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Subject[PATCH 3.4 92/99] iwlwifi: handle DMA mapping failures
Date
3.4-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>
[bwh: Backported to 3.2:
- Adjust filename, context, indentation
- Use bus(trans) instead of trans where necessary
- Use hw_params(trans).rx_page_order instead of trans_pcie->rx_page_order]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[wujg: Backported to 3.4:
- Adjust context
- Use trans instead of bus(trans)
- Use hw_params(trans).rx_page_order instead of trans_pcie->rx_page_order]
Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
@@ -315,6 +315,14 @@ static void iwlagn_rx_allocate(struct iw
rxb->page_dma = dma_map_page(trans->dev, page, 0,
PAGE_SIZE << hw_params(trans).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, hw_params(trans).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! */
@@ -450,8 +458,19 @@ static void iwl_rx_handle_rxbuf(struct i
dma_map_page(trans->dev, rxb->page, 0,
PAGE_SIZE << hw_params(trans).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, hw_params(trans).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);



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