ioat: close potential BUG_ON race in the descriptor cleanup path
Since ioat_cleanup_preamble() and the update of the last completed
descriptor are not synchronized there is a chance that two cleanup threads
can see descriptors to clean. If the first cleans up all pending
descriptors then the second will trigger the BUG_ON.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index bff48e8..39520f2 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -293,7 +293,7 @@
}
}
ioat->tail += i;
- BUG_ON(!seen_current); /* no active descs have written a completion? */
+ BUG_ON(active && !seen_current); /* no active descs have written a completion? */
chan->last_completion = phys_complete;
if (ioat->head == ioat->tail) {
dev_dbg(to_dev(chan), "%s: cancel completion timeout\n",