IB/iser: Generalize fall_to_bounce_buf routine

Unaligned SG-lists may also happen for protection information.
Generalize bounce buffer routine to handle any iser_data_buf which may
be data and/or protection.

This patch does not change any functionality.

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

1 files changed, 29 insertions, 24 deletions

diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index a9335080ae69..2c3f4b144a1a 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -45,13 +45,19 @@
  * iser_start_rdma_unaligned_sg
  */
 static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
+                                        struct iser_data_buf *data,
+                                        struct iser_data_buf *data_copy,
                                         enum iser_data_dir cmd_dir)
 {
-        int dma_nents;
-        struct ib_device *dev;
+        struct ib_device *dev = iser_task->iser_conn->ib_conn->device->ib_device;
+        struct scatterlist *sgl = (struct scatterlist *)data->buf;
+        struct scatterlist *sg;
         char *mem = NULL;
-        struct iser_data_buf *data = &iser_task->data[cmd_dir];
-        unsigned long  cmd_data_len = data->data_len;
+        unsigned long  cmd_data_len = 0;
+        int dma_nents, i;
+
+        for_each_sg(sgl, sg, data->size, i)
+                cmd_data_len += ib_sg_dma_len(dev, sg);
 
         if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
                 mem = (void *)__get_free_pages(GFP_ATOMIC,
@@ -61,17 +67,16 @@ static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
 
         if (mem == NULL) {
                 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
-                         data->size,(int)cmd_data_len);
+                         data->size, (int)cmd_data_len);
                 return -ENOMEM;
         }
 
         if (cmd_dir == ISER_DIR_OUT) {
                 /* copy the unaligned sg the buffer which is used for RDMA */
-                struct scatterlist *sgl = (struct scatterlist *)data->buf;
-                struct scatterlist *sg;
                 int i;
                 char *p, *from;
 
+                sgl = (struct scatterlist *)data->buf;
                 p = mem;
                 for_each_sg(sgl, sg, data->size, i) {
                         from = kmap_atomic(sg_page(sg));
@@ -83,22 +88,19 @@ static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
                 }
         }
 
-        sg_init_one(&iser_task->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
-        iser_task->data_copy[cmd_dir].buf  =
-                &iser_task->data_copy[cmd_dir].sg_single;
-        iser_task->data_copy[cmd_dir].size = 1;
+        sg_init_one(&data_copy->sg_single, mem, cmd_data_len);
+        data_copy->buf = &data_copy->sg_single;
+        data_copy->size = 1;
+        data_copy->copy_buf = mem;
 
-        iser_task->data_copy[cmd_dir].copy_buf  = mem;
-
-        dev = iser_task->iser_conn->ib_conn->device->ib_device;
-        dma_nents = ib_dma_map_sg(dev,
-                                  &iser_task->data_copy[cmd_dir].sg_single,
-                                  1,
+        dma_nents = ib_dma_map_sg(dev, &data_copy->sg_single, 1,
                                   (cmd_dir == ISER_DIR_OUT) ?
                                   DMA_TO_DEVICE : DMA_FROM_DEVICE);
         BUG_ON(dma_nents == 0);
 
-        iser_task->data_copy[cmd_dir].dma_nents = dma_nents;
+        data_copy->dma_nents = dma_nents;
+        data_copy->data_len = cmd_data_len;
+
         return 0;
 }
 
@@ -341,11 +343,12 @@ void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
 
 static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
                               struct ib_device *ibdev,
+                              struct iser_data_buf *mem,
+                              struct iser_data_buf *mem_copy,
                               enum iser_data_dir cmd_dir,
                               int aligned_len)
 {
         struct iscsi_conn    *iscsi_conn = iser_task->iser_conn->iscsi_conn;
-        struct iser_data_buf *mem = &iser_task->data[cmd_dir];
 
         iscsi_conn->fmr_unalign_cnt++;
         iser_warn("rdma alignment violation (%d/%d aligned) or FMR not supported\n",
@@ -355,12 +358,12 @@ static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
                 iser_data_buf_dump(mem, ibdev);
 
         /* unmap the command data before accessing it */
-        iser_dma_unmap_task_data(iser_task, &iser_task->data[cmd_dir]);
+        iser_dma_unmap_task_data(iser_task, mem);
 
         /* allocate copy buf, if we are writing, copy the */
         /* unaligned scatterlist, dma map the copy        */
-        if (iser_start_rdma_unaligned_sg(iser_task, cmd_dir) != 0)
-                        return -ENOMEM;
+        if (iser_start_rdma_unaligned_sg(iser_task, mem, mem_copy, cmd_dir) != 0)
+                return -ENOMEM;
 
         return 0;
 }
@@ -388,7 +391,8 @@ int iser_reg_rdma_mem_fmr(struct iscsi_iser_task *iser_task,
 
         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
         if (aligned_len != mem->dma_nents) {
-                err = fall_to_bounce_buf(iser_task, ibdev,
+                err = fall_to_bounce_buf(iser_task, ibdev, mem,
+                                         &iser_task->data_copy[cmd_dir],
                                          cmd_dir, aligned_len);
                 if (err) {
                         iser_err("failed to allocate bounce buffer\n");
@@ -536,7 +540,8 @@ int iser_reg_rdma_mem_fastreg(struct iscsi_iser_task *iser_task,
 
         aligned_len = iser_data_buf_aligned_len(mem, ibdev);
         if (aligned_len != mem->dma_nents) {
-                err = fall_to_bounce_buf(iser_task, ibdev,
+                err = fall_to_bounce_buf(iser_task, ibdev, mem,
+                                         &iser_task->data_copy[cmd_dir],
                                          cmd_dir, aligned_len);
                 if (err) {
                         iser_err("failed to allocate bounce buffer\n");