[PATCH v2] dmaengine: xgene-dma: Fix the lock to allow client for further submission of requests

Rameshwar Prasad Sahu
2015-08-21T09:04:21Z

This patch provides the fix in the cleanup routing such that client can perform
further submission by releasing the lock before calling client's callback function.

Signed-off-by: Rameshwar Prasad Sahu <rsahu@apm.com>
---
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