From 69c5d6bea7cc2168a2a483d232aa9a77202173f0 Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Tue, 16 Jul 2024 17:46:09 +0200

Subject: [PATCH] rules: Add uaccess tag to /dev/udmabuf

In some cases userspace may need to create dmabuffers from userspace

on such example is the software ISP part of libcamera which needs to

allocate dma-buffers for the output of the software ISP.

At first the plan was to allow console users access to /dev/dma_heap/*,

this was discussed with various kernel folks here:

https://lore.kernel.org/all/bb372250-e8b8-4458-bc99-dd8365b06991@redhat.com/

Giving console users access to the dma_heap's was deemed a bad idea

because memory allocated this way is not accounted in cgroup limits.

Giving access to /dev/udmabuf OTOH was deemed acceptable so that

is what this patch adds.

Resolves: #32662

---

 rules.d/70-uaccess.rules.in | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/rules.d/70-uaccess.rules.in b/rules.d/70-uaccess.rules.in

index b82ce04a39d38..e683bb1114461 100644

--- a/rules.d/70-uaccess.rules.in

+++ b/rules.d/70-uaccess.rules.in

@@ -34,6 +34,8 @@ SUBSYSTEM=="sound", TAG+="uaccess", \

 SUBSYSTEM=="video4linux", TAG+="uaccess"

 SUBSYSTEM=="dvb", TAG+="uaccess"

 SUBSYSTEM=="media", TAG+="uaccess"

+# libcamera software ISP used with some cams requires udmabuf access

+KERNEL=="udmabuf", TAG+="uaccess"

 # industrial cameras, some webcams, camcorders, set-top boxes, TV sets, audio devices, and more

 SUBSYSTEM=="firewire", TEST=="units", ENV{IEEE1394_UNIT_FUNCTION_MIDI}=="1", TAG+="uaccess"