From: Ludovic Barre ludovic.barre@st.com
commit fe8d33bd33d527dee3155d2bccd714a655f37334 upstream.
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 [<c03138c0>] (unwind_backtrace) from [<c030d760>] (show_stack+0x10/0x14) [<c030d760>] (show_stack) from [<c0f2eb28>] (dump_stack+0xc0/0xd4) [<c0f2eb28>] (dump_stack) from [<c034a14c>] (__warn+0xd0/0xf8) [<c034a14c>] (__warn) from [<c034a530>] (warn_slowpath_fmt+0x94/0xb8) [<c034a530>] (warn_slowpath_fmt) from [<c03bca0c>] (add_dma_entry+0x16c/0x17c) [<c03bca0c>] (add_dma_entry) from [<c03bdf54>] (debug_dma_map_sg+0xe4/0x3d4) [<c03bdf54>] (debug_dma_map_sg) from [<c0d09244>] (sdmmc_idma_prep_data+0x94/0xf8) [<c0d09244>] (sdmmc_idma_prep_data) from [<c0d05a2c>] (mmci_prep_data+0x2c/0xb0) [<c0d05a2c>] (mmci_prep_data) from [<c0d073ec>] (mmci_start_data+0x134/0x2f0) [<c0d073ec>] (mmci_start_data) from [<c0d078d0>] (mmci_request+0xe8/0x154) [<c0d078d0>] (mmci_request) from [<c0cecb44>] (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 ludovic.barre@st.com 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 ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/mmc/host/mmci_stm32_sdmmc.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c +++ b/drivers/mmc/host/mmci_stm32_sdmmc.c @@ -162,6 +162,9 @@ static int sdmmc_idma_start(struct mmci_ 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)