[PATCH 3.16 182/306] net/mlx5: Avoid passing dma address 0 to firmware

Ben Hutchings
2017-02-15T23:40:29Z

From: Noa Osherovich <noaos@mellanox.com>

commit 6b276190c50a12511d889d9079ffb901ff94a822 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
.../net/ethernet/mellanox/mlx5/core/pagealloc.c | 26 +++++++++++++++-------
1 file changed, 18 insertions(+), 8 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -243,6 +243,7 @@ static void free_4k(struct mlx5_core_dev
static int alloc_system_page(struct mlx5_core_dev *dev, u16 func_id)
{
struct page *page;
+ u64 zero_addr = 1;
u64 addr;
int err;

@@ -251,26 +252,35 @@ static int alloc_system_page(struct mlx5
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;
}