path: root/Makefile
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authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2016-12-21 11:28:49 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-09 08:07:53 +0100
commit9f11a0ab6a9650de4b458b2a8759a32c2e4e89f0 (patch)
tree189189bd4310cf05e285dc967fef05d2e5a833bf /Makefile
parentd85727365859108cbcf832c2b3c38358ddc7638b (diff)
net: mvpp2: fix dma unmapping of TX buffers for fragments
commit 8354491c9d5b06709384cea91d13019bf5e61449 upstream. Since commit 71ce391dfb784 ("net: mvpp2: enable proper per-CPU TX buffers unmapping"), we are not correctly DMA unmapping TX buffers for fragments. Indeed, the mvpp2_txq_inc_put() function only stores in the txq_cpu->tx_buffs[] array the physical address of the buffer to be DMA-unmapped when skb != NULL. In addition, when DMA-unmapping, we use skb_headlen(skb) to get the size to be unmapped. Both of this works fine for TX descriptors that are associated directly to a SKB, but not the ones that are used for fragments, with a NULL pointer as skb: - We have a NULL physical address when calling DMA unmap - skb_headlen(skb) crashes because skb is NULL This causes random crashes when fragments are used. To solve this problem, we need to: - Store the physical address of the buffer to be unmapped unconditionally, regardless of whether it is tied to a SKB or not. - Store the length of the buffer to be unmapped, which requires a new field. Instead of adding a third array to store the length of the buffer to be unmapped, and as suggested by David Miller, this commit refactors the tx_buffs[] and tx_skb[] arrays of 'struct mvpp2_txq_pcpu' into a separate structure 'mvpp2_txq_pcpu_buf', to which a 'size' field is added. Therefore, instead of having three arrays to allocate/free, we have a single one, which also improve data locality, reducing the impact on the CPU cache. Fixes: 71ce391dfb784 ("net: mvpp2: enable proper per-CPU TX buffers unmapping") Reported-by: Raphael G <raphael.glon@corp.ovh.com> Cc: Raphael G <raphael.glon@corp.ovh.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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