From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFE70C433E2 for ; Wed, 31 Mar 2021 06:44:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6338619D8 for ; Wed, 31 Mar 2021 06:44:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233840AbhCaGoF (ORCPT ); Wed, 31 Mar 2021 02:44:05 -0400 Received: from mga05.intel.com ([192.55.52.43]:14630 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233780AbhCaGoC (ORCPT ); Wed, 31 Mar 2021 02:44:02 -0400 IronPort-SDR: Qr2+YHvTcUEOSAFIjdweIBlxUFyIPf4CJdznZWkyvPc94Io8wm1EUvbSsPbmkyUGjnRtG4WCVS 1Lbf2JnbTUAQ== X-IronPort-AV: E=McAfee;i="6000,8403,9939"; a="277111333" X-IronPort-AV: E=Sophos;i="5.81,293,1610438400"; d="scan'208";a="277111333" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2021 23:44:02 -0700 IronPort-SDR: xmZkpm5nC4d0w9YtcRU3LWOWZunI5pRJ46SpyPWggYevHePjkuQ75Mt+PUw5YUiCXIZRu+up4Y C9UfZy/pTsow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,293,1610438400"; d="scan'208";a="445523168" Received: from silpixa00399839.ir.intel.com (HELO localhost.localdomain) ([10.237.222.142]) by fmsmga002.fm.intel.com with ESMTP; 30 Mar 2021 23:44:00 -0700 From: Ciara Loftus To: netdev@vger.kernel.org, bpf@vger.kernel.org, magnus.karlsson@intel.com, bjorn@kernel.org, alexei.starovoitov@gmail.com Cc: Ciara Loftus Subject: [PATCH v4 bpf 2/3] libbpf: restore umem state after socket create failure Date: Wed, 31 Mar 2021 06:12:17 +0000 Message-Id: <20210331061218.1647-3-ciara.loftus@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210331061218.1647-1-ciara.loftus@intel.com> References: <20210331061218.1647-1-ciara.loftus@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org If the call to xsk_socket__create fails, the user may want to retry the socket creation using the same umem. Ensure that the umem is in the same state on exit if the call fails by: 1. ensuring the umem _save pointers are unmodified. 2. not unmapping the set of umem rings that were set up with the umem during xsk_umem__create, since those maps existed before the call to xsk_socket__create and should remain in tact even in the event of failure. Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices") Signed-off-by: Ciara Loftus --- tools/lib/bpf/xsk.c | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 443b0cfb45e8..5098d9e3b55a 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -743,26 +743,30 @@ static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex, return NULL; } -static void xsk_put_ctx(struct xsk_ctx *ctx) +static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap) { struct xsk_umem *umem = ctx->umem; struct xdp_mmap_offsets off; int err; - if (--ctx->refcount == 0) { - err = xsk_get_mmap_offsets(umem->fd, &off); - if (!err) { - munmap(ctx->fill->ring - off.fr.desc, - off.fr.desc + umem->config.fill_size * - sizeof(__u64)); - munmap(ctx->comp->ring - off.cr.desc, - off.cr.desc + umem->config.comp_size * - sizeof(__u64)); - } + if (--ctx->refcount) + return; - list_del(&ctx->list); - free(ctx); - } + if (!unmap) + goto out_free; + + err = xsk_get_mmap_offsets(umem->fd, &off); + if (err) + goto out_free; + + munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size * + sizeof(__u64)); + munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size * + sizeof(__u64)); + +out_free: + list_del(&ctx->list); + free(ctx); } static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, @@ -797,8 +801,6 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk, memcpy(ctx->ifname, ifname, IFNAMSIZ - 1); ctx->ifname[IFNAMSIZ - 1] = '\0'; - umem->fill_save = NULL; - umem->comp_save = NULL; ctx->fill = fill; ctx->comp = comp; list_add(&ctx->list, &umem->ctx_list); @@ -854,6 +856,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, struct xsk_socket *xsk; struct xsk_ctx *ctx; int err, ifindex; + bool unmap = umem->fill_save != fill; if (!umem || !xsk_ptr || !(rx || tx)) return -EFAULT; @@ -994,6 +997,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } *xsk_ptr = xsk; + umem->fill_save = NULL; + umem->comp_save = NULL; return 0; out_mmap_tx: @@ -1005,7 +1010,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, munmap(rx_map, off.rx.desc + xsk->config.rx_size * sizeof(struct xdp_desc)); out_put_ctx: - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, unmap); out_socket: if (--umem->refcount) close(xsk->fd); @@ -1071,7 +1076,7 @@ void xsk_socket__delete(struct xsk_socket *xsk) } } - xsk_put_ctx(ctx); + xsk_put_ctx(ctx, true); umem->refcount--; /* Do not close an fd that also has an associated umem connected -- 2.17.1