From 44e9eb5a762142a4aa46c0b5da7c39bfeb78910e Mon Sep 17 00:00:00 2001 From: Robert Mader Date: Wed, 22 Jul 2026 13:01:45 +0200 Subject: [PATCH] dma-buf/udmabuf: Disable the size limit by default As udmabuf increasingly enjoys popularity - being used in projects like libcamera, Gstreamer, Mesa, KWin and Weston - users more frequently encounter cases where the current default size limit of 64MB is too low. Examples include allocating video buffers at a 8K resolution - and even 4K is affected when using non-subsampled video formats and high bit depths. In its current form the size limit for individual buffers does not seem to provide any additional level of protection - such as limiting the amount of memory a process can pin - as the later can just allocate multiple buffers. If additional guardrails are desired, they would likely require some kind accounting not limited to individual buffers. Therefor let's disable the size limit by default by setting it to the maximal possible value, INT_MAX. Signed-off-by: Robert Mader Acked-by: Vivek Kasireddy Link: https://lore.kernel.org/dri-devel/20260711144814.8205-1-robert.mader@collabora.com/ Link: https://lore.kernel.org/dri-devel/6764ca6f-b4d8-4baa-9d27-2ca867ac2d41@amd.com/ Signed-off-by: Vivek Kasireddy Link: https://patch.msgid.link/20260722110145.36641-1-robert.mader@collabora.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 bced421c0d65..639e93704924 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -20,9 +20,9 @@ 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; +static int size_limit_mb = INT_MAX; module_param(size_limit_mb, int, 0644); -MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is 64."); +MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is INT_MAX."); struct udmabuf { pgoff_t pagecount;