>From 55961f9a914e637f143da275da42154a49c9743a Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Fri, 6 Sep 2013 22:39:20 +0100 Subject: sfc: Fix efx_rx_buf_offset() for recycled pages 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 --- 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 7b3c068..62311ad3 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -311,8 +311,9 @@ 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->flags = EFX_RX_BUF_PAGE; ++rx_queue->added_count; -- 1.8.1.4