On 12/14/2017 11:13 PM, Bart Van Assche wrote: > On Tue, 2017-12-12 at 09:57 +0100, Hannes Reinecke wrote: >> With the current design we're waiting for all async probes to >> finish when removing any sd device. >> This might lead to a livelock where the 'remove' call is blocking >> for any probe calls to finish, and the probe calls are waiting for >> a response, which will never be processes as the thread handling >> the responses is waiting for the remove call to finish. >> Which is completely pointless as we only _really_ care for the >> probe on _this_ device to be completed; any other probing can >> happily continue for all we care. >> So save the async probing cookie in the structure and only wait >> if this specific probe is still active. > > From async_synchronize_cookie_domain(): > > wait_event(async_done, lowest_in_progress(domain) >= cookie); > > So async_synchronize_cookie_domain() also waits for multiple asynchronous > probes to finish. Does this patch have any advantages over the patch I > posted (https://marc.info/?l=linux-scsi&m=151275368714540)? > Correct, it waits for all _previous_ entries to complete. But this was precisely the point; previous entries (should) have all necessary information to complete (they probably only have been scheduled out for some reason), so a
The main advantage is that the change to make it work is relatively simple. (And doesn't change the interface; something we as poor distribution developer have to worry about...) Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
