From 4c67e2bfc8b7121d51434362fa7c2d012f8bcf1b Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Tue, 13 Oct 2015 19:11:24 +0300 Subject: IB/core: Introduce new fast registration API The new fast registration verb ib_map_mr_sg receives a scatterlist and converts it to a page list under the verbs API thus hiding the specific HW mapping details away from the consumer. The provider drivers are provided with a generic helper ib_sg_to_pages that converts a scatterlist into a vector of page addresses. The drivers can still perform any HW specific page address setting by passing a set_page function pointer which will be invoked for each page address. This allows drivers to avoid keeping a shadow page vectors and convert them to HW specific translations by doing extra copies. This API will allow ULPs to remove the duplicated code of constructing a page vector from a given sg list. The send work request ib_reg_wr also shrinks as it will contain only mr, key and access flags in addition. Signed-off-by: Sagi Grimberg Tested-by: Christoph Hellwig Signed-off-by: Doug Ledford --- drivers/infiniband/core/verbs.c | 107 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c index 46d97f09fbae..5673df061213 100644 --- a/drivers/infiniband/core/verbs.c +++ b/drivers/infiniband/core/verbs.c @@ -1496,3 +1496,110 @@ int ib_check_mr_status(struct ib_mr *mr, u32 check_mask, mr->device->check_mr_status(mr, check_mask, mr_status) : -ENOSYS; } EXPORT_SYMBOL(ib_check_mr_status); + +/** + * ib_map_mr_sg() - Map the largest prefix of a dma mapped SG list + * and set it the memory region. + * @mr: memory region + * @sg: dma mapped scatterlist + * @sg_nents: number of entries in sg + * @page_size: page vector desired page size + * + * Constraints: + * - The first sg element is allowed to have an offset. + * - Each sg element must be aligned to page_size (or physically + * contiguous to the previous element). In case an sg element has a + * non contiguous offset, the mapping prefix will not include it. + * - The last sg element is allowed to have length less than page_size. + * - If sg_nents total byte length exceeds the mr max_num_sge * page_size + * then only max_num_sg entries will be mapped. + * + * Returns the number of sg elements that were mapped to the memory region. + * + * After this completes successfully, the memory region + * is ready for registration. + */ +int ib_map_mr_sg(struct ib_mr *mr, + struct scatterlist *sg, + int sg_nents, + unsigned int page_size) +{ + if (unlikely(!mr->device->map_mr_sg)) + return -ENOSYS; + + mr->page_size = page_size; + + return mr->device->map_mr_sg(mr, sg, sg_nents); +} +EXPORT_SYMBOL(ib_map_mr_sg); + +/** + * ib_sg_to_pages() - Convert the largest prefix of a sg list + * to a page vector + * @mr: memory region + * @sgl: dma mapped scatterlist + * @sg_nents: number of entries in sg + * @set_page: driver page assignment function pointer + * + * Core service helper for drivers to covert the largest + * prefix of given sg list to a page vector. The sg list + * prefix converted is the prefix that meet the requirements + * of 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)) +{ + struct scatterlist *sg; + u64 last_end_dma_addr = 0, last_page_addr = 0; + unsigned int last_page_off = 0; + u64 page_mask = ~((u64)mr->page_size - 1); + int i; + + mr->iova = sg_dma_address(&sgl[0]); + 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 end_dma_addr = dma_addr + dma_len; + u64 page_addr = dma_addr & page_mask; + + if (i && page_addr != dma_addr) { + if (last_end_dma_addr != dma_addr) { + /* gap */ + goto done; + + } else if (last_page_off + dma_len <= mr->page_size) { + /* chunk this fragment with the last */ + mr->length += dma_len; + last_end_dma_addr += dma_len; + last_page_off += dma_len; + continue; + } else { + /* map starting from the next page */ + page_addr = last_page_addr + mr->page_size; + dma_len -= mr->page_size - last_page_off; + } + } + + do { + if (unlikely(set_page(mr, page_addr))) + goto done; + page_addr += mr->page_size; + } while (page_addr < end_dma_addr); + + mr->length += dma_len; + last_end_dma_addr = end_dma_addr; + last_page_addr = end_dma_addr & page_mask; + last_page_off = end_dma_addr & ~page_mask; + } + +done: + return i; +} +EXPORT_SYMBOL(ib_sg_to_pages); -- cgit v1.2.3