Messages in this thread | | | Date | Sun, 21 Nov 2021 20:08:34 +0000 | From | Paul Cercueil <> | Subject | Re: [PATCH 01/15] iio: buffer-dma: Get rid of incoming/outgoing queues |
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Le dim., nov. 21 2021 at 19:49:03 +0100, Lars-Peter Clausen <lars@metafoo.de> a écrit : > On 11/21/21 6:52 PM, Paul Cercueil wrote: >> Hi Lars, >> >> Le dim., nov. 21 2021 at 17:23:35 +0100, Lars-Peter Clausen >> <lars@metafoo.de> a écrit : >>> On 11/15/21 3:19 PM, Paul Cercueil wrote: >>>> The buffer-dma code was using two queues, incoming and outgoing, to >>>> manage the state of the blocks in use. >>>> >>>> While this totally works, it adds some complexity to the code, >>>> especially since the code only manages 2 blocks. It is much easier >>>> to >>>> just check each block's state manually, and keep a counter for the >>>> next >>>> block to dequeue. >>>> >>>> Since the new DMABUF based API wouldn't use these incoming and >>>> outgoing >>>> queues anyway, getting rid of them now makes the upcoming changes >>>> simpler. >>>> >>>> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >>> The outgoing queue is going to be replaced by fences, but I think >>> we need to keep the incoming queue. >> >> Blocks are always accessed in sequential order, so we now have a >> "queue->next_dequeue" that cycles between the buffers allocated for >> fileio. >> >>>> [...] >>>> @@ -442,28 +435,33 @@ EXPORT_SYMBOL_GPL(iio_dma_buffer_disable); >>>> static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue >>>> *queue, >>>> struct iio_dma_buffer_block *block) >>>> { >>>> - if (block->state == IIO_BLOCK_STATE_DEAD) { >>>> + if (block->state == IIO_BLOCK_STATE_DEAD) >>>> iio_buffer_block_put(block); >>>> - } else if (queue->active) { >>>> + else if (queue->active) >>>> iio_dma_buffer_submit_block(queue, block); >>>> - } else { >>>> + else >>>> block->state = IIO_BLOCK_STATE_QUEUED; >>>> - list_add_tail(&block->head, &queue->incoming); >>> If iio_dma_buffer_enqueue() is called with a dmabuf and the buffer >>> is not active, it will be marked as queued, but we don't actually >>> keep a reference to it anywhere. It will never be submitted to >>> the DMA, and it will never be signaled as completed. >> >> We do keep a reference to the buffers, in the queue->fileio.blocks >> array. When the buffer is enabled, all the blocks in that array >> that are in the "queued" state will be submitted to the DMA. >> > But not when used in combination with the DMA buf changes later in > this series. >
That's still the case after the DMABUF changes of the series. Or can you point me exactly what you think is broken?
-Paul
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