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 kraxel@redhat.com Signed-off-by: Dongwon Kim dongwon.kim@intel.com --- drivers/dma-buf/udmabuf.c | 9 +++++++-- 1 file 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;