On Thu, Aug 20, 2015 at 04:00:56PM +0530, Rameshwar Prasad Sahu wrote:
> This patch fixes the an locking issue where client callback performs
^^^^^^^^^^^^
??
> further submission.
Do you men you are preventing that or fixing for this to be allowed?
>
> Signed-off-by: Rameshwar Prasad Sahu <rsahu@xxxxxxx>
> ---
> drivers/dma/xgene-dma.c | 33 ++++++++++++++++++++++-----------
> 1 file changed, 22 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
> index d1c8809..0b82bc0 100644
> --- a/drivers/dma/xgene-dma.c
> +++ b/drivers/dma/xgene-dma.c
> @@ -763,12 +763,17 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
> struct xgene_dma_ring *ring = &chan->rx_ring;
> struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
> struct xgene_dma_desc_hw *desc_hw;
> + struct list_head ld_completed;
> u8 status;
>
> + INIT_LIST_HEAD(&ld_completed);
> +
> + spin_lock_bh(&chan->lock);
> +
> /* Clean already completed and acked descriptors */
> xgene_dma_clean_completed_descriptor(chan);
>
> - /* Run the callback for each descriptor, in order */
> + /* Move all completed descriptors to ld completed queue, in order */
> list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_running, node) {
> /* Get subsequent hw descriptor from DMA rx ring */
> desc_hw = &ring->desc_hw[ring->head];
> @@ -811,15 +816,17 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
> /* Mark this hw descriptor as processed */
> desc_hw->m0 = cpu_to_le64(XGENE_DMA_DESC_EMPTY_SIGNATURE);
>
> - xgene_dma_run_tx_complete_actions(chan, desc_sw);
> -
> - xgene_dma_clean_running_descriptor(chan, desc_sw);
> -
> /*
> * Decrement the pending transaction count
> * as we have processed one
> */
> chan->pending--;
> +
> + /*
> + * Delete this node from ld running queue and append it to
> + * ld completed queue for further processing
> + */
> + list_move_tail(&desc_sw->node, &ld_completed);
> }
>
> /*
> @@ -828,6 +835,14 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
> * ahead and free the descriptors below.
> */
> xgene_chan_xfer_ld_pending(chan);
> +
> + spin_unlock_bh(&chan->lock);
> +
> + /* Run the callback for each descriptor, in order */
> + list_for_each_entry_safe(desc_sw, _desc_sw, &ld_completed, node) {
> + xgene_dma_run_tx_complete_actions(chan, desc_sw);
> + xgene_dma_clean_running_descriptor(chan, desc_sw);
> + }
> }
>
> static int xgene_dma_alloc_chan_resources(struct dma_chan *dchan)
> @@ -876,11 +891,11 @@ static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
> if (!chan->desc_pool)
> return;
>
> - spin_lock_bh(&chan->lock);
> -
> /* Process all running descriptor */
> xgene_dma_cleanup_descriptors(chan);
>
> + spin_lock_bh(&chan->lock);
> +
> /* Clean all link descriptor queues */
> xgene_dma_free_desc_list(chan, &chan->ld_pending);
> xgene_dma_free_desc_list(chan, &chan->ld_running);
> @@ -1200,15 +1215,11 @@ static void xgene_dma_tasklet_cb(unsigned long data)
> {
> struct xgene_dma_chan *chan = (struct xgene_dma_chan *)data;
>
> - spin_lock_bh(&chan->lock);
> -
> /* Run all cleanup for descriptors which have been completed */
> xgene_dma_cleanup_descriptors(chan);
>
> /* Re-enable DMA channel IRQ */
> enable_irq(chan->rx_irq);
> -
> - spin_unlock_bh(&chan->lock);
> }
>
> static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id)
> --
> 1.8.2.1
>
--
~Vinod
--
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