IB/iser: Use separate buffers for the login request/response

The driver counted on the transactional nature of iSCSI login/text
flows and used the same buffer for both the request and the response.
We also went further and did DMA mapping only once, with
DMA_FROM_DEVICE, which violates the DMA mapping API.  Fix that by
using different buffers, one for requests and one for responses, and
use the correct DMA mapping direction for each.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

3 files changed, 52 insertions, 15 deletions

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index db6f3ce9f3bf..2982a14a0557 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -257,7 +257,8 @@ struct iser_conn {
         struct list_head             conn_list;       /* entry in ig conn list */
 
         char                         *login_buf;
-        u64                          login_dma;
+        char                         *login_req_buf, *login_resp_buf;
+        u64                          login_req_dma, login_resp_dma;
         unsigned int                 rx_desc_head;
         struct iser_rx_desc          *rx_descs;
         struct ib_recv_wr            rx_wr[ISER_MIN_POSTED_RX];
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index f299de6b419b..a607542fc796 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -221,8 +221,14 @@ void iser_free_rx_descriptors(struct iser_conn *ib_conn)
         struct iser_device *device = ib_conn->device;
 
         if (ib_conn->login_buf) {
-                ib_dma_unmap_single(device->ib_device, ib_conn->login_dma,
-                        ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
+                if (ib_conn->login_req_dma)
+                        ib_dma_unmap_single(device->ib_device,
+                                ib_conn->login_req_dma,
+                                ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
+                if (ib_conn->login_resp_dma)
+                        ib_dma_unmap_single(device->ib_device,
+                                ib_conn->login_resp_dma,
+                                ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
                 kfree(ib_conn->login_buf);
         }
 
@@ -394,6 +400,7 @@ int iser_send_control(struct iscsi_conn *conn,
         unsigned long data_seg_len;
         int err = 0;
         struct iser_device *device;
+        struct iser_conn *ib_conn = iser_conn->ib_conn;
 
         /* build the tx desc regd header and add it to the tx desc dto */
         mdesc->type = ISCSI_TX_CONTROL;
@@ -409,9 +416,19 @@ int iser_send_control(struct iscsi_conn *conn,
                         iser_err("data present on non login task!!!\n");
                         goto send_control_error;
                 }
-                memcpy(iser_conn->ib_conn->login_buf, task->data,
+
+                ib_dma_sync_single_for_cpu(device->ib_device,
+                        ib_conn->login_req_dma, task->data_count,
+                        DMA_TO_DEVICE);
+
+                memcpy(iser_conn->ib_conn->login_req_buf, task->data,
                                                         task->data_count);
-                tx_dsg->addr    = iser_conn->ib_conn->login_dma;
+
+                ib_dma_sync_single_for_device(device->ib_device,
+                        ib_conn->login_req_dma, task->data_count,
+                        DMA_TO_DEVICE);
+
+                tx_dsg->addr    = iser_conn->ib_conn->login_req_dma;
                 tx_dsg->length  = task->data_count;
                 tx_dsg->lkey    = device->mr->lkey;
                 mdesc->num_sge = 2;
@@ -445,8 +462,8 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc,
         int rx_buflen, outstanding, count, err;
 
         /* differentiate between login to all other PDUs */
-        if ((char *)rx_desc == ib_conn->login_buf) {
-                rx_dma = ib_conn->login_dma;
+        if ((char *)rx_desc == ib_conn->login_resp_buf) {
+                rx_dma = ib_conn->login_resp_dma;
                 rx_buflen = ISER_RX_LOGIN_SIZE;
         } else {
                 rx_dma = rx_desc->dma_addr;
@@ -473,7 +490,7 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc,
          * for the posted rx bufs refcount to become zero handles everything   */
         conn->ib_conn->post_recv_buf_count--;
 
-        if (rx_dma == ib_conn->login_dma)
+        if (rx_dma == ib_conn->login_resp_dma)
                 return;
 
         outstanding = ib_conn->post_recv_buf_count;
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index ede1475bee09..e28877c4ce15 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -155,20 +155,39 @@ static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
 {
         struct iser_device      *device;
         struct ib_qp_init_attr  init_attr;
-        int                     ret = -ENOMEM;
+        int                     req_err, resp_err, ret = -ENOMEM;
         struct ib_fmr_pool_param params;
 
         BUG_ON(ib_conn->device == NULL);
 
         device = ib_conn->device;
 
-        ib_conn->login_buf = kmalloc(ISER_RX_LOGIN_SIZE, GFP_KERNEL);
+        ib_conn->login_buf = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN +
+                                        ISER_RX_LOGIN_SIZE, GFP_KERNEL);
         if (!ib_conn->login_buf)
                 goto out_err;
 
-        ib_conn->login_dma = ib_dma_map_single(ib_conn->device->ib_device,
-                                (void *)ib_conn->login_buf, ISER_RX_LOGIN_SIZE,
-                                DMA_FROM_DEVICE);
+        ib_conn->login_req_buf  = ib_conn->login_buf;
+        ib_conn->login_resp_buf = ib_conn->login_buf + ISCSI_DEF_MAX_RECV_SEG_LEN;
+
+        ib_conn->login_req_dma = ib_dma_map_single(ib_conn->device->ib_device,
+                                (void *)ib_conn->login_req_buf,
+                                ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
+
+        ib_conn->login_resp_dma = ib_dma_map_single(ib_conn->device->ib_device,
+                                (void *)ib_conn->login_resp_buf,
+                                ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
+
+        req_err  = ib_dma_mapping_error(device->ib_device, ib_conn->login_req_dma);
+        resp_err = ib_dma_mapping_error(device->ib_device, ib_conn->login_resp_dma);
+
+        if (req_err || resp_err) {
+                if (req_err)
+                        ib_conn->login_req_dma = 0;
+                if (resp_err)
+                        ib_conn->login_resp_dma = 0;
+                goto out_err;
+        }
 
         ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
                                     (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
@@ -658,11 +677,11 @@ int iser_post_recvl(struct iser_conn *ib_conn)
         struct ib_sge     sge;
         int ib_ret;
 
-        sge.addr   = ib_conn->login_dma;
+        sge.addr   = ib_conn->login_resp_dma;
         sge.length = ISER_RX_LOGIN_SIZE;
         sge.lkey   = ib_conn->device->mr->lkey;
 
-        rx_wr.wr_id   = (unsigned long)ib_conn->login_buf;
+        rx_wr.wr_id   = (unsigned long)ib_conn->login_resp_buf;
         rx_wr.sg_list = &sge;
         rx_wr.num_sge = 1;
         rx_wr.next    = NULL;