On Mon, Aug 21, 2017 at 12:06:57PM +0300, Yishai Hadas wrote: > On 8/17/2017 9:03 PM, Jason Gunthorpe wrote: > >On Thu, Aug 17, 2017 at 08:39:32PM +0300, Leon Romanovsky wrote: > >>On Thu, Aug 17, 2017 at 11:33:20AM -0600, Jason Gunthorpe wrote: > >>>On Thu, Aug 17, 2017 at 04:36:38PM +0300, Yishai Hadas wrote: > >>>>From: Leon Romanovsky <leonro@xxxxxxxxxxxx> > >>>> > >>>>The returned UAR pointer is actually void ** and points to whole > >>>>UAR database. > >>>> > >>>>Because user is not supposed to access it and expected to use > >>>>the CQ doorbell, we will return uar[0] (CQ doorbell) directly > >>>>and eliminate the following logic in the applications: > >>>> > >>>>uint64_t cq_db_reg = (uint64_t *)(((uint64_t)(uint64_t *)rxq->cq_uar) + > >>>> MLX5_CQ_DOORBELL; > >>> > >>>NAK, at least, as is.. > >>> > >>>This changes the ABI and mlx5dv is a public interface now, so you have > >>>to do it properly. > >>> > >>>Looking at it, my advice is to rev the symbol version of > >>>mlx5dv_init_obj and consider providing a compat symbol. > >>> > >>>Also, you need to change the name of the 'uar' field: > >>> > >>>>- cq_out->uar = mctx->uar; > >>>>+ cq_out->uar = mctx->uar[0]; > >>> > >>>To something else, to make it clear, which of the two ABIs the > >>>application code is coded to - for a change like this, you *MUST* > >>>force old apps to have a compile failure. > >> > >>I know exactly who coded on top of this interface. They are the ones who > >>asked for this change and they are fully understand the implications, > >>inability to work with this interface on "old" libraries. > > > >I don't care who they are - you need to follow sane ABI rules if you > >are pushing public shared libraries into distros. This is not negotiable. > > > > There is no ABI/API change but just a bug fix in mlx5 driver. > The API talked about void* but by mistake the mlx5 code returned void**, > this patch fixes that. The commit message is garbage then. Is there existing code out there that uses cq_out->uar and works properly today? Yes or No? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
