On 10/28/2013 02:48 AM, Christoph Hellwig wrote: > On Sun, Oct 27, 2013 at 10:29:25PM +0000, Jens Axboe wrote: >> On Sat, Oct 26 2013, Christoph Hellwig wrote: >>> I think this variant of the patch from Alexander should fix the issue >>> in a minimally invasive way. Longer term I'd prefer to use q->flush_rq >>> like in the non-mq case by copying over the context and tag information. >> >> This one is pretty simple, we could definitely use it as a band aid. I >> too would greatly prefer using the static ->flush_rq instead. Just have >> it marked to bypass most of the free logic. > > We already bypass the free logical by setting and end_io callback for > a while, similar to what the old code does. Maybe it's not all that > hard to prealloc the request, let me give a sping. Using the static > allocated one will be hard due to the driver-specific extra data, > though.
It's not that I think the existing patch is THAT bad, it fits in alright with the reserved tagging and works regardless of whether a driver uses reserved tags or not. And it does have the upside of not requiring special checks or logic for this special non-tagged request that using the preallocated would might need. >> I'll add this one. > > Gimme another day or so to figure this out. OK, holding off. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
