iwlwifi: handle DMA mapping failures

The RX replenish code doesn't handle DMA mapping failures,
which will cause issues if there actually is a failure. This
was reported by Shuah Khan who found a DMA mapping framework
warning ("device driver failed to check map error").

Cc: stable@vger.kernel.org
Reported-by: Shuah Khan <shuah.khan@hp.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 21 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index 17c8e5d82681..bb69f8f90b3b 100644
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -321,6 +321,14 @@ static void iwl_rx_allocate(struct iwl_trans *trans, gfp_t priority)
                         dma_map_page(trans->dev, page, 0,
                                      PAGE_SIZE << trans_pcie->rx_page_order,
                                      DMA_FROM_DEVICE);
+                if (dma_mapping_error(trans->dev, rxb->page_dma)) {
+                        rxb->page = NULL;
+                        spin_lock_irqsave(&rxq->lock, flags);
+                        list_add(&rxb->list, &rxq->rx_used);
+                        spin_unlock_irqrestore(&rxq->lock, flags);
+                        __free_pages(page, trans_pcie->rx_page_order);
+                        return;
+                }
                 /* dma address must be no more than 36 bits */
                 BUG_ON(rxb->page_dma & ~DMA_BIT_MASK(36));
                 /* and also 256 byte aligned! */
@@ -488,8 +496,19 @@ static void iwl_rx_handle_rxbuf(struct iwl_trans *trans,
                         dma_map_page(trans->dev, rxb->page, 0,
                                      PAGE_SIZE << trans_pcie->rx_page_order,
                                      DMA_FROM_DEVICE);
-                list_add_tail(&rxb->list, &rxq->rx_free);
-                rxq->free_count++;
+                if (dma_mapping_error(trans->dev, rxb->page_dma)) {
+                        /*
+                         * free the page(s) as well to not break
+                         * the invariant that the items on the used
+                         * list have no page(s)
+                         */
+                        __free_pages(rxb->page, trans_pcie->rx_page_order);
+                        rxb->page = NULL;
+                        list_add_tail(&rxb->list, &rxq->rx_used);
+                } else {
+                        list_add_tail(&rxb->list, &rxq->rx_free);
+                        rxq->free_count++;
+                }
         } else
                 list_add_tail(&rxb->list, &rxq->rx_used);
         spin_unlock_irqrestore(&rxq->lock, flags);