net/mlx5: Avoid passing dma address 0 to firmware

Currently the firmware can't work with a page with dma address 0.
Passing such an address to the firmware will cause the give_pages
command to fail.

To avoid this, in case we get a 0 dma address of a page from the
dma engine, we avoid passing it to FW by remapping to get an address
other than 0.

Fixes: bf0bf77f6519 ('mlx5: Support communicating arbitrary host...')
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 8 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
index cc4fd61914d3..a57d5a81eb05 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -209,6 +209,7 @@ static void free_4k(struct mlx5_core_dev *dev, u64 addr)
 static int alloc_system_page(struct mlx5_core_dev *dev, u16 func_id)
 {
         struct page *page;
+        u64 zero_addr = 1;
         u64 addr;
         int err;
         int nid = dev_to_node(&dev->pdev->dev);
@@ -218,26 +219,35 @@ static int alloc_system_page(struct mlx5_core_dev *dev, u16 func_id)
                 mlx5_core_warn(dev, "failed to allocate page\n");
                 return -ENOMEM;
         }
+map:
         addr = dma_map_page(&dev->pdev->dev, page, 0,
                             PAGE_SIZE, DMA_BIDIRECTIONAL);
         if (dma_mapping_error(&dev->pdev->dev, addr)) {
                 mlx5_core_warn(dev, "failed dma mapping page\n");
                 err = -ENOMEM;
-                goto out_alloc;
+                goto err_mapping;
         }
+
+        /* Firmware doesn't support page with physical address 0 */
+        if (addr == 0) {
+                zero_addr = addr;
+                goto map;
+        }
+
         err = insert_page(dev, addr, page, func_id);
         if (err) {
                 mlx5_core_err(dev, "failed to track allocated page\n");
-                goto out_mapping;
+                dma_unmap_page(&dev->pdev->dev, addr, PAGE_SIZE,
+                               DMA_BIDIRECTIONAL);
         }
 
-        return 0;
-
-out_mapping:
-        dma_unmap_page(&dev->pdev->dev, addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
+err_mapping:
+        if (err)
+                __free_page(page);
 
-out_alloc:
-        __free_page(page);
+        if (zero_addr == 0)
+                dma_unmap_page(&dev->pdev->dev, zero_addr, PAGE_SIZE,
+                               DMA_BIDIRECTIONAL);
 
         return err;
 }