lkml.org 
[lkml]   [2020]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v8 02/19] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list
Date
The interrupt handler puts a half-completed DMA descriptor on a free list
and then schedules tasklet to process bottom half of the descriptor that
executes client's callback, this creates possibility to pick up the busy
descriptor from the free list. Thus, let's disallow descriptor's re-use
until it is fully processed.

Cc: <stable@vger.kernel.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/dma/tegra20-apb-dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 319f31d27014..4a750e29bfb5 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -281,7 +281,7 @@ static struct tegra_dma_desc *tegra_dma_desc_get(

/* Do not allocate if desc are waiting for ack */
list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
- if (async_tx_test_ack(&dma_desc->txd)) {
+ if (async_tx_test_ack(&dma_desc->txd) && !dma_desc->cb_count) {
list_del(&dma_desc->node);
spin_unlock_irqrestore(&tdc->lock, flags);
dma_desc->txd.flags = 0;
--
2.24.0
\
 
 \ /
  Last update: 2020-02-09 17:43    [W:0.161 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site