Re: [xdp-hints] [PATCH bpf RFC-V2 1/5] xdp: rss hash types representation
From: Toke Høiland-Jørgensen <hidden>
Date: 2023-03-29 21:47:08
Also in:
bpf, intel-wired-lan, lkml
Jesper Dangaard Brouer [off-list ref] writes:
quoted hunk ↗ jump to hunk
diff --git a/net/core/xdp.c b/net/core/xdp.c index 7133017bcd74..81d41df30695 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c@@ -721,12 +721,14 @@ __bpf_kfunc int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *tim * @hash: Return value pointer. * * Return: - * * Returns 0 on success or ``-errno`` on error. + * * Returns (positive) RSS hash **type** on success or ``-errno`` on error.
This change is going to break any BPF program that does: if (!bpf_xdp_metadata_rx_hash(ctx, &hash)) /* do something with hash */ so I think adding a second argument is better; that way, at least breakage will be explicit instead of being a hidden change in semantics (and the CO-RE style checking for kfuncs Alexei introduced should trigger correctly). But really, what we should do anyway is merge this during the -rc phase to minimise any breakage :) -Toke