[PATCH 078/241] iwlwifi: handle DMA mapping failures

[Herton Ronaldo Krzesinski]

3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit 7c34158231b2eda8dcbd297be2bb1559e69cb433 upstream.

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").

Reported-by: Shuah Khan <shuah.khan@xxxxxx>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
[ herton: adapt for 3.5:
  * code to patch is on iwl-trans-pcie-rx.c
  * first function patched was named iwlagn_rx_allocate
  * adjust context ]
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
---
 drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c |   23 ++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
index 5e18ff9..f774778 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
@@ -318,6 +318,14 @@ static void iwlagn_rx_allocate(struct iwl_trans *trans, gfp_t priority)
 		rxb->page_dma = 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! */
@@ -467,8 +475,19 @@ 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);
-- 
1.7.9.5

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