netdev - [PATCH bpf-next v3] bpf/cpumap.c: Remove unnecessary TODO comment

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Message-ID: <20251021114714.1757372-1-mehdi.benhadjkhelifa@gmail.com>
Date: Tue, 21 Oct 2025 12:41:24 +0100
From: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
To: ast@...nel.org,
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	davem@...emloft.net,
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Cc: netdev@...r.kernel.org,
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	Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
Subject: [PATCH bpf-next v3] bpf/cpumap.c: Remove unnecessary TODO comment

After discussion with bpf maintainers[1], queue_index could
be propagated to the remote XDP program by the xdp_md struct[2]
which makes this todo a misguide for future effort.

[1]:https://lore.kernel.org/all/87y0q23j2w.fsf@cloudflare.com/
[2]:https://docs.ebpf.io/linux/helper-function/bpf_xdp_adjust_meta/

Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
---
Changelog:

Changes from v2:

-Corrected the new comment

Link:https://lore.kernel.org/all/20251020170254.14622-1-mehdi.benhadjkhelifa@gmail.com/

Changes from v1:

-Added a comment to clarify that RX queue_index is lost after the frame
redirection.

Link:https://lore.kernel.org/bpf/d9819687-5b0d-4bfa-9aec-aef71b847383@gmail.com/T/#mcb6a0315f174d02db3c9bc4fa556cc939c87a706

 kernel/bpf/cpumap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 703e5df1f4ef..ee37186fea35 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -195,8 +195,10 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
 
 		rxq.dev = xdpf->dev_rx;
 		rxq.mem.type = xdpf->mem_type;
-		/* TODO: report queue_index to xdp_rxq_info */
-
+		/* RX queue_index is not preserved after redirection.
+		 * If needed, the sender can embed it in XDP metadata
+		 * (via bpf_xdp_adjust_meta) for the remote program.
+		 */
 		xdp_convert_frame_to_buff(xdpf, &xdp);
 
 		act = bpf_prog_run_xdp(rcpu->prog, &xdp);
-- 
2.51.1.dirty