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 <[email protected]>
Tested-by: Christoph Hellwig <[email protected]>
---
drivers/infiniband/core/verbs.c | 107 ++++++++++++++++++++++++++++++++++++++++
include/rdma/ib_verbs.h | 44 +++++++++++++++++
2 files changed, 151 insertions(+)

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index e1f2c9887f3f..e18a8bce8130 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -1469,3 +1469,110 @@ 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,
+ unsigned 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,
+ unsigned 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);
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index c9abc8fec620..24bb87f16afb 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -739,6 +739,7 @@ enum ib_wc_opcode {
IB_WC_LSO,
IB_WC_LOCAL_INV,
IB_WC_FAST_REG_MR,
+ IB_WC_REG_MR,
IB_WC_MASKED_COMP_SWAP,
IB_WC_MASKED_FETCH_ADD,
/*
@@ -1030,6 +1031,7 @@ enum ib_wr_opcode {
IB_WR_RDMA_READ_WITH_INV,
IB_WR_LOCAL_INV,
IB_WR_FAST_REG_MR,
+ IB_WR_REG_MR,
IB_WR_MASKED_ATOMIC_CMP_AND_SWP,
IB_WR_MASKED_ATOMIC_FETCH_AND_ADD,
IB_WR_BIND_MW,
@@ -1163,6 +1165,18 @@ static inline struct ib_fast_reg_wr *fast_reg_wr(struct ib_send_wr *wr)
return container_of(wr, struct ib_fast_reg_wr, wr);
}

+struct ib_reg_wr {
+ struct ib_send_wr wr;
+ struct ib_mr *mr;
+ u32 key;
+ int access;
+};
+
+static inline struct ib_reg_wr *reg_wr(struct ib_send_wr *wr)
+{
+ return container_of(wr, struct ib_reg_wr, wr);
+}
+
struct ib_bind_mw_wr {
struct ib_send_wr wr;
struct ib_mw *mw;
@@ -1375,6 +1389,9 @@ struct ib_mr {
struct ib_uobject *uobject;
u32 lkey;
u32 rkey;
+ u64 iova;
+ u32 length;
+ unsigned int page_size;
atomic_t usecnt; /* count number of MWs */
};

@@ -1759,6 +1776,9 @@ struct ib_device {
struct ib_mr * (*alloc_mr)(struct ib_pd *pd,
enum ib_mr_type mr_type,
u32 max_num_sg);
+ int (*map_mr_sg)(struct ib_mr *mr,
+ struct scatterlist *sg,
+ unsigned int sg_nents);
struct ib_fast_reg_page_list * (*alloc_fast_reg_page_list)(struct ib_device *device,
int page_list_len);
void (*free_fast_reg_page_list)(struct ib_fast_reg_page_list *page_list);
@@ -3064,4 +3084,28 @@ struct net_device *ib_get_net_dev_by_params(struct ib_device *dev, u8 port,
u16 pkey, const union ib_gid *gid,
const struct sockaddr *addr);

+int ib_map_mr_sg(struct ib_mr *mr,
+ struct scatterlist *sg,
+ unsigned int sg_nents,
+ unsigned int page_size);
+
+static inline int
+ib_map_mr_sg_zbva(struct ib_mr *mr,
+ struct scatterlist *sg,
+ unsigned int sg_nents,
+ unsigned int page_size)
+{
+ int n;
+
+ n = ib_map_mr_sg(mr, sg, sg_nents, page_size);
+ mr->iova = 0;
+
+ return n;
+}
+
+int ib_sg_to_pages(struct ib_mr *mr,
+ struct scatterlist *sgl,
+ unsigned int sg_nents,
+ int (*set_page)(struct ib_mr *, u64));
+
#endif /* IB_VERBS_H */
--
1.8.4.3