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authorDan Williams <dan.j.williams@intel.com>2010-03-03 21:21:10 -0700
committerDan Williams <dan.j.williams@intel.com>2010-03-03 21:21:10 -0700
commitaa75db0080603bae27961c0502812dfd0f522bb3 (patch)
tree3e7fbb0ef4415c9f36107a81378f00bba6db9440
parent281befa5592b0c5f9a3856b5666c62ac66d3d9ee (diff)
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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>
-rw-r--r--drivers/dma/ioat/dma_v2.c2
-rw-r--r--drivers/dma/ioat/dma_v3.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index c6e4531fe52..01ed1cfd3eb 100644
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -158,7 +158,7 @@ static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
seen_current = true;
}
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) {
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index bff48e8cffc..39520f2f7da 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -293,7 +293,7 @@ static void __cleanup(struct ioat2_dma_chan *ioat, unsigned long phys_complete)
}
}
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",