On 6/18/18 10:16 AM, Al Viro wrote:

On Mon, Jun 18, 2018 at 09:37:01AM -0600, Jens Axboe wrote:

quoted

quoted

The folks responsible are no longer active in kernel development ***
but as far as I know the async write(command), read(response) were
added to bsg over 10 years ago as proof-of-concept and never properly
worked in this async mode. The biggest design problem with it that I'm

It was born with that mode, but I don't think anyone ever really used it.
So it might feasible to simply yank it. That said, just doing a prune
mode at ->release() time doesn't seem like such a hard task.

"prune mode" being...?

Basically what Jann posted, not doing any copy-back of data. Need to
verify if the bio unmapping is handled correctly, as some of those
will also copy when the end_io handling is invoked.

-- 
Jens Axboe