The DMAengine API has a long standing issue that is inherent to the API itself. For a client that calls dmaengine_terminate_all() it is not possible to properly synchronize the completion of any currently running complete callbacks to the current context. This means it is possible to end up with a use-after-free race condition if client frees resources that are accessed in a complete callback before the complete callback has finished running. This patch series introduces a new explicit synchronization primitive to the DMAengine API which allows clients to ensure that all complete callbacks have finished running. This allows them to safely free any resources that might be accessed in a complete callback. The series for now only implements synchronization support for a single driver and only updates single client to make use of the new API. If there is agreement on the general approach more will follow. - Lars Lars-Peter Clausen (4): dmaengine: Add transfer termination synchronization support dmaengine: virt-dma: Add synchronization helper function dmaengine: axi_dmac: Add synchronization support ALSA: pcm_dmaengine: Properly synchronize DMA on shutdown Documentation/dmaengine/client.txt | 38 ++++++++++++++- Documentation/dmaengine/provider.txt | 20 +++++++- drivers/dma/dma-axi-dmac.c | 8 ++++ drivers/dma/dmaengine.c | 5 +- drivers/dma/virt-dma.h | 13 ++++++ include/linux/dmaengine.h | 90 ++++++++++++++++++++++++++++++++++++ sound/core/pcm_dmaengine.c | 9 ++-- 7 files changed, 175 insertions(+), 8 deletions(-) -- 2.1.4 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
