[PATCH v2 2/2] udmabuf: Increase the default list length limit

[Val Packett <val@invisiblethingslab.com>]

Shared memory buffers for software-rendered GUI applications are often
large and highly fragmented in memory. To get a shareable handle to such
a buffer from a guest VM, a virtio-gpu device backend can use the
UDMABUF_CREATE_LIST ioctl with the memfds backing guest RAM and the list
of guest physical pages sent by the guest driver. That list reaches 80K
entries for a maximized window on a 4K display!

Increase the default limit to 131072.

Signed-off-by: Val Packett <val@invisiblethingslab.com>
---
 drivers/dma-buf/udmabuf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 654ebe7f6b3f..dd913f9f3b06 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -16,9 +16,9 @@
 #include <linux/vmalloc.h>
 #include <linux/iosys-map.h>
 
-static int list_limit = 1024;
+static int list_limit = 131072;
 module_param(list_limit, int, 0644);
-MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. Default is 1024.");
+MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. Default is 131072.");
 
 static int size_limit_mb = INT_MAX;
 module_param(size_limit_mb, int, 0644);
-- 
2.55.0