Commit 13a9c48a authored Nov 20, 2017 by Jakub Kicinski Committed by Daniel Borkmann Nov 21, 2017

bpf: offload: add comment warning developers about double destroy



Offload state may get destroyed either because the device for which
it was constructed is going away, or because the refcount of bpf
program itself has reached 0.  In both of those cases we will call
__bpf_prog_offload_destroy() to unlink the offload from the device.
We may in fact call it twice, which works just fine, but we should
make clear this is intended and caution others trying to extend the
function.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 32a72bbd

kernel/bpf/offload.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -85,6 +85,10 @@ static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
		struct bpf_dev_offload *offload = prog->aux->offload;
		struct netdev_bpf data = {};

		/* Caution - if netdev is destroyed before the program, this function
		* will be called twice.
		*/

		data.offload.prog = prog;

		if (offload->verifier_running)

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