IB/iser: Push the decision what memory key to use into fast_reg_mr routine

This is a preparation step for T10-PI offload support.  We prefer to
push the desicion of which mkey to use (global or fastreg) to
iser_fast_reg_mr.  We choose to do this since in T10-PI we may need to
register for protection buffers and in this case we wish to simplify
iser_fast_reg_mr instead of repeating the logic of which key to use.

This patch does not change any functionality.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Alex Tabachnik <alext@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 59 insertions, 42 deletions

diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index 6e9b7bcbc562..d25587e2f296 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -444,16 +444,40 @@ int iser_reg_rdma_mem_fmr(struct iscsi_iser_task *iser_task,
         return 0;
 }
 
-static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
-                            struct iser_conn *ib_conn,
+static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
                             struct iser_regd_buf *regd_buf,
-                            u32 offset, unsigned int data_size,
-                            unsigned int page_list_len)
+                            struct iser_data_buf *mem,
+                            struct ib_sge *sge)
 {
+        struct fast_reg_descriptor *desc = regd_buf->reg.mem_h;
+        struct iser_conn *ib_conn = iser_task->iser_conn->ib_conn;
+        struct iser_device *device = ib_conn->device;
+        struct ib_device *ibdev = device->ib_device;
         struct ib_send_wr fastreg_wr, inv_wr;
         struct ib_send_wr *bad_wr, *wr = NULL;
         u8 key;
-        int ret;
+        int ret, offset, size, plen;
+
+        /* if there a single dma entry, dma mr suffices */
+        if (mem->dma_nents == 1) {
+                struct scatterlist *sg = (struct scatterlist *)mem->buf;
+
+                sge->lkey = device->mr->lkey;
+                sge->addr   = ib_sg_dma_address(ibdev, &sg[0]);
+                sge->length  = ib_sg_dma_len(ibdev, &sg[0]);
+
+                iser_dbg("Single DMA entry: lkey=0x%x, addr=0x%llx, length=0x%x\n",
+                         sge->lkey, sge->addr, sge->length);
+                return 0;
+        }
+
+        plen = iser_sg_to_page_vec(mem, device->ib_device,
+                                   desc->data_frpl->page_list,
+                                   &offset, &size);
+        if (plen * SIZE_4K < size) {
+                iser_err("fast reg page_list too short to hold this SG\n");
+                return -EINVAL;
+        }
 
         if (!desc->valid) {
                 memset(&inv_wr, 0, sizeof(inv_wr));
@@ -472,9 +496,9 @@ static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
         fastreg_wr.opcode = IB_WR_FAST_REG_MR;
         fastreg_wr.wr.fast_reg.iova_start = desc->data_frpl->page_list[0] + offset;
         fastreg_wr.wr.fast_reg.page_list = desc->data_frpl;
-        fastreg_wr.wr.fast_reg.page_list_len = page_list_len;
+        fastreg_wr.wr.fast_reg.page_list_len = plen;
         fastreg_wr.wr.fast_reg.page_shift = SHIFT_4K;
-        fastreg_wr.wr.fast_reg.length = data_size;
+        fastreg_wr.wr.fast_reg.length = size;
         fastreg_wr.wr.fast_reg.rkey = desc->data_mr->rkey;
         fastreg_wr.wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
                                                IB_ACCESS_REMOTE_WRITE |
@@ -492,12 +516,9 @@ static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
         }
         desc->valid = false;
 
-        regd_buf->reg.mem_h = desc;
-        regd_buf->reg.lkey = desc->data_mr->lkey;
-        regd_buf->reg.rkey = desc->data_mr->rkey;
-        regd_buf->reg.va = desc->data_frpl->page_list[0] + offset;
-        regd_buf->reg.len = data_size;
-        regd_buf->reg.is_mr = 1;
+        sge->lkey = desc->data_mr->lkey;
+        sge->addr = desc->data_frpl->page_list[0] + offset;
+        sge->length = size;
 
         return ret;
 }
@@ -516,11 +537,10 @@ int iser_reg_rdma_mem_fastreg(struct iscsi_iser_task *iser_task,
         struct ib_device *ibdev = device->ib_device;
         struct iser_data_buf *mem = &iser_task->data[cmd_dir];
         struct iser_regd_buf *regd_buf = &iser_task->rdma_regd[cmd_dir];
-        struct fast_reg_descriptor *desc;
-        unsigned int data_size, page_list_len;
+        struct fast_reg_descriptor *desc = NULL;
+        struct ib_sge data_sge;
         int err, aligned_len;
         unsigned long flags;
-        u32 offset;
 
         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
         if (aligned_len != mem->dma_nents) {
@@ -533,41 +553,38 @@ int iser_reg_rdma_mem_fastreg(struct iscsi_iser_task *iser_task,
                 mem = &iser_task->data_copy[cmd_dir];
         }
 
-        /* if there a single dma entry, dma mr suffices */
-        if (mem->dma_nents == 1) {
-                struct scatterlist *sg = (struct scatterlist *)mem->buf;
-
-                regd_buf->reg.lkey = device->mr->lkey;
-                regd_buf->reg.rkey = device->mr->rkey;
-                regd_buf->reg.len  = ib_sg_dma_len(ibdev, &sg[0]);
-                regd_buf->reg.va   = ib_sg_dma_address(ibdev, &sg[0]);
-                regd_buf->reg.is_mr = 0;
-        } else {
+        if (mem->dma_nents != 1) {
                 spin_lock_irqsave(&ib_conn->lock, flags);
                 desc = list_first_entry(&ib_conn->fastreg.pool,
                                         struct fast_reg_descriptor, list);
                 list_del(&desc->list);
                 spin_unlock_irqrestore(&ib_conn->lock, flags);
-                page_list_len = iser_sg_to_page_vec(mem, device->ib_device,
-                                                    desc->data_frpl->page_list,
-                                                    &offset, &data_size);
-
-                if (page_list_len * SIZE_4K < data_size) {
-                        iser_err("fast reg page_list too short to hold this SG\n");
-                        err = -EINVAL;
-                        goto err_reg;
-                }
+                regd_buf->reg.mem_h = desc;
+        }
 
-                err = iser_fast_reg_mr(desc, ib_conn, regd_buf,
-                                       offset, data_size, page_list_len);
-                if (err)
-                        goto err_reg;
+        err = iser_fast_reg_mr(iser_task, regd_buf, mem, &data_sge);
+        if (err)
+                goto err_reg;
+
+        if (desc) {
+                regd_buf->reg.rkey = desc->data_mr->rkey;
+                regd_buf->reg.is_mr = 1;
+        } else {
+                regd_buf->reg.rkey = device->mr->rkey;
+                regd_buf->reg.is_mr = 0;
         }
 
+        regd_buf->reg.lkey = data_sge.lkey;
+        regd_buf->reg.va = data_sge.addr;
+        regd_buf->reg.len = data_sge.length;
+
         return 0;
 err_reg:
-        spin_lock_irqsave(&ib_conn->lock, flags);
-        list_add_tail(&desc->list, &ib_conn->fastreg.pool);
-        spin_unlock_irqrestore(&ib_conn->lock, flags);
+        if (desc) {
+                spin_lock_irqsave(&ib_conn->lock, flags);
+                list_add_tail(&desc->list, &ib_conn->fastreg.pool);
+                spin_unlock_irqrestore(&ib_conn->lock, flags);
+        }
+
         return err;
 }