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    Subject[PATCH AUTOSEL 5.4 141/330] dmaengine: tegra-apb: Prevent race conditions on channel's freeing
    Date
    From: Dmitry Osipenko <digetx@gmail.com>

    [ Upstream commit 8e84172e372bdca20c305d92d51d33640d2da431 ]

    It's incorrect to check the channel's "busy" state without taking a lock.
    That shouldn't cause any real troubles, nevertheless it's always better
    not to have any race conditions in the code.

    Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
    Acked-by: Jon Hunter <jonathanh@nvidia.com>
    Link: https://lore.kernel.org/r/20200209163356.6439-5-digetx@gmail.com
    Signed-off-by: Vinod Koul <vkoul@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/dma/tegra20-apb-dma.c | 3 +--
    1 file changed, 1 insertion(+), 2 deletions(-)

    diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
    index 4a750e29bfb53..3fe27dbde5b2b 100644
    --- a/drivers/dma/tegra20-apb-dma.c
    +++ b/drivers/dma/tegra20-apb-dma.c
    @@ -1287,8 +1287,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)

    dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);

    - if (tdc->busy)
    - tegra_dma_terminate_all(dc);
    + tegra_dma_terminate_all(dc);

    spin_lock_irqsave(&tdc->lock, flags);
    list_splice_init(&tdc->pending_sg_req, &sg_req_list);
    --
    2.25.1
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