udmabuf: configurable list_limit and size_limit_mb

Default list_limit and size_limit_mb are not big enough to cover all
possible use cases. For example, list_limit could be well over its default,
1024 if only one or several pages are chained in all individual list entries
when creating dmabuf backed by >4MB buffer. list_limit and size_limit_mb are
now defined as module parameters so that those can be optionally configured
by root with proper values to remove these constraints.

Cc: Gerd Hoffmann <[email protected]>
Signed-off-by: Dongwon Kim <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Gerd Hoffmann <[email protected]>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 1a79ce899b0f..8df761a10251 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -13,8 +13,13 @@
 #include <linux/udmabuf.h>
 #include <linux/hugetlb.h>
 
-static const u32    list_limit = 1024;  /* udmabuf_create_list->count limit */
-static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes  */
+static int list_limit = 1024;
+module_param(list_limit, int, 0644);
+MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. Default is 1024.");
+
+static int size_limit_mb = 64;
+module_param(size_limit_mb, int, 0644);
+MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is 64.");
 
 struct udmabuf {
 	pgoff_t pagecount;