| From | Ben Hutchings <> | Date | Mon, 21 Oct 2013 09:46:28 +0100 | Subject | [PATCH 3.2 130/149] sfc: Fix efx_rx_buf_offset() for recycled pages |
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3.2.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Ben Hutchings <bhutchings@solarflare.com>
This bug fix is only for stable branches older than 3.10. The bug was fixed upstream by commit 2768935a4660 ('sfc: reuse pages to avoid DMA mapping/unmapping costs'), but that change is totally unsuitable for stable.
Commit b590ace09d51 ('sfc: Fix efx_rx_buf_offset() in the presence of swiotlb') added an explicit page_offset member to struct efx_rx_buffer, which must be set consistently with the u.page and dma_addr fields. However, it failed to add the necessary assignment in efx_resurrect_rx_buffer(). It also did not correct the calculation of efx_rx_buffer::dma_addr in efx_resurrect_rx_buffer(), which assumes that DMA-mapping a page will result in a page-aligned DMA address (exactly what swiotlb violates).
Add the assignment of efx_rx_buffer::page_offset and change the calculation of dma_addr to make use of it.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> --- drivers/net/ethernet/sfc/rx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c index 9ce8665..c231b3f 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -312,8 +312,9 @@ static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue, index = rx_queue->added_count & rx_queue->ptr_mask; new_buf = efx_rx_buffer(rx_queue, index); - new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1); new_buf->u.page = rx_buf->u.page; + new_buf->page_offset = rx_buf->page_offset ^ (PAGE_SIZE >> 1); + new_buf->dma_addr = state->dma_addr + new_buf->page_offset; new_buf->len = rx_buf->len; new_buf->is_page = true; ++rx_queue->added_count; -- 1.8.1.4
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