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dma-debug: add a check dma memory leaks 

Impact: allow architectures to monitor busses for dma mem leakage

This patch adds checking code to detect if a device has pending DMA
operations when it is about to be unbound from its device driver.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2009-03-16 17:32:14 +01:00
parent 2e34bde185
commit 41531c8f5f
2 changed files with 62 additions and 0 deletions
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7
include/linux/dma-debug.h
View File

@ -24,9 +24,12 @@
struct device;
struct scatterlist;
struct bus_type;
#ifdef CONFIG_DMA_API_DEBUG
extern void dma_debug_add_bus(struct bus_type *bus);
extern void dma_debug_init(u32 num_entries);
extern void debug_dma_map_page(struct device *dev, struct page *page,
@ -80,6 +83,10 @@ extern void debug_dma_dump_mappings(struct device *dev);
#else /* CONFIG_DMA_API_DEBUG */
void dma_debug_add_bus(struct bus_type *bus)
{
}
static inline void dma_debug_init(u32 num_entries)
{
}

55
lib/dma-debug.c
View File

@ -400,6 +400,61 @@ out_err:
return -ENOMEM;
}
static int device_dma_allocations(struct device *dev)
{
struct dma_debug_entry *entry;
unsigned long flags;
int count = 0, i;
for (i = 0; i < HASH_SIZE; ++i) {
spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
if (entry->dev == dev)
count += 1;
}
spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
}
return count;
}
static int dma_debug_device_change(struct notifier_block *nb,
unsigned long action, void *data)
{
struct device *dev = data;
int count;
switch (action) {
case BUS_NOTIFY_UNBIND_DRIVER:
count = device_dma_allocations(dev);
if (count == 0)
break;
err_printk(dev, NULL, "DMA-API: device driver has pending "
"DMA allocations while released from device "
"[count=%d]\n", count);
break;
default:
break;
}
return 0;
}
void dma_debug_add_bus(struct bus_type *bus)
{
struct notifier_block *nb;
nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
if (nb == NULL) {
printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
return;
}
nb->notifier_call = dma_debug_device_change;
bus_register_notifier(bus, nb);
}
/*
* Let the architectures decide how many entries should be preallocated.