Commit-ID: 41531c8f5f05aba5ec645d9770557eedbf75b422
Gitweb: http://git.kernel.org/tip/41531c8f5f05aba5ec645d9770557eedbf75b422
Author: Joerg Roedel <joerg.roedel@xxxxxxx>
AuthorDate: Mon, 16 Mar 2009 17:32:14 +0100
Commit: Joerg Roedel <joerg.roedel@xxxxxxx>
CommitDate: Tue, 17 Mar 2009 12:56:49 +0100
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@xxxxxxx>
---
include/linux/dma-debug.h | 7 +++++
lib/dma-debug.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 62 insertions(+), 0 deletions(-)
diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h
index 46a11c1..e851d23 100644
--- a/include/linux/dma-debug.h
+++ b/include/linux/dma-debug.h
@@ -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)
{
}
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 6022eb4..9a350b4 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -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.
--
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