From fe8d33bd33d527dee3155d2bccd714a655f37334 Mon Sep 17 00:00:00 2001 From: Ludovic Barre Date: Tue, 26 May 2020 17:51:02 +0200 Subject: [PATCH] mmc: mmci_sdmmc: fix DMA API warning overlapping mappings Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning: WARNING: CPU: 1 PID: 20 at kernel/dma/debug.c:500 add_dma_entry+0x16c/0x17c DMA-API: exceeded 7 overlapping mappings of cacheline 0x031d2645 Modules linked in: CPU: 1 PID: 20 Comm: kworker/1:1 Not tainted 5.5.0-rc2-00021-gdeda30999c2b-dirty #49 Hardware name: STM32 (Device Tree Support) Workqueue: events_freezable mmc_rescan [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xc0/0xd4) [] (dump_stack) from [] (__warn+0xd0/0xf8) [] (__warn) from [] (warn_slowpath_fmt+0x94/0xb8) [] (warn_slowpath_fmt) from [] (add_dma_entry+0x16c/0x17c) [] (add_dma_entry) from [] (debug_dma_map_sg+0xe4/0x3d4) [] (debug_dma_map_sg) from [] (sdmmc_idma_prep_data+0x94/0xf8) [] (sdmmc_idma_prep_data) from [] (mmci_prep_data+0x2c/0xb0) [] (mmci_prep_data) from [] (mmci_start_data+0x134/0x2f0) [] (mmci_start_data) from [] (mmci_request+0xe8/0x154) [] (mmci_request) from [] (mmc_start_request+0x94/0xbc) DMA api debug brings to light leaking dma-mappings, dma_map_sg and dma_unmap_sg are not correctly balanced. If a request is prepared, the dma_map/unmap are done in asynchronous call pre_req (prep_data) and post_req (unprep_data). In this case the dma-mapping is right balanced. But if the request was not prepared, the data->host_cookie is define to zero and the dma_map/unmap must be done in the request. The dma_map is called by mmci_dma_start (prep_data), but there is no dma_unmap in this case. This patch adds dma_unmap_sg when the dma is finalized and the data cookie is zero (request not prepared). Signed-off-by: Ludovic Barre Link: https://lore.kernel.org/r/20200526155103.12514-2-ludovic.barre@st.com Fixes: 46b723dd867d ("mmc: mmci: add stm32 sdmmc variant") Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson --- drivers/mmc/host/mmci_stm32_sdmmc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c index 14f99d8aa3f08f..2965b1c062e19e 100644 --- a/drivers/mmc/host/mmci_stm32_sdmmc.c +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c @@ -188,6 +188,9 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl) static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data) { writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR); + + if (!data->host_cookie) + sdmmc_idma_unprep_data(host, data, 0); } static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired)