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Subject[PATCH v2] dma-debug: enhance dma_debug_device_change() to check for mapping errors
Date
dma-debug checks to verify if driver validated the address returned by
dma mapping routines when driver does unmap. If a driver doesn't call
unmap, failure to check mapping errors isn't detected and reported.

Enhancing existing bus notifier_call dma_debug_device_change() to check
for mapping errors at the same time it detects leaked dma buffers for
BUS_NOTIFY_UNBOUND_DRIVER event. It scans for mapping errors and if any
found, prints one warning message that includes mapping error count.

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
---
lib/dma-debug.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index d87a17a..e34865e 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -717,6 +717,7 @@ static int device_dma_allocations(struct device *dev, struct dma_debug_entry **o
struct dma_debug_entry *entry;
unsigned long flags;
int count = 0, i;
+ int map_err_cnt = 0;

local_irq_save(flags);

@@ -724,6 +725,8 @@ static int device_dma_allocations(struct device *dev, struct dma_debug_entry **o
spin_lock(&dma_entry_hash[i].lock);
list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
if (entry->dev == dev) {
+ if (entry->map_err_type == MAP_ERR_NOT_CHECKED)
+ map_err_cnt += 1;
count += 1;
*out_entry = entry;
}
@@ -733,6 +736,10 @@ static int device_dma_allocations(struct device *dev, struct dma_debug_entry **o

local_irq_restore(flags);

+ if (map_err_cnt)
+ dev_warn(entry->dev,
+ "DMA-API: device driver failed to check map errors: "
+ "[count] = %d\n", map_err_cnt);
return count;
}

--
1.8.3.2


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