From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings , David Miller Subject: [ 16/17] sfc: Fix efx_rx_buf_offset() for recycled pages Date: Sun, 29 Sep 2013 12:26:55 -0700 Message-Id: <20130929190758.245268941@linuxfoundation.org> In-Reply-To: <20130929190757.138351117@linuxfoundation.org> References: <20130929190757.138351117@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings 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 Cc: David Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/sfc/rx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/sfc/rx.c +++ b/drivers/net/sfc/rx.c @@ -311,8 +311,9 @@ static void efx_resurrect_rx_buffer(stru 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;