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See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 01, 2020 at 03:37:09PM +0300, Konstantin Khlebnikov wrote: > Add flag for marking bio-based queues which support REQ_NOWAIT. > Set for all request based (mq) devices. > > Stacking device should set it after blk_set_stacking_limits() if method > make_request() itself doesn't delay requests or handles REQ_NOWAIT. I don't think this belongs into the queue limits. For example a stacking driver that always defers requests to a workqueue can support REQ_NOWAIT entirely independent of the underlying devices. I think this just needs to be a simple queue flag.