[PATCH 5.3 054/180] iwlwifi: pcie: fix support for transmitting SKBs with fraglist

Greg Kroah-Hartman
2019-12-16T18:09:17Z

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

commit 4f4925a7b23428d5719af5a2816586b2a0e6fd19 upstream.

When the implementation of SKBs with fraglist was sent upstream, a
merge-damage occurred and half the patch was not applied.

This causes problems in high-throughput situations with AX200 devices,
including low throughput and FW crashes.

Introduce the part that was missing from the original patch.

Fixes: 0044f1716c4d ("iwlwifi: pcie: support transmitting SKBs with fraglist")
Cc: stable@vger.kernel.org # 4.20+
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[ This patch was created by me, but the original author of this code
is Johannes, so his s-o-b is here and he's marked as the author of
the patch. ]
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

--- a/drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c
@@ -469,6 +469,7 @@ iwl_tfh_tfd *iwl_pcie_gen2_build_tx(stru
dma_addr_t tb_phys;
int len, tb1_len, tb2_len;
void *tb1_addr;
+ struct sk_buff *frag;

tb_phys = iwl_pcie_get_first_tb_dma(txq, idx);

@@ -517,6 +518,19 @@ iwl_tfh_tfd *iwl_pcie_gen2_build_tx(stru
if (iwl_pcie_gen2_tx_add_frags(trans, skb, tfd, out_meta))
goto out_err;

+ skb_walk_frags(skb, frag) {
+ tb_phys = dma_map_single(trans->dev, frag->data,
+ skb_headlen(frag), DMA_TO_DEVICE);
+ if (unlikely(dma_mapping_error(trans->dev, tb_phys)))
+ goto out_err;
+ iwl_pcie_gen2_set_tb(trans, tfd, tb_phys, skb_headlen(frag));
+ trace_iwlwifi_dev_tx_tb(trans->dev, skb,
+ frag->data,
+ skb_headlen(frag));
+ if (iwl_pcie_gen2_tx_add_frags(trans, frag, tfd, out_meta))
+ goto out_err;
+ }
+
return tfd;