On Tue, Feb 07, 2017 at 02:32:15PM +0530, Anup Patel wrote: > On Tue, Feb 7, 2017 at 1:57 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > > On Tue, Feb 7, 2017 at 12:16 AM, Anup Patel <anup.patel@xxxxxxxxxxxx> wrote: > >> The DMAENGINE framework assumes that if PQ offload is supported by a > >> DMA device then all 256 PQ coefficients are supported. This assumption > >> does not hold anymore because we now have BCM-SBA-RAID offload engine > >> which supports PQ offload with limited number of PQ coefficients. > >> > >> This patch extends async_tx APIs to handle DMA devices with support > >> for fewer PQ coefficients. > >> > >> Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx> > >> Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx> > > > > I don't like this approach. Define an interface for md to query the > > offload engine once at the beginning of time. We should not be adding > > any new extensions to async_tx. > > Even if we do capability checks in Linux MD, we still need a way > for DMAENGINE drivers to advertise number of PQ coefficients > handled by the HW. If the question is only for advertising caps, then why not do as done for dma_get_slave_caps(). you can add dma_get_pq_caps() so that clients (md) in this case would know the HW capability. > I agree capability checks should be done once in Linux MD but I don't > see why this has to be part of BCM-SBA-RAID driver patches. We need > separate patchsets to address limitations of async_tx framework. > > Regards, > Anup -- ~Vinod
