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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 69B2FC433E0 for ; Tue, 30 Mar 2021 15:09:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44D3961998 for ; Tue, 30 Mar 2021 15:09:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231655AbhC3PIf (ORCPT ); Tue, 30 Mar 2021 11:08:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231229AbhC3PIN (ORCPT ); Tue, 30 Mar 2021 11:08:13 -0400 Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E6CBC061574; Tue, 30 Mar 2021 08:08:13 -0700 (PDT) Received: by mail-lf1-x12a.google.com with SMTP id m12so24283286lfq.10; Tue, 30 Mar 2021 08:08:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=kizS2arIJixY618Db2OznQ3jK6lFDcDTI8/S3Ak8qoo=; b=PLv7bzr0G973AHLoGvHXBDLeN7ud8eOF3bXnY+1bX1sy5hfkrBGD06wKOGd+gAtdlI +qtlRKKZuCsWZP0Pp2bQj4D/s1kWVc7+91qIoBNK63nAw5QYY+ah5TOVq9MT/uy0yK54 /v4HVkrBf2XlCUIXtWKT6NmVa8wiHANYNaeWbvXUw+b/KX4aWL0bGQjJi7ipqiSJ1LgB WhrSpg246KHJoUgkG5m6GrSyx++3luUuk5Av7iv17uvsxkdGvbbgDEOMxdMYx4SrTgwK xmdlpZZ6QvydguxSV2kd083YLiMj97sjpS3WggA44D/eIZapUqez42pE6J+0jPOUBP1K jL8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=kizS2arIJixY618Db2OznQ3jK6lFDcDTI8/S3Ak8qoo=; b=lNJUAZ7/JNBMCxtuSQFT1CEscbZYqKN86J2lG6H3KW+2Vg1P6UgxE1id+/JN8/zcDD laGdOSuBSjf8kqJB22qpNbPlELMMbWsygWUoTQWn2065avfEj1r9uCSBlnpwlAWtow3c 6PFeL34VgukmtPkikISo1ydonQ6uC/LLJpAcuCP1zsk14Ve8A0Ji2ZlGIuCgUVq5l9z2 4+iq2hgceIbTMvmmzIazs4H4acb8ZsWYx6ugIglZeQ75JG7ZaozSnZ1C8WfbAXlEMTva v2pWwa7bwhrPTX15UPki7DwLDqxYpQLcQMl/df9CMiUgaMnzKJYYqoWDa590e+AiclJN EG0Q== X-Gm-Message-State: AOAM532kkf8uRB/g6PprziyZeXRQ+z6QcDgk+m3aQN3T5CoIpSHVVA6I b4JU1BsoCfRboVhg2BOqx30X8xQ37QtiqnZJDGg= X-Google-Smtp-Source: ABdhPJzCBNmPRHrSV1/tGsfzdA98s5V0/b97UrVajZBZuXtsyOZM493IcravlBiChxJaVQKjmH+wAqgkFQV70FxISZM= X-Received: by 2002:ac2:5ec2:: with SMTP id d2mr20815237lfq.214.1617116891953; Tue, 30 Mar 2021 08:08:11 -0700 (PDT) MIME-Version: 1.0 References: <20210330113419.4616-1-ciara.loftus@intel.com> <20210330113419.4616-3-ciara.loftus@intel.com> In-Reply-To: <20210330113419.4616-3-ciara.loftus@intel.com> From: Alexei Starovoitov Date: Tue, 30 Mar 2021 08:08:00 -0700 Message-ID: Subject: Re: [PATCH v3 bpf 2/3] libbpf: restore umem state after socket create failure To: Ciara Loftus Cc: Network Development , bpf , "Karlsson, Magnus" , bjorn@kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Mar 30, 2021 at 5:06 AM Ciara Loftus wrote: > > 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 | 29 ++++++++++++++++------------- > 1 file changed, 16 insertions(+), 13 deletions(-) > > diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c > index 443b0cfb45e8..d4991ddff05a 100644 > --- a/tools/lib/bpf/xsk.c > +++ b/tools/lib/bpf/xsk.c > @@ -743,21 +743,23 @@ 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 (unmap) { > + 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)); > + } The whole function increases indent, since it changes anyway could you write it as: { if (--ctx->refcount) return; if (!unmap) goto out_free; err = xsk_get if (err) goto out_free; munmap(); out_free: list_del free } other than this it looks fine to me. Bjorn, Magnus, please review. > } > > list_del(&ctx->list); > @@ -797,8 +799,6 @@ 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 +854,7 @@ 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 +995,8 @@ 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 +1008,7 @@ 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 +1074,7 @@ 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 >