dma-debug: add allocator code (3b1e79ed) · Commits · e / devices / android_kernel_fairphone_FP5

lib/dma-debug.c

+57 −0

Original line number	Original line	Diff line number	Diff line
	@@ -52,6 +52,16 @@ struct hash_bucket {

	/* Hash list to save the allocated dma addresses */		/* Hash list to save the allocated dma addresses */
	static struct hash_bucket dma_entry_hash[HASH_SIZE];		static struct hash_bucket dma_entry_hash[HASH_SIZE];
			/* List of pre-allocated dma_debug_entry's */
			static LIST_HEAD(free_entries);
			/* Lock for the list above */
			static DEFINE_SPINLOCK(free_entries_lock);

			/* Global disable flag - will be set in case of an error */
			static bool global_disable __read_mostly;

			static u32 num_free_entries;
			static u32 min_free_entries;

	/*		/*
	* Hash related functions		* Hash related functions
	@@ -141,3 +151,50 @@ static void add_dma_entry(struct dma_debug_entry *entry)
	put_hash_bucket(bucket, &flags);		put_hash_bucket(bucket, &flags);
	}		}

			/* struct dma_entry allocator
			*
			* The next two functions implement the allocator for
			* struct dma_debug_entries.
			*/
			static struct dma_debug_entry *dma_entry_alloc(void)
			{
			struct dma_debug_entry *entry = NULL;
			unsigned long flags;

			spin_lock_irqsave(&free_entries_lock, flags);

			if (list_empty(&free_entries)) {
			printk(KERN_ERR "DMA-API: debugging out of memory "
			"- disabling\n");
			global_disable = true;
			goto out;
			}

			entry = list_entry(free_entries.next, struct dma_debug_entry, list);
			list_del(&entry->list);
			memset(entry, 0, sizeof(*entry));

			num_free_entries -= 1;
			if (num_free_entries < min_free_entries)
			min_free_entries = num_free_entries;

			out:
			spin_unlock_irqrestore(&free_entries_lock, flags);

			return entry;
			}

			static void dma_entry_free(struct dma_debug_entry *entry)
			{
			unsigned long flags;

			/*
			* add to beginning of the list - this way the entries are
			* more likely cache hot when they are reallocated.
			*/
			spin_lock_irqsave(&free_entries_lock, flags);
			list_add(&entry->list, &free_entries);
			num_free_entries += 1;
			spin_unlock_irqrestore(&free_entries_lock, flags);
			}