forked from luck/tmp_suning_uos_patched
dma-debug: add dma_debug_resize_entries() to adjust the number of dma_debug_entries
We use a static value for the number of dma_debug_entries. It can be overwritten by a kernel command line option. Some IOMMUs (e.g. GART) can't set an appropriate value by a kernel command line option because they can't know such value until they finish initializing up their hardware. This patch adds dma_debug_resize_entries() enables IOMMUs to adjust the number of dma_debug_entries anytime. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Joerg Roedel <joerg.roedel@amd.com> Cc: fujita.tomonori@lab.ntt.co.jp Cc: akpm@linux-foundation.org LKML-Reference: <20090415182234R.fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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7e05575c42
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@ -32,6 +32,8 @@ extern void dma_debug_add_bus(struct bus_type *bus);
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extern void dma_debug_init(u32 num_entries);
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extern int dma_debug_resize_entries(u32 num_entries);
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extern void debug_dma_map_page(struct device *dev, struct page *page,
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size_t offset, size_t size,
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int direction, dma_addr_t dma_addr,
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@ -91,6 +93,11 @@ static inline void dma_debug_init(u32 num_entries)
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{
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}
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static inline int dma_debug_resize_entries(u32 num_entries)
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{
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return 0;
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}
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static inline void debug_dma_map_page(struct device *dev, struct page *page,
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size_t offset, size_t size,
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int direction, dma_addr_t dma_addr,
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@ -85,6 +85,7 @@ static u32 show_num_errors = 1;
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static u32 num_free_entries;
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static u32 min_free_entries;
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static u32 nr_total_entries;
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/* number of preallocated entries requested by kernel cmdline */
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static u32 req_entries;
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@ -257,6 +258,21 @@ static void add_dma_entry(struct dma_debug_entry *entry)
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put_hash_bucket(bucket, &flags);
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}
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static struct dma_debug_entry *__dma_entry_alloc(void)
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{
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struct dma_debug_entry *entry;
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entry = list_entry(free_entries.next, struct dma_debug_entry, list);
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list_del(&entry->list);
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memset(entry, 0, sizeof(*entry));
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num_free_entries -= 1;
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if (num_free_entries < min_free_entries)
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min_free_entries = num_free_entries;
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return entry;
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}
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/* struct dma_entry allocator
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*
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* The next two functions implement the allocator for
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@ -276,9 +292,7 @@ static struct dma_debug_entry *dma_entry_alloc(void)
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goto out;
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}
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entry = list_entry(free_entries.next, struct dma_debug_entry, list);
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list_del(&entry->list);
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memset(entry, 0, sizeof(*entry));
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entry = __dma_entry_alloc();
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#ifdef CONFIG_STACKTRACE
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entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
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@ -286,9 +300,6 @@ static struct dma_debug_entry *dma_entry_alloc(void)
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entry->stacktrace.skip = 2;
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save_stack_trace(&entry->stacktrace);
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#endif
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num_free_entries -= 1;
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if (num_free_entries < min_free_entries)
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min_free_entries = num_free_entries;
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out:
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spin_unlock_irqrestore(&free_entries_lock, flags);
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@ -310,6 +321,53 @@ static void dma_entry_free(struct dma_debug_entry *entry)
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spin_unlock_irqrestore(&free_entries_lock, flags);
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}
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int dma_debug_resize_entries(u32 num_entries)
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{
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int i, delta, ret = 0;
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unsigned long flags;
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struct dma_debug_entry *entry;
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LIST_HEAD(tmp);
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spin_lock_irqsave(&free_entries_lock, flags);
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if (nr_total_entries < num_entries) {
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delta = num_entries - nr_total_entries;
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spin_unlock_irqrestore(&free_entries_lock, flags);
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for (i = 0; i < delta; i++) {
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entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry)
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break;
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list_add_tail(&entry->list, &tmp);
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}
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spin_lock_irqsave(&free_entries_lock, flags);
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list_splice(&tmp, &free_entries);
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nr_total_entries += i;
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num_free_entries += i;
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} else {
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delta = nr_total_entries - num_entries;
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for (i = 0; i < delta && !list_empty(&free_entries); i++) {
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entry = __dma_entry_alloc();
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kfree(entry);
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}
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nr_total_entries -= i;
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}
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if (nr_total_entries != num_entries)
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ret = 1;
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spin_unlock_irqrestore(&free_entries_lock, flags);
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return ret;
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}
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EXPORT_SYMBOL(dma_debug_resize_entries);
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/*
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* DMA-API debugging init code
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*
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@ -490,6 +548,8 @@ void dma_debug_init(u32 num_entries)
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return;
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}
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nr_total_entries = num_free_entries;
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printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
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}
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