From db13db9f67fe5049159a05e870daedcee5879f8d Mon Sep 17 00:00:00 2001
From: Li RongQing <lirongqing@baidu.com>
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 <lirongqing@baidu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
[ Magnus Karlsson: rewrote changelog ]
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
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 1069c46364ffb..1719a327e5f9f 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
--
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