From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Subject: [PATCH bpf] xsk: fix poll/POLLIN premature returns Date: Mon, 23 Jul 2018 11:43:03 +0200 Message-ID: <20180723094303.6632-1-bjorn.topel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , qi.z.zhang@intel.com To: bjorn.topel@gmail.com, magnus.karlsson@intel.com, ast@fb.com, daniel@iogearbox.net, netdev@vger.kernel.org Return-path: Received: from mga17.intel.com ([192.55.52.151]:21666 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388128AbeGWKni (ORCPT ); Mon, 23 Jul 2018 06:43:38 -0400 Sender: netdev-owner@vger.kernel.org List-ID: From: Björn Töpel Polling for the ingress queues relies on reading the producer/consumer pointers of the Rx queue. Prior this commit, a cached consumer pointer could be used, instead of the actual consumer pointer and therefore report POLLIN prematurely. This patch makes sure that the non-cached consumer pointer is used instead. Reported-by: Qi Zhang Tested-by: Qi Zhang Fixes: c497176cb2e4 ("xsk: add Rx receive functions and poll support") Signed-off-by: Björn Töpel --- net/xdp/xsk_queue.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index 52ecaf770642..8a64b150be54 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -250,7 +250,7 @@ static inline bool xskq_full_desc(struct xsk_queue *q) static inline bool xskq_empty_desc(struct xsk_queue *q) { - return xskq_nb_free(q, q->prod_tail, 1) == q->nentries; + return xskq_nb_free(q, q->prod_tail, q->nentries) == q->nentries; } void xskq_set_umem(struct xsk_queue *q, struct xdp_umem_props *umem_props); -- 2.17.1