lkml.org 
[lkml]   [2020]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.7 152/163] mmc: mmci_sdmmc: fix DMA API warning overlapping mappings
    Date
    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
    @@ -188,6 +188,9 @@ 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)

    \
     
     \ /
      Last update: 2022-09-17 16:07    [W:3.275 / U:0.116 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site