Subject: [merged] dma-debug-fix-overlap-detection.patch removed from -mm tree
To: dan.j.williams@xxxxxxxxx,linux@xxxxxxxxxxxxxx,romieu@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 30 Jan 2014 12:05:24 -0800
The patch titled
Subject: dma-debug: fix overlap detection
has been removed from the -mm tree. Its filename was
dma-debug-fix-overlap-detection.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: dma-debug: fix overlap detection
0abdd7a81b7e ("dma-debug: introduce debug_dma_assert_idle()") was reworked
to expand the overlap counter to the full range expressable by 3 tag bits,
but it has a thinko in treating the overlap counter as a pure reference
count for the entry.
Instead of deleting when the reference-count drops to zero, we need to
delete when the overlap-count drops below zero. Also, when detecting
overflow we can just test the overlap-count > MAX rather than applying
special meaning to 0.
Regression report available here:
http://marc.info/?l=linux-netdev&m=139073373932386&w=2
This patch, now tested on the original net_dma case, sees the expected
handful of reports before the eventual data corruption occurs.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Cc: Francois Romieu <romieu@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/dma-debug.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff -puN lib/dma-debug.c~dma-debug-fix-overlap-detection lib/dma-debug.c
--- a/lib/dma-debug.c~dma-debug-fix-overlap-detection
+++ a/lib/dma-debug.c
@@ -463,7 +463,7 @@ static int active_pfn_set_overlap(unsign
int i;
if (overlap > ACTIVE_PFN_MAX_OVERLAP || overlap < 0)
- return 0;
+ return overlap;
for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
if (overlap & 1 << i)
@@ -486,7 +486,7 @@ static void active_pfn_inc_overlap(unsig
* debug_dma_assert_idle() as the pfn may be marked idle
* prematurely.
*/
- WARN_ONCE(overlap == 0,
+ WARN_ONCE(overlap > ACTIVE_PFN_MAX_OVERLAP,
"DMA-API: exceeded %d overlapping mappings of pfn %lx\n",
ACTIVE_PFN_MAX_OVERLAP, pfn);
}
@@ -517,7 +517,11 @@ static void active_pfn_remove(struct dma
unsigned long flags;
spin_lock_irqsave(&radix_lock, flags);
- if (active_pfn_dec_overlap(entry->pfn) == 0)
+ /* since we are counting overlaps the final put of the
+ * entry->pfn will occur when the overlap count is 0.
+ * active_pfn_dec_overlap() returns -1 in that case
+ */
+ if (active_pfn_dec_overlap(entry->pfn) < 0)
radix_tree_delete(&dma_active_pfn, entry->pfn);
spin_unlock_irqrestore(&radix_lock, flags);
}
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
origin.patch
linux-next.patch
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