media: v4l2-mem2mem: Avoid calling .device_run in v4l2_m2m_job_finish
v4l2_m2m_job_finish() is typically called when DMA operations complete, in interrupt handlers or DMA completion callbacks. Calling .device_run from v4l2_m2m_job_finish creates a nasty re-entrancy path into the driver. Moreover, some implementation of .device_run might need to sleep, as is the case for drivers supporting the Request API, where controls are applied via v4l2_ctrl_request_setup, which takes the ctrl handler mutex. This commit adds a deferred context that calls v4l2_m2m_try_run, and gets scheduled by v4l2_m2m_job_finish(). Before this change, device_run would be called from these paths: vb2_m2m_request_queue, or v4l2_m2m_streamon, or v4l2_m2m_qbuf v4l2_m2m_try_schedule v4l2_m2m_try_run .device_run v4l2_m2m_job_finish v4l2_m2m_try_run .device_run After this change, the latter is now gone and instead: v4l2_m2m_device_run_work v4l2_m2m_try_run .device_run Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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