On 9/5/18 1:56 PM, Christoph Hellwig wrote: > On Wed, Sep 05, 2018 at 01:45:04PM -0600, Jens Axboe wrote: >> The point is that the caller doesn't necessarily know where the bio >> will end up, hence the caller can't fully check if the whole stack >> supports P2P. > > The caller must necessarily know where the bio will end up, as for P2P > support we need to query if the bio target is P2P capable vs the > source of the P2P memory. Then what's the point of having the check at all? -- Jens Axboe