linux-kernel - [PATCH] dma-debug: remove broken dma memory leak detection for 2.6.30

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Message-ID: <1240576557-22442-1-git-send-email-joerg.roedel@amd.com>
Date:	Fri, 24 Apr 2009 14:35:57 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	Ingo Molnar <mingo@...hat.com>
CC:	linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
	Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH] dma-debug: remove broken dma memory leak detection for 2.6.30

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.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 lib/dma-debug.c |   53 +----------------------------------------------------
 1 files changed, 1 insertions(+), 52 deletions(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index d3da7ed..69da09a 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -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 */
 }
 
 /*
-- 
1.6.2.3


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