isci: fix dma_unmap_sg usage

One bug and a cleanup:
1/ Fix cases where we were unmapping invalid addresses (smp requests were
   being unmapped)

[  604.662770] ------------[ cut here ]------------
[  604.668026] WARNING: at lib/dma-debug.c:800 check_unmap+0x418/0x740()
[  604.675315] Hardware name: SandyBridge Platform
[  604.680465] isci 0000:03:00.0: DMA-API: device driver tries to free an invalid DMA memory address

2/ The unmap routine is too large to be an inline function, and
   isci_request_io_request_get_next_sge is unused.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/drivers/scsi/isci/request.c b/drivers/scsi/isci/request.c
index f4fbca7b1fa3..395084955150 100644
--- a/drivers/scsi/isci/request.c
+++ b/drivers/scsi/isci/request.c
@@ -2930,7 +2930,22 @@ static void isci_request_io_request_complete(struct isci_host *isci_host,
                 break;
         }
 
-        isci_request_unmap_sgl(request, isci_host->pdev);
+        switch (task->task_proto) {
+        case SAS_PROTOCOL_SSP:
+                if (task->data_dir == DMA_NONE)
+                        break;
+                if (task->num_scatter == 0)
+                        /* 0 indicates a single dma address */
+                        dma_unmap_single(&isci_host->pdev->dev,
+                                         request->zero_scatter_daddr,
+                                         task->total_xfer_len, task->data_dir);
+                else  /* unmap the sgl dma addresses */
+                        dma_unmap_sg(&isci_host->pdev->dev, task->scatter,
+                                     request->num_sg_entries, task->data_dir);
+                break;
+        default:
+                break;
+        }
 
         /* Put the completed request on the correct list */
         isci_task_save_for_upper_layer_completion(isci_host, request, response,