From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH 02/13] IB/core: allow passing mapping an offset into the SG in ib_map_mr_sg Date: Sun, 28 Feb 2016 16:57:59 +0200 Message-ID: <56D30AF7.1060205@dev.mellanox.co.il> References: <1456596631-19418-1-git-send-email-hch@lst.de> <1456596631-19418-3-git-send-email-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1456596631-19418-3-git-send-email-hch-jcswGhMUV9g@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Hellwig , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org, sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, target-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org > @@ -1593,6 +1592,7 @@ EXPORT_SYMBOL(ib_map_mr_sg); > * @mr: memory region > * @sgl: dma mapped scatterlist > * @sg_nents: number of entries in sg > + * @sg_offset: offset in byes into sg > * @set_page: driver page assignment function pointer > * > * Core service helper for drivers to convert the largest > @@ -1603,10 +1603,8 @@ EXPORT_SYMBOL(ib_map_mr_sg); > * Returns the number of sg elements that were assigned to > * a page vector. > */ > -int ib_sg_to_pages(struct ib_mr *mr, > - struct scatterlist *sgl, > - int sg_nents, > - int (*set_page)(struct ib_mr *, u64)) > +int ib_sg_to_pages(struct ib_mr *mr, struct scatterlist *sgl, int sg_nents, > + unsigned int sg_offset, int (*set_page)(struct ib_mr *, u64)) > { > struct scatterlist *sg; > u64 last_end_dma_addr = 0; > @@ -1618,8 +1616,8 @@ int ib_sg_to_pages(struct ib_mr *mr, > mr->length = 0; > > for_each_sg(sgl, sg, sg_nents, i) { > - u64 dma_addr = sg_dma_address(sg); > - unsigned int dma_len = sg_dma_len(sg); > + u64 dma_addr = sg_dma_address(sg) + sg_offset; > + unsigned int dma_len = sg_dma_len(sg) - sg_offset; > u64 end_dma_addr = dma_addr + dma_len; > u64 page_addr = dma_addr & page_mask; > > @@ -1652,6 +1650,8 @@ next_page: > mr->length += dma_len; > last_end_dma_addr = end_dma_addr; > last_page_off = end_dma_addr & ~page_mask; > + > + sg_offset = 0; > } This looks wrong... The SG offset should not be taken into account in the address translation vector that is given to the HW. The sg_offset needs to be accounted in the mr->iova: mr->iova = sg_dma_address(&sgl[0]) + sg_offset; I think the page mappings should stay as the are. -- 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