RDMA/hns: Add mtr support for mixed multihop addressing
authorLijun Ou <oulijun@huawei.com>
Sat, 8 Jun 2019 06:46:08 +0000 (14:46 +0800)
committerDoug Ledford <dledford@redhat.com>
Thu, 20 Jun 2019 16:56:34 +0000 (12:56 -0400)
Currently, the MTT(memory translate table) design required a buffer
space must has the same hopnum, but the hip08 hw can support mixed
hopnum config in a buffer space.

This patch adds the MTR(memory translate region) design for supporting
mixed multihop.

Signed-off-by: Xi Wang <wangxi11@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
drivers/infiniband/hw/hns/hns_roce_device.h
drivers/infiniband/hw/hns/hns_roce_hem.c
drivers/infiniband/hw/hns/hns_roce_hem.h
drivers/infiniband/hw/hns/hns_roce_mr.c

index 303ea7c614a8d9e448f74dc3e176a4186780a838..ec2ed5cac3bc0de1bc165271719d9f0c4b42b2a4 100644 (file)
@@ -341,6 +341,29 @@ struct hns_roce_mtt {
        enum hns_roce_mtt_type  mtt_type;
 };
 
+struct hns_roce_buf_region {
+       int offset; /* page offset */
+       u32 count; /* page count*/
+       int hopnum; /* addressing hop num */
+};
+
+#define HNS_ROCE_MAX_BT_REGION 3
+#define HNS_ROCE_MAX_BT_LEVEL  3
+struct hns_roce_hem_list {
+       struct list_head root_bt;
+       /* link all bt dma mem by hop config */
+       struct list_head mid_bt[HNS_ROCE_MAX_BT_REGION][HNS_ROCE_MAX_BT_LEVEL];
+       struct list_head btm_bt; /* link all bottom bt in @mid_bt */
+       dma_addr_t root_ba; /* pointer to the root ba table */
+       int bt_pg_shift;
+};
+
+/* memory translate region */
+struct hns_roce_mtr {
+       struct hns_roce_hem_list hem_list;
+       int buf_pg_shift;
+};
+
 struct hns_roce_mw {
        struct ib_mw            ibmw;
        u32                     pdn;
@@ -1111,6 +1134,19 @@ void hns_roce_mtt_cleanup(struct hns_roce_dev *hr_dev,
 int hns_roce_buf_write_mtt(struct hns_roce_dev *hr_dev,
                           struct hns_roce_mtt *mtt, struct hns_roce_buf *buf);
 
+void hns_roce_mtr_init(struct hns_roce_mtr *mtr, int bt_pg_shift,
+                      int buf_pg_shift);
+int hns_roce_mtr_attach(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
+                       dma_addr_t **bufs, struct hns_roce_buf_region *regions,
+                       int region_cnt);
+void hns_roce_mtr_cleanup(struct hns_roce_dev *hr_dev,
+                         struct hns_roce_mtr *mtr);
+
+/* hns roce hw need current block and next block addr from mtt */
+#define MTT_MIN_COUNT   2
+int hns_roce_mtr_find(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
+                     int offset, u64 *mtt_buf, int mtt_max, u64 *base_addr);
+
 int hns_roce_init_pd_table(struct hns_roce_dev *hr_dev);
 int hns_roce_init_mr_table(struct hns_roce_dev *hr_dev);
 int hns_roce_init_eq_table(struct hns_roce_dev *hr_dev);
index 8490a86c3ef08b07a978767e13f08f27e2fc0633..d145e3ed21d455b56ad9dceefe5130e28f236702 100644 (file)
@@ -1157,3 +1157,463 @@ void hns_roce_cleanup_hem(struct hns_roce_dev *hr_dev)
                                           &hr_dev->mr_table.mtt_cqe_table);
        hns_roce_cleanup_hem_table(hr_dev, &hr_dev->mr_table.mtt_table);
 }
+
+struct roce_hem_item {
+       struct list_head list; /* link all hems in the same bt level */
+       struct list_head sibling; /* link all hems in last hop for mtt */
+       void *addr;
+       dma_addr_t dma_addr;
+       size_t count; /* max ba numbers */
+       int start; /* start buf offset in this hem */
+       int end; /* end buf offset in this hem */
+};
+
+static struct roce_hem_item *hem_list_alloc_item(struct hns_roce_dev *hr_dev,
+                                                  int start, int end,
+                                                  int count, bool exist_bt,
+                                                  int bt_level)
+{
+       struct roce_hem_item *hem;
+
+       hem = kzalloc(sizeof(*hem), GFP_KERNEL);
+       if (!hem)
+               return NULL;
+
+       if (exist_bt) {
+               hem->addr = dma_alloc_coherent(hr_dev->dev,
+                                                  count * BA_BYTE_LEN,
+                                                  &hem->dma_addr, GFP_KERNEL);
+               if (!hem->addr) {
+                       kfree(hem);
+                       return NULL;
+               }
+       }
+
+       hem->count = count;
+       hem->start = start;
+       hem->end = end;
+       INIT_LIST_HEAD(&hem->list);
+       INIT_LIST_HEAD(&hem->sibling);
+
+       return hem;
+}
+
+static void hem_list_free_item(struct hns_roce_dev *hr_dev,
+                              struct roce_hem_item *hem, bool exist_bt)
+{
+       if (exist_bt)
+               dma_free_coherent(hr_dev->dev, hem->count * BA_BYTE_LEN,
+                                 hem->addr, hem->dma_addr);
+       kfree(hem);
+}
+
+static void hem_list_free_all(struct hns_roce_dev *hr_dev,
+                             struct list_head *head, bool exist_bt)
+{
+       struct roce_hem_item *hem, *temp_hem;
+
+       list_for_each_entry_safe(hem, temp_hem, head, list) {
+               list_del(&hem->list);
+               hem_list_free_item(hr_dev, hem, exist_bt);
+       }
+}
+
+static void hem_list_link_bt(struct hns_roce_dev *hr_dev, void *base_addr,
+                            u64 table_addr)
+{
+       *(u64 *)(base_addr) = table_addr;
+}
+
+/* assign L0 table address to hem from root bt */
+static void hem_list_assign_bt(struct hns_roce_dev *hr_dev,
+                              struct roce_hem_item *hem, void *cpu_addr,
+                              u64 phy_addr)
+{
+       hem->addr = cpu_addr;
+       hem->dma_addr = (dma_addr_t)phy_addr;
+}
+
+static inline bool hem_list_page_is_in_range(struct roce_hem_item *hem,
+                                            int offset)
+{
+       return (hem->start <= offset && offset <= hem->end);
+}
+
+static struct roce_hem_item *hem_list_search_item(struct list_head *ba_list,
+                                                   int page_offset)
+{
+       struct roce_hem_item *hem, *temp_hem;
+       struct roce_hem_item *found = NULL;
+
+       list_for_each_entry_safe(hem, temp_hem, ba_list, list) {
+               if (hem_list_page_is_in_range(hem, page_offset)) {
+                       found = hem;
+                       break;
+               }
+       }
+
+       return found;
+}
+
+static bool hem_list_is_bottom_bt(int hopnum, int bt_level)
+{
+       /*
+        * hopnum    base address table levels
+        * 0            L0(buf)
+        * 1            L0 -> buf
+        * 2            L0 -> L1 -> buf
+        * 3            L0 -> L1 -> L2 -> buf
+        */
+       return bt_level >= (hopnum ? hopnum - 1 : hopnum);
+}
+
+/**
+ * calc base address entries num
+ * @hopnum: num of mutihop addressing
+ * @bt_level: base address table level
+ * @unit: ba entries per bt page
+ */
+static u32 hem_list_calc_ba_range(int hopnum, int bt_level, int unit)
+{
+       u32 step;
+       int max;
+       int i;
+
+       if (hopnum <= bt_level)
+               return 0;
+       /*
+        * hopnum  bt_level   range
+        * 1          0       unit
+        * ------------
+        * 2          0       unit * unit
+        * 2          1       unit
+        * ------------
+        * 3          0       unit * unit * unit
+        * 3          1       unit * unit
+        * 3          2       unit
+        */
+       step = 1;
+       max = hopnum - bt_level;
+       for (i = 0; i < max; i++)
+               step = step * unit;
+
+       return step;
+}
+
+/**
+ * calc the root ba entries which could cover all regions
+ * @regions: buf region array
+ * @region_cnt: array size of @regions
+ * @unit: ba entries per bt page
+ */
+int hns_roce_hem_list_calc_root_ba(const struct hns_roce_buf_region *regions,
+                                  int region_cnt, int unit)
+{
+       struct hns_roce_buf_region *r;
+       int total = 0;
+       int step;
+       int i;
+
+       for (i = 0; i < region_cnt; i++) {
+               r = (struct hns_roce_buf_region *)&regions[i];
+               if (r->hopnum > 1) {
+                       step = hem_list_calc_ba_range(r->hopnum, 1, unit);
+                       if (step > 0)
+                               total += (r->count + step - 1) / step;
+               } else {
+                       total += r->count;
+               }
+       }
+
+       return total;
+}
+
+static int hem_list_alloc_mid_bt(struct hns_roce_dev *hr_dev,
+                                const struct hns_roce_buf_region *r, int unit,
+                                int offset, struct list_head *mid_bt,
+                                struct list_head *btm_bt)
+{
+       struct roce_hem_item *hem_ptrs[HNS_ROCE_MAX_BT_LEVEL] = { NULL };
+       struct list_head temp_list[HNS_ROCE_MAX_BT_LEVEL];
+       struct roce_hem_item *cur, *pre;
+       const int hopnum = r->hopnum;
+       int start_aligned;
+       int distance;
+       int ret = 0;
+       int max_ofs;
+       int level;
+       u32 step;
+       int end;
+
+       if (hopnum <= 1)
+               return 0;
+
+       if (hopnum > HNS_ROCE_MAX_BT_LEVEL) {
+               dev_err(hr_dev->dev, "invalid hopnum %d!\n", hopnum);
+               return -EINVAL;
+       }
+
+       if (offset < r->offset) {
+               dev_err(hr_dev->dev, "invalid offset %d,min %d!\n",
+                       offset, r->offset);
+               return -EINVAL;
+       }
+
+       distance = offset - r->offset;
+       max_ofs = r->offset + r->count - 1;
+       for (level = 0; level < hopnum; level++)
+               INIT_LIST_HEAD(&temp_list[level]);
+
+       /* config L1 bt to last bt and link them to corresponding parent */
+       for (level = 1; level < hopnum; level++) {
+               cur = hem_list_search_item(&mid_bt[level], offset);
+               if (cur) {
+                       hem_ptrs[level] = cur;
+                       continue;
+               }
+
+               step = hem_list_calc_ba_range(hopnum, level, unit);
+               if (step < 1) {
+                       ret = -EINVAL;
+                       goto err_exit;
+               }
+
+               start_aligned = (distance / step) * step + r->offset;
+               end = min_t(int, start_aligned + step - 1, max_ofs);
+               cur = hem_list_alloc_item(hr_dev, start_aligned, end, unit,
+                                         true, level);
+               if (!cur) {
+                       ret = -ENOMEM;
+                       goto err_exit;
+               }
+               hem_ptrs[level] = cur;
+               list_add(&cur->list, &temp_list[level]);
+               if (hem_list_is_bottom_bt(hopnum, level))
+                       list_add(&cur->sibling, &temp_list[0]);
+
+               /* link bt to parent bt */
+               if (level > 1) {
+                       pre = hem_ptrs[level - 1];
+                       step = (cur->start - pre->start) / step * BA_BYTE_LEN;
+                       hem_list_link_bt(hr_dev, pre->addr + step,
+                                        cur->dma_addr);
+               }
+       }
+
+       list_splice(&temp_list[0], btm_bt);
+       for (level = 1; level < hopnum; level++)
+               list_splice(&temp_list[level], &mid_bt[level]);
+
+       return 0;
+
+err_exit:
+       for (level = 1; level < hopnum; level++)
+               hem_list_free_all(hr_dev, &temp_list[level], true);
+
+       return ret;
+}
+
+static int hem_list_alloc_root_bt(struct hns_roce_dev *hr_dev,
+                                 struct hns_roce_hem_list *hem_list, int unit,
+                                 const struct hns_roce_buf_region *regions,
+                                 int region_cnt)
+{
+       struct roce_hem_item *hem, *temp_hem, *root_hem;
+       struct list_head temp_list[HNS_ROCE_MAX_BT_REGION];
+       const struct hns_roce_buf_region *r;
+       struct list_head temp_root;
+       struct list_head temp_btm;
+       void *cpu_base;
+       u64 phy_base;
+       int ret = 0;
+       int offset;
+       int total;
+       int step;
+       int i;
+
+       r = &regions[0];
+       root_hem = hem_list_search_item(&hem_list->root_bt, r->offset);
+       if (root_hem)
+               return 0;
+
+       INIT_LIST_HEAD(&temp_root);
+       total = r->offset;
+       /* indicate to last region */
+       r = &regions[region_cnt - 1];
+       root_hem = hem_list_alloc_item(hr_dev, total, r->offset + r->count - 1,
+                                      unit, true, 0);
+       if (!root_hem)
+               return -ENOMEM;
+       list_add(&root_hem->list, &temp_root);
+
+       hem_list->root_ba = root_hem->dma_addr;
+
+       INIT_LIST_HEAD(&temp_btm);
+       for (i = 0; i < region_cnt; i++)
+               INIT_LIST_HEAD(&temp_list[i]);
+
+       total = 0;
+       for (i = 0; i < region_cnt && total < unit; i++) {
+               r = &regions[i];
+               if (!r->count)
+                       continue;
+
+               /* all regions's mid[x][0] shared the root_bt's trunk */
+               cpu_base = root_hem->addr + total * BA_BYTE_LEN;
+               phy_base = root_hem->dma_addr + total * BA_BYTE_LEN;
+
+               /* if hopnum is 0 or 1, cut a new fake hem from the root bt
+                * which's address share to all regions.
+                */
+               if (hem_list_is_bottom_bt(r->hopnum, 0)) {
+                       hem = hem_list_alloc_item(hr_dev, r->offset,
+                                                 r->offset + r->count - 1,
+                                                 r->count, false, 0);
+                       if (!hem) {
+                               ret = -ENOMEM;
+                               goto err_exit;
+                       }
+                       hem_list_assign_bt(hr_dev, hem, cpu_base, phy_base);
+                       list_add(&hem->list, &temp_list[i]);
+                       list_add(&hem->sibling, &temp_btm);
+                       total += r->count;
+               } else {
+                       step = hem_list_calc_ba_range(r->hopnum, 1, unit);
+                       if (step < 1) {
+                               ret = -EINVAL;
+                               goto err_exit;
+                       }
+                       /* if exist mid bt, link L1 to L0 */
+                       list_for_each_entry_safe(hem, temp_hem,
+                                         &hem_list->mid_bt[i][1], list) {
+                               offset = hem->start / step * BA_BYTE_LEN;
+                               hem_list_link_bt(hr_dev, cpu_base + offset,
+                                                hem->dma_addr);
+                               total++;
+                       }
+               }
+       }
+
+       list_splice(&temp_btm, &hem_list->btm_bt);
+       list_splice(&temp_root, &hem_list->root_bt);
+       for (i = 0; i < region_cnt; i++)
+               list_splice(&temp_list[i], &hem_list->mid_bt[i][0]);
+
+       return 0;
+
+err_exit:
+       for (i = 0; i < region_cnt; i++)
+               hem_list_free_all(hr_dev, &temp_list[i], false);
+
+       hem_list_free_all(hr_dev, &temp_root, true);
+
+       return ret;
+}
+
+/* construct the base address table and link them by address hop config */
+int hns_roce_hem_list_request(struct hns_roce_dev *hr_dev,
+                             struct hns_roce_hem_list *hem_list,
+                             const struct hns_roce_buf_region *regions,
+                             int region_cnt)
+{
+       const struct hns_roce_buf_region *r;
+       int ofs, end;
+       int ret = 0;
+       int unit;
+       int i;
+
+       if (region_cnt > HNS_ROCE_MAX_BT_REGION) {
+               dev_err(hr_dev->dev, "invalid region region_cnt %d!\n",
+                       region_cnt);
+               return -EINVAL;
+       }
+
+       unit = (1 << hem_list->bt_pg_shift) / BA_BYTE_LEN;
+       for (i = 0; i < region_cnt; i++) {
+               r = &regions[i];
+               if (!r->count)
+                       continue;
+
+               end = r->offset + r->count;
+               for (ofs = r->offset; ofs < end; ofs += unit) {
+                       ret = hem_list_alloc_mid_bt(hr_dev, r, unit, ofs,
+                                                   hem_list->mid_bt[i],
+                                                   &hem_list->btm_bt);
+                       if (ret) {
+                               dev_err(hr_dev->dev,
+                                       "alloc hem trunk fail ret=%d!\n", ret);
+                               goto err_alloc;
+                       }
+               }
+       }
+
+       ret = hem_list_alloc_root_bt(hr_dev, hem_list, unit, regions,
+                                    region_cnt);
+       if (ret)
+               dev_err(hr_dev->dev, "alloc hem root fail ret=%d!\n", ret);
+       else
+               return 0;
+
+err_alloc:
+       hns_roce_hem_list_release(hr_dev, hem_list);
+
+       return ret;
+}
+
+void hns_roce_hem_list_release(struct hns_roce_dev *hr_dev,
+                              struct hns_roce_hem_list *hem_list)
+{
+       int i, j;
+
+       for (i = 0; i < HNS_ROCE_MAX_BT_REGION; i++)
+               for (j = 0; j < HNS_ROCE_MAX_BT_LEVEL; j++)
+                       hem_list_free_all(hr_dev, &hem_list->mid_bt[i][j],
+                                         j != 0);
+
+       hem_list_free_all(hr_dev, &hem_list->root_bt, true);
+       INIT_LIST_HEAD(&hem_list->btm_bt);
+       hem_list->root_ba = 0;
+}
+
+void hns_roce_hem_list_init(struct hns_roce_hem_list *hem_list,
+                           int bt_page_order)
+{
+       int i, j;
+
+       INIT_LIST_HEAD(&hem_list->root_bt);
+       INIT_LIST_HEAD(&hem_list->btm_bt);
+       for (i = 0; i < HNS_ROCE_MAX_BT_REGION; i++)
+               for (j = 0; j < HNS_ROCE_MAX_BT_LEVEL; j++)
+                       INIT_LIST_HEAD(&hem_list->mid_bt[i][j]);
+
+       hem_list->bt_pg_shift = bt_page_order;
+}
+
+void *hns_roce_hem_list_find_mtt(struct hns_roce_dev *hr_dev,
+                                struct hns_roce_hem_list *hem_list,
+                                int offset, int *mtt_cnt, u64 *phy_addr)
+{
+       struct list_head *head = &hem_list->btm_bt;
+       struct roce_hem_item *hem, *temp_hem;
+       void *cpu_base = NULL;
+       u64 phy_base = 0;
+       int nr = 0;
+
+       list_for_each_entry_safe(hem, temp_hem, head, sibling) {
+               if (hem_list_page_is_in_range(hem, offset)) {
+                       nr = offset - hem->start;
+                       cpu_base = hem->addr + nr * BA_BYTE_LEN;
+                       phy_base = hem->dma_addr + nr * BA_BYTE_LEN;
+                       nr = hem->end + 1 - offset;
+                       break;
+               }
+       }
+
+       if (mtt_cnt)
+               *mtt_cnt = nr;
+
+       if (phy_addr)
+               *phy_addr = phy_base;
+
+       return cpu_base;
+}
index d9d668992e4944d800dfee47fd9c2bbf0e831824..e865fc8a18a748f1f63b3903f1bac1b3f0cba0ab 100644 (file)
@@ -133,6 +133,20 @@ int hns_roce_calc_hem_mhop(struct hns_roce_dev *hr_dev,
                           struct hns_roce_hem_mhop *mhop);
 bool hns_roce_check_whether_mhop(struct hns_roce_dev *hr_dev, u32 type);
 
+void hns_roce_hem_list_init(struct hns_roce_hem_list *hem_list,
+                           int bt_page_order);
+int hns_roce_hem_list_calc_root_ba(const struct hns_roce_buf_region *regions,
+                                  int region_cnt, int unit);
+int hns_roce_hem_list_request(struct hns_roce_dev *hr_dev,
+                             struct hns_roce_hem_list *hem_list,
+                             const struct hns_roce_buf_region *regions,
+                             int region_cnt);
+void hns_roce_hem_list_release(struct hns_roce_dev *hr_dev,
+                              struct hns_roce_hem_list *hem_list);
+void *hns_roce_hem_list_find_mtt(struct hns_roce_dev *hr_dev,
+                                struct hns_roce_hem_list *hem_list,
+                                int offset, int *mtt_cnt, u64 *phy_addr);
+
 static inline void hns_roce_hem_first(struct hns_roce_hem *hem,
                                      struct hns_roce_hem_iter *iter)
 {
index 38ed4ac741b57c726b3081dc291d67604a6c2853..6db0dae18ab716f89400c0b3ba821c60ebbb1671 100644 (file)
@@ -1496,3 +1496,121 @@ int hns_roce_dealloc_mw(struct ib_mw *ibmw)
 
        return 0;
 }
+
+void hns_roce_mtr_init(struct hns_roce_mtr *mtr, int bt_pg_shift,
+                      int buf_pg_shift)
+{
+       hns_roce_hem_list_init(&mtr->hem_list, bt_pg_shift);
+       mtr->buf_pg_shift = buf_pg_shift;
+}
+
+void hns_roce_mtr_cleanup(struct hns_roce_dev *hr_dev,
+                         struct hns_roce_mtr *mtr)
+{
+       hns_roce_hem_list_release(hr_dev, &mtr->hem_list);
+}
+EXPORT_SYMBOL_GPL(hns_roce_mtr_cleanup);
+
+static int hns_roce_write_mtr(struct hns_roce_dev *hr_dev,
+                             struct hns_roce_mtr *mtr, dma_addr_t *bufs,
+                             struct hns_roce_buf_region *r)
+{
+       int offset;
+       int count;
+       int npage;
+       u64 *mtts;
+       int end;
+       int i;
+
+       offset = r->offset;
+       end = offset + r->count;
+       npage = 0;
+       while (offset < end) {
+               mtts = hns_roce_hem_list_find_mtt(hr_dev, &mtr->hem_list,
+                                                 offset, &count, NULL);
+               if (!mtts)
+                       return -ENOBUFS;
+
+               /* Save page addr, low 12 bits : 0 */
+               for (i = 0; i < count; i++) {
+                       if (hr_dev->hw_rev == HNS_ROCE_HW_VER1)
+                               mtts[i] = cpu_to_le64(bufs[npage] >>
+                                                       PAGE_ADDR_SHIFT);
+                       else
+                               mtts[i] = cpu_to_le64(bufs[npage]);
+
+                       npage++;
+               }
+               offset += count;
+       }
+
+       return 0;
+}
+
+int hns_roce_mtr_attach(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
+                       dma_addr_t **bufs, struct hns_roce_buf_region *regions,
+                       int region_cnt)
+{
+       struct hns_roce_buf_region *r;
+       int ret;
+       int i;
+
+       ret = hns_roce_hem_list_request(hr_dev, &mtr->hem_list, regions,
+                                       region_cnt);
+       if (ret)
+               return ret;
+
+       for (i = 0; i < region_cnt; i++) {
+               r = &regions[i];
+               ret = hns_roce_write_mtr(hr_dev, mtr, bufs[i], r);
+               if (ret) {
+                       dev_err(hr_dev->dev,
+                               "write mtr[%d/%d] err %d,offset=%d.\n",
+                               i, region_cnt, ret,  r->offset);
+                       goto err_write;
+               }
+       }
+
+       return 0;
+
+err_write:
+       hns_roce_hem_list_release(hr_dev, &mtr->hem_list);
+
+       return ret;
+}
+
+int hns_roce_mtr_find(struct hns_roce_dev *hr_dev, struct hns_roce_mtr *mtr,
+                     int offset, u64 *mtt_buf, int mtt_max, u64 *base_addr)
+{
+       u64 *mtts = mtt_buf;
+       int mtt_count;
+       int total = 0;
+       u64 *addr;
+       int npage;
+       int left;
+
+       if (mtts == NULL || mtt_max < 1)
+               goto done;
+
+       left = mtt_max;
+       while (left > 0) {
+               mtt_count = 0;
+               addr = hns_roce_hem_list_find_mtt(hr_dev, &mtr->hem_list,
+                                                 offset + total,
+                                                 &mtt_count, NULL);
+               if (!addr || !mtt_count)
+                       goto done;
+
+               npage = min(mtt_count, left);
+               memcpy(&mtts[total], addr, BA_BYTE_LEN * npage);
+               left -= npage;
+               total += npage;
+       }
+
+done:
+       if (base_addr)
+               *base_addr = mtr->hem_list.root_ba;
+
+       return total;
+}
+EXPORT_SYMBOL_GPL(hns_roce_mtr_find);