From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dennis Dalessandro Subject: Re: [PATCH 02/37] IB/rdmavt: Consolidate dma ops in rdmavt. Date: Thu, 10 Dec 2015 11:17:09 -0500 Message-ID: <20151210161708.GA13412@phlsvsds.ph.intel.com> References: <20151207204046.8144.18752.stgit@phlsvslse11.ph.intel.com> <20151207204305.8144.7038.stgit@phlsvslse11.ph.intel.com> <20151208060821.GD7313@leon.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Content-Disposition: inline In-Reply-To: <20151208060821.GD7313-2ukJVAZIZ/Y@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mike Marciniszyn , Ira Weiny List-Id: linux-rdma@vger.kernel.org On Tue, Dec 08, 2015 at 08:08:21AM +0200, Leon Romanovsky wrote: >On Mon, Dec 07, 2015 at 03:43:06PM -0500, Dennis Dalessandro wrote: >> + >> +#define BAD_DMA_ADDRESS ((u64)0) >What is the advantage in using directly u64 values instead of >pointers? You will get NULL and functions which return pointers >without need of casting. > >... >> +static u64 rvt_dma_map_single(struct ib_device *dev, void *cpu_addr, >> + size_t size, enum dma_data_direction direction) >> +{ >> + if (WARN_ON(!valid_dma_direction(direction))) >> + return BAD_DMA_ADDRESS; >> + >> + return (u64)cpu_addr; >> +} >An example of such function. Honestly I'm not really sure why it's done this way. We are just following the signature of the function in struct ib_dma_mapping_ops. -Denny -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html