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Subject[PATCH 078/241] iwlwifi: handle DMA mapping failures
Date
3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

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

From: Johannes Berg <johannes.berg@intel.com>

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@hp.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[ 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@canonical.com>
---
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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