correct. You are
grabbing the mm from io_sq_thread() unconditionally. We should not do
that, only if the sqes we need to submit need mm context.

-- 
Jens Axboe