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>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h
index 28d53cb7b5a..171ad8aedc8 100644
--- a/include/linux/dma-debug.h
+++ b/include/linux/dma-debug.h
@@ -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,