On Tue, Feb 24, 2015 at 03:00:03PM +0200, Stanimir Varbanov wrote:
> +static void spi_qup_dma_done(void *data)
> +{
> + struct spi_qup *qup = data;
> +
> + if (atomic_dec_and_test(&qup->dma_outstanding))
> + complete(&qup->done);
> +}I'm finding it hard to be thrilled about the use of atomics for synchronization (they're just generally hard to work with) and... > + cookie = dmaengine_submit(desc); > + ret = dma_submit_error(cookie); > + if (ret) > + return ret; > + atomic_inc(&qup->dma_outstanding); ..don't we have two potential races here: one if somehow the DMA manages to complete prior to the atomic_inc() (unlikely but that's what race conditions are all about really) and one if we are issuing multiple DMAs and the early ones complete before the later ones are issued?
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