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dma-debug: add allocator code

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Impact: add allocator code for struct dma_debug_entry

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2009-01-09 12:42:46 +01:00
parent 30dfa90cc8
commit 3b1e79ed73
1 changed files with 57 additions and 0 deletions
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57
lib/dma-debug.c
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@ -52,6 +52,16 @@ struct hash_bucket {
/* Hash list to save the allocated dma addresses */
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
@ -141,3 +151,50 @@ static void add_dma_entry(struct dma_debug_entry *entry)
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);
}