On 10/29/2015 10:59 PM, Andy Shevchenko wrote: > On Tue, Oct 20, 2015 at 12:46 PM, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: >> The DMAengine API has a long standing race condition that is inherent to >> the API itself. Calling dmaengine_terminate_all() is supposed to stop and >> abort any pending or active transfers that have previously been submitted. >> Unfortunately it is possible that this operation races against a currently >> running (or with some drivers also scheduled) completion callback. > > [] > >> +/** >> + * dmaengine_terminate_sync() - Terminate all active DMA transfers >> + * @chan: The channel for which to terminate the transfers >> + * >> + * Calling this function will terminate all active and pending transfers >> + * that have previously been submitted to the channel. It is similar to >> + * dmaengine_terminate_async() but guarantees that the DMA transfer has actually >> + * stopped and that all complete callbacks have finished running when the >> + * function returns. >> + * >> + * This function must only be called from non-atomic context and must not be >> + * called from within a complete callback of a descriptor submitted on the same >> + * channel. >> + */ >> +static inline int dmaengine_terminate_sync(struct dma_chan *chan) >> +{ >> + int ret; > > Might be a good idea to add might_sleep(); here. Sound like a good idea, thanks, I'll add it (in dmaengine_synchronize() though). > >> + >> + ret = dmaengine_terminate_async(chan); >> + if (ret) >> + return ret; >> + >> + dmaengine_synchronize(chan); >> + >> + return 0; >> +} > > -- 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