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, Maxime Chevallier , Mark Brown Subject: [PATCH 4.9 15/95] spi: Fix scatterlist elements size in spi_map_buf Date: Sun, 22 Apr 2018 15:52:44 +0200 Message-Id: <20180422135211.060960284@linuxfoundation.org> In-Reply-To: <20180422135210.432103639@linuxfoundation.org> References: <20180422135210.432103639@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime Chevallier commit ce99319a182fe766be67f96338386f3ec73e321c upstream. When SPI transfers can be offloaded using DMA, the SPI core need to build a scatterlist to make sure that the buffer to be transferred is dma-able. This patch fixes the scatterlist entry size computation in the case where the maximum acceptable scatterlist entry supported by the DMA controller is less than PAGE_SIZE, when the buffer is vmalloced. For each entry, the actual size is given by the minimum between the desc_len (which is the max buffer size supported by the DMA controller) and the remaining buffer length until we cross a page boundary. Fixes: 65598c13fd66 ("spi: Fix per-page mapping of unaligned vmalloc-ed buffer") Signed-off-by: Maxime Chevallier Signed-off-by: Mark Brown Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -743,8 +743,14 @@ static int spi_map_buf(struct spi_master for (i = 0; i < sgs; i++) { if (vmalloced_buf || kmap_buf) { - min = min_t(size_t, - len, desc_len - offset_in_page(buf)); + /* + * Next scatterlist entry size is the minimum between + * the desc_len and the remaining buffer length that + * fits in a page. + */ + min = min_t(size_t, desc_len, + min_t(size_t, len, + PAGE_SIZE - offset_in_page(buf))); if (vmalloced_buf) vm_page = vmalloc_to_page(buf); else