From 80348d8867c65e2c64ca78d82326e889550a24b6 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Wed, 7 Oct 2020 13:42:26 +0200 Subject: libbpf: Fix compatibility problem in xsk_socket__create Fix a compatibility problem when the old XDP_SHARED_UMEM mode is used together with the xsk_socket__create() call. In the old XDP_SHARED_UMEM mode, only sharing of the same device and queue id was allowed, and in this mode, the fill ring and completion ring were shared between the AF_XDP sockets. Therefore, it was perfectly fine to call the xsk_socket__create() API for each socket and not use the new xsk_socket__create_shared() API. This behavior was ruined by the commit introducing XDP_SHARED_UMEM support between different devices and/or queue ids. This patch restores the ability to use xsk_socket__create in these circumstances so that backward compatibility is not broken. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/1602070946-11154-1-git-send-email-magnus.karlsson@gmail.com --- tools/lib/bpf/xsk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 30b4ca5d2ac7..e3c98c007825 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -705,7 +705,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_ctx *ctx; int err, ifindex; - if (!umem || !xsk_ptr || !(rx || tx) || !fill || !comp) + if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; xsk = calloc(1, sizeof(*xsk)); @@ -735,6 +735,11 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, ctx = xsk_get_ctx(umem, ifindex, queue_id); if (!ctx) { + if (!fill || !comp) { + err = -EFAULT; + goto out_socket; + } + ctx = xsk_create_ctx(xsk, umem, ifindex, ifname, queue_id, fill, comp); if (!ctx) { -- cgit v1.2.3