On Thu, 19 Mar 2020 14:13:13 +0100 Toke Høiland-Jørgensen wrote: > From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> > > While it is currently possible for userspace to specify that an existing > XDP program should not be replaced when attaching to an interface, there is > no mechanism to safely replace a specific XDP program with another. > > This patch adds a new netlink attribute, IFLA_XDP_EXPECTED_FD, which can be > set along with IFLA_XDP_FD. If set, the kernel will check that the program > currently loaded on the interface matches the expected one, and fail the > operation if it does not. This corresponds to a 'cmpxchg' memory operation. > > A new companion flag, XDP_FLAGS_EXPECT_FD, is also added to explicitly > request checking of the EXPECTED_FD attribute. This is needed for userspace > to discover whether the kernel supports the new attribute. > > Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> I didn't know we wanted to go ahead with this... If we do please run this thru checkpatch, set .strict_start_type, and make the expected fd unsigned. A negative expected fd makes no sense.
