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]>
dedewu6 · Jun 23, 2021 · 2e717a5 · 2e717a5
1 parent 89bcadc
commit 2e717a5
Showing 1 changed file with 7 additions and 2 deletions.
diff --git 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;