From 41531c8f5f05aba5ec645d9770557eedbf75b422 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 16 Mar 2009 17:32:14 +0100 Subject: [PATCH] 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 --- include/linux/dma-debug.h | 7 +++++ lib/dma-debug.c | 55 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+) diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h index 46a11c10da04..e851d23e91eb 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 6022eb4a0cd0..9a350b414a50 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. -- 2.20.1