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Subject[PATCH 1/3] dmaengine: intel_mid_dma: locking and freeing fixes
Date
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>
---
drivers/dma/intel_mid_dma.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/intel_mid_dma.c b/drivers/dma/intel_mid_dma.c
index 01929ed..d4b9616 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);
}
--
1.7.6.4


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