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>

diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index 17c8e5d82681022383d657da550924d48d0d9289..bb69f8f90b3b47c441fde750c14d0a9b9a3a6da0 100644 (file)
--- 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);