On Wed, Oct 04, 2017 at 02:37:23PM +0300, Alexander Kochetkov wrote: > If two concurrent threads call pl330_get_desc() when DMAC descriptor > pool is empty it is possible that allocation for one of threads will fail > with message: > > kernel: dma-pl330 20078000.dma-controller: pl330_get_desc:2469 ALERT! > > Here how that can happen. Thread A calls pl330_get_desc() to get > descriptor. If DMAC descriptor pool is empty pl330_get_desc() allocates > new descriptor on shared pool using add_desc() and then get newly > allocated descriptor using pluck_desc(). At the same time thread B calls > pluck_desc() and take newly allocated descriptor. In that case descriptor > allocation for thread A will fail. > > Using on-stack pool for new descriptor allow avoid the issue described. > The patch modify pl330_get_desc() to use on-stack pool for allocation > new descriptors.
Applied, thanks -- ~Vinod
