The content of pl330_thread could be modified in pl330_update
without protection by the lock from the dma channel who currently
holding this thread. This could cause bug to the calculation of
in pl330_tx_status, if the running request has just been done and
moving to next request while calculating the residual number, an
invalid number from BUSY descriptor could be added up.
---
drivers/dma/pl330.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 31e9c49..2449cb7 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1564,6 +1564,19 @@ static void pl330_dotask(unsigned long data)
return;
}
+static struct dma_pl330_chan *get_dma_channel(struct pl330_dmac *pl330,
+ struct pl330_thread *thrd)
+{
+ struct dma_pl330_chan *pch;
+ int i;
+ for (i = 0; i < pl330->num_peripherals; i++) {
+ pch = &pl330->peripherals[i];
+ if (pch && pch->thread == thrd)
+ return pch;
+ }
+ return NULL;
+}
+
/* Returns 1 if state was updated, 0 otherwise */
static int pl330_update(struct pl330_dmac *pl330)
{
@@ -1613,6 +1626,7 @@ static int pl330_update(struct pl330_dmac *pl330)
for (ev = 0; ev < pl330->pcfg.num_events; ev++) {
if (val & (1 << ev)) { /* Event occurred */
struct pl330_thread *thrd;
+ struct dma_pl330_chan *pch;
u32 inten = readl(regs + INTEN);
int active;
@@ -1625,6 +1639,9 @@ static int pl330_update(struct pl330_dmac *pl330)
id = pl330->events[ev];
thrd = &pl330->channels[id];
+ pch = get_dma_channel(pl330, thrd);
+ if (pch)
+ spin_lock_irqsave(&pch->lock, flags);
active = thrd->req_running;
if (active == -1) /* Aborted */
@@ -1638,6 +1655,8 @@ static int pl330_update(struct pl330_dmac *pl330)
/* Get going again ASAP */
_start(thrd);
+ if (pch)
+ spin_unlock_irqrestore(&pch->lock, flags);
/* For now, just make a list of callbacks to be done */
list_add_tail(&descdone->rqd, &pl330->req_done);
--
2.6.6
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