Commit 59a6ee97 authored by Johannes Berg's avatar Johannes Berg Committed by Luca Coelho
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iwlwifi: pcie: avoid dma unmap/remap in crash dump 



DMA-API debug code pointed out that in this code path we
never check the return value of dma_map_page(), which could
fail.

However, we don't really even want to unmap/remap, we just
want to ensure that we can actually access the last version
of the data that the (now-dead) device may have written, so
only need to dma_sync_single_for_cpu() instead.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210819183728.5987f35883a2.I2d9ea5ecc69a5e5947b546fb15f33363a0595651@changeid


Signed-off-by: default avatarLuca Coelho <luciano.coelho@intel.com>
parent 40063f60

drivers/net/wireless/intel/iwlwifi/pcie/trans.c

+2 −6
Original line number Diff line number Diff line
@@ -2968,8 +2968,8 @@ static u32 iwl_trans_pcie_dump_rbs(struct iwl_trans *trans, 
		struct iwl_rx_mem_buffer *rxb = rxq->queue[i];

		struct iwl_fw_error_dump_rb *rb;



		dma_unmap_page(trans->dev, rxb->page_dma, max_len,

			       DMA_FROM_DEVICE);

		dma_sync_single_for_cpu(trans->dev, rxb->page_dma,

					max_len, DMA_FROM_DEVICE);



		rb_len += sizeof(**data) + sizeof(*rb) + max_len;
@@ -2978,10 +2978,6 @@ static u32 iwl_trans_pcie_dump_rbs(struct iwl_trans *trans, 
		rb = (void *)(*data)->data;

		rb->index = cpu_to_le32(i);

		memcpy(rb->data, page_address(rxb->page), max_len);

		/* remap the page for the free benefit */

		rxb->page_dma = dma_map_page(trans->dev, rxb->page,

					     rxb->offset, max_len,

					     DMA_FROM_DEVICE);



		*data = iwl_fw_error_next_data(*data);

	}