dma-debug: remove broken dma memory leak detection for 2.6.30 (314eeac9) · Commits · 戴 / test

The feature needs some more work because the notfier which is used to check for pending allocations is called before the device drivers ->remove() function. Therefore this feature reports false positives. A real fix for this issue is to introduce a new notifier event which sent _after_ the driver has deinitialized itself. That will done for the next kernel version. [ Impact: reduce the scope of CONFIG_DMA_API_DEBUG=y checks ] Signed-off-by:

Joerg Roedel <joerg.roedel@amd.com> Cc: iommu@lists.linux-foundation.org LKML-Reference: <1240576557-22442-1-git-send-email-joerg.roedel@amd.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

lib/dma-debug.c

+1 −52

Original line number	Diff line number	Diff line
		@@ -400,60 +400,9 @@ 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);
		/* FIXME: register notifier */
		}

		/*

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