[PATCH v2 2/4] iop-adma: fix lockdep false positive
Dan Williams
dan.j.williams at intel.com
Mon Aug 31 11:40:47 EDT 2009
lockdep correctly identifies a potential recursive locking case for
iop_chan->lock, but in the dependency submission case we expect that the same
class will be acquired for both the parent dependency and the child channel.
Signed-off-by: Dan Williams <dan.j.williams at intel.com>
---
drivers/dma/iop-adma.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
index ce45f3f..9c752bd 100644
--- a/drivers/dma/iop-adma.c
+++ b/drivers/dma/iop-adma.c
@@ -288,7 +288,12 @@ static void iop_adma_tasklet(unsigned long data)
{
struct iop_adma_chan *iop_chan = (struct iop_adma_chan *) data;
- spin_lock(&iop_chan->lock);
+ /* lockdep will flag depedency submissions as potentially
+ * recursive locking, this is not the case as a dependency
+ * submission will never recurse a channels submit routine.
+ * There are checks in async_tx.c to prevent this.
+ */
+ spin_lock_nested(&iop_chan->lock, SINGLE_DEPTH_NESTING);
__iop_adma_slot_cleanup(iop_chan);
spin_unlock(&iop_chan->lock);
}
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