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dma-debug: add dma_debug_resize_entries() to adjust the number of dma_debug_entries

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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>
This commit is contained in:
FUJITA Tomonori 2009-04-15 18:22:41 +09:00 committed by Ingo Molnar
parent 7e05575c42
commit e6a1a89d57
2 changed files with 73 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/dma-debug.h
View File

@ -32,6 +32,8 @@ extern void dma_debug_add_bus(struct bus_type *bus);
extern void dma_debug_init(u32 num_entries);
extern int dma_debug_resize_entries(u32 num_entries);
extern void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr,
@ -91,6 +93,11 @@ static inline void dma_debug_init(u32 num_entries)
{
}
static inline int dma_debug_resize_entries(u32 num_entries)
{
return 0;
}
static inline void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr,

72
lib/dma-debug.c
View File

@ -85,6 +85,7 @@ static u32 show_num_errors = 1;
static u32 num_free_entries;
static u32 min_free_entries;
static u32 nr_total_entries;
/* number of preallocated entries requested by kernel cmdline */
static u32 req_entries;
@ -257,6 +258,21 @@ static void add_dma_entry(struct dma_debug_entry *entry)
put_hash_bucket(bucket, &flags);
}
static struct dma_debug_entry *__dma_entry_alloc(void)
{
struct dma_debug_entry *entry;
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;
return entry;
}
/* struct dma_entry allocator
*
* The next two functions implement the allocator for
@ -276,9 +292,7 @@ static struct dma_debug_entry *dma_entry_alloc(void)
goto out;
}
entry = list_entry(free_entries.next, struct dma_debug_entry, list);
list_del(&entry->list);
memset(entry, 0, sizeof(*entry));
entry = __dma_entry_alloc();
#ifdef CONFIG_STACKTRACE
entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
@ -286,9 +300,6 @@ static struct dma_debug_entry *dma_entry_alloc(void)
entry->stacktrace.skip = 2;
save_stack_trace(&entry->stacktrace);
#endif
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);
@ -310,6 +321,53 @@ static void dma_entry_free(struct dma_debug_entry *entry)
spin_unlock_irqrestore(&free_entries_lock, flags);
}
int dma_debug_resize_entries(u32 num_entries)
{
int i, delta, ret = 0;
unsigned long flags;
struct dma_debug_entry *entry;
LIST_HEAD(tmp);
spin_lock_irqsave(&free_entries_lock, flags);
if (nr_total_entries < num_entries) {
delta = num_entries - nr_total_entries;
spin_unlock_irqrestore(&free_entries_lock, flags);
for (i = 0; i < delta; i++) {
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
break;
list_add_tail(&entry->list, &tmp);
}
spin_lock_irqsave(&free_entries_lock, flags);
list_splice(&tmp, &free_entries);
nr_total_entries += i;
num_free_entries += i;
} else {
delta = nr_total_entries - num_entries;
for (i = 0; i < delta && !list_empty(&free_entries); i++) {
entry = __dma_entry_alloc();
kfree(entry);
}
nr_total_entries -= i;
}
if (nr_total_entries != num_entries)
ret = 1;
spin_unlock_irqrestore(&free_entries_lock, flags);
return ret;
}
EXPORT_SYMBOL(dma_debug_resize_entries);
/*
* DMA-API debugging init code
*
@ -490,6 +548,8 @@ void dma_debug_init(u32 num_entries)
return;
}
nr_total_entries = num_free_entries;
printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
}