dmaengine: intel_mid_dma: locking and freeing fixes

Two issues are fixed:

1. DMA descriptors are reused so when freeing lli structures
that are linked to them, the pointer must be nulled.

2. midc_scan_descriptors() must be called with the
channel lock held.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/dma/intel_mid_dma.c b/drivers/dma/intel_mid_dma.c
index 01929ed6659d..d4b961677e02 100644
--- a/drivers/dma/intel_mid_dma.c
+++ b/drivers/dma/intel_mid_dma.c
@@ -280,7 +280,8 @@ static void midc_dostart(struct intel_mid_dma_chan *midc,
  * callbacks but must be called with the lock held.
  */
 static void midc_descriptor_complete(struct intel_mid_dma_chan *midc,
-               struct intel_mid_dma_desc *desc)
+                struct intel_mid_dma_desc *desc)
+                __releases(&midc->lock) __acquires(&midc->lock)
 {
         struct dma_async_tx_descriptor  *txd = &desc->txd;
         dma_async_tx_callback callback_txd = NULL;
@@ -311,6 +312,7 @@ static void midc_descriptor_complete(struct intel_mid_dma_chan *midc,
                         pci_pool_free(desc->lli_pool, desc->lli,
                                                 desc->lli_phys);
                         pci_pool_destroy(desc->lli_pool);
+                        desc->lli = NULL;
                 }
                 list_move(&desc->desc_node, &midc->free_list);
                 midc->busy = false;
@@ -490,7 +492,9 @@ static enum dma_status intel_mid_dma_tx_status(struct dma_chan *chan,
 
         ret = dma_async_is_complete(cookie, last_complete, last_used);
         if (ret != DMA_SUCCESS) {
+                spin_lock_bh(&midc->lock);
                 midc_scan_descriptors(to_middma_device(chan->device), midc);
+                spin_unlock_bh(&midc->lock);
 
                 last_complete = midc->completed;
                 last_used = chan->cookie;
@@ -566,6 +570,7 @@ static int intel_mid_dma_device_control(struct dma_chan *chan,
                         pci_pool_free(desc->lli_pool, desc->lli,
                                                 desc->lli_phys);
                         pci_pool_destroy(desc->lli_pool);
+                        desc->lli = NULL;
                 }
                 list_move(&desc->desc_node, &midc->free_list);
         }