From db13db9f67fe5049159a05e870daedcee5879f8d Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Tue, 24 Nov 2020 15:21:14 +0800 Subject: [PATCH] libbpf: Add support for canceling cached_cons advance Add a new function for returning descriptors the user received after an xsk_ring_cons__peek call. After the application has gotten a number of descriptors from a ring, it might not be able to or want to process them all for various reasons. Therefore, it would be useful to have an interface for returning or cancelling a number of them so that they are returned to the ring. This patch adds a new function called xsk_ring_cons__cancel that performs this operation on nb descriptors counted from the end of the batch of descriptors that was received through the peek call. Signed-off-by: Li RongQing Signed-off-by: Daniel Borkmann [ Magnus Karlsson: rewrote changelog ] Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/1606202474-8119-1-git-send-email-lirongqing@baidu.com --- tools/lib/bpf/xsk.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h index 1069c46364ff..1719a327e5f9 100644 --- a/tools/lib/bpf/xsk.h +++ b/tools/lib/bpf/xsk.h @@ -153,6 +153,12 @@ static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons, return entries; } +static inline void xsk_ring_cons__cancel(struct xsk_ring_cons *cons, + size_t nb) +{ + cons->cached_cons -= nb; +} + static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, size_t nb) { /* Make sure data has been read before indicating we are done -- 2.20.1