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>

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>
Joerg Roedel
1 parent 2e34bde185
Showing 2 changed files with 62 additions and 0 deletions Side-by-side Diff
include/linux/dma-debug.h
lib/dma-debug.c
@@ -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,
@@ -79,6 +82,10 @@
 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)
 {
@@ -400,6 +400,61 @@
 	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.
...	...	@@ -24,9 +24,12 @@
24	24
25	25	struct device;
26	26	struct scatterlist;
	27	+struct bus_type;
27	28
28	29	#ifdef CONFIG_DMA_API_DEBUG
29	30
	31	+extern void dma_debug_add_bus(struct bus_type *bus);
	32	+
30	33	extern void dma_debug_init(u32 num_entries);
31	34
32	35	extern void debug_dma_map_page(struct device dev, struct page page,
...	...	@@ -79,6 +82,10 @@
79	82	extern void debug_dma_dump_mappings(struct device *dev);
80	83
81	84	#else /* CONFIG_DMA_API_DEBUG */
	85	+
	86	+void dma_debug_add_bus(struct bus_type *bus)
	87	+{
	88	+}
82	89
83	90	static inline void dma_debug_init(u32 num_entries)
84	91	{
...	...	@@ -400,6 +400,61 @@
400	400	return -ENOMEM;
401	401	}
402	402
	403	+static int device_dma_allocations(struct device *dev)
	404	+{
	405	+ struct dma_debug_entry *entry;
	406	+ unsigned long flags;
	407	+ int count = 0, i;
	408	+
	409	+ for (i = 0; i < HASH_SIZE; ++i) {
	410	+ spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
	411	+ list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
	412	+ if (entry->dev == dev)
	413	+ count += 1;
	414	+ }
	415	+ spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
	416	+ }
	417	+
	418	+ return count;
	419	+}
	420	+
	421	+static int dma_debug_device_change(struct notifier_block *nb,
	422	+ unsigned long action, void *data)
	423	+{
	424	+ struct device *dev = data;
	425	+ int count;
	426	+
	427	+
	428	+ switch (action) {
	429	+ case BUS_NOTIFY_UNBIND_DRIVER:
	430	+ count = device_dma_allocations(dev);
	431	+ if (count == 0)
	432	+ break;
	433	+ err_printk(dev, NULL, "DMA-API: device driver has pending "
	434	+ "DMA allocations while released from device "
	435	+ "[count=%d]\n", count);
	436	+ break;
	437	+ default:
	438	+ break;
	439	+ }
	440	+
	441	+ return 0;
	442	+}
	443	+
	444	+void dma_debug_add_bus(struct bus_type *bus)
	445	+{
	446	+ struct notifier_block *nb;
	447	+
	448	+ nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
	449	+ if (nb == NULL) {
	450	+ printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
	451	+ return;
	452	+ }
	453	+
	454	+ nb->notifier_call = dma_debug_device_change;
	455	+
	456	+ bus_register_notifier(bus, nb);
	457	+}
403	458
404	459	/*
405	460	* Let the architectures decide how many entries should be preallocated.