On Wed, Jan 04, 2017 at 01:22:52AM -0800, Krister Johansen wrote: > On a kernel with DEBUG_LOCKS, ioat_free_chan_resources triggers an > in_interrupt() warning. With PROVE_LOCKING, it reports detecting a > SOFTIRQ-safe to SOFTIRQ-unsafe lock ordering in the same code path. > > This is because dma_generic_alloc_coherent() checks if the GFP flags > permit blocking. It allocates from different subsystems if blocking is > permitted. The free path knows how to return the memory to the correct > allocator. If GFP_KERNEL is specified then the alloc and free end up > going through cma_alloc(), which uses mutexes. > > Given that ioat_free_chan_resources() can be called in interrupt > context, ioat_alloc_chan_resources() must specify GFP_NOWAIT so that the > allocations do not block and instead use an allocator that uses > spinlocks. Applied now, after fixing the subsystem and driver tag. -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
