Re: [PATCH v2 1/2] dmaengine: pl330: fix descriptor allocation fail

[Vinod Koul]

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