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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 190CAC5B579 for ; Fri, 28 Jun 2019 18:00:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E37F92083B for ; Fri, 28 Jun 2019 18:00:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=fomichev-me.20150623.gappssmtp.com header.i=@fomichev-me.20150623.gappssmtp.com header.b="Itbje9RP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726694AbfF1SAM (ORCPT ); Fri, 28 Jun 2019 14:00:12 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:43750 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726443AbfF1SAL (ORCPT ); Fri, 28 Jun 2019 14:00:11 -0400 Received: by mail-pl1-f195.google.com with SMTP id cl9so3639562plb.10 for ; Fri, 28 Jun 2019 11:00:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fomichev-me.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=jYb3HeTQfcaIFWpL/ma+nS5IiqOCQX6f79nGlje2oxI=; b=Itbje9RPJpvc2oL309mj4r5ADr6AXFyHyPGFhgT3L4XivbJatLbHk/H9vuuGSIdfpG GoZuemy4B6JdFXIxsKYMoWoIV74tzblZ1yDwoKdX7luhTsliuGQkuJDBMzOJ3Cwd0Ht5 /ZHeT4Z5S8uf4OVP9GG+LMdZuvZLGNxLOPo8BPwD0r/A8nsOEQsYxrlPj/WDe/5/7yWC aQ/rKaIFwVf+0h+Oxc1JLdCqcRaVMEx7Hleb+9mbaVeYnM/bJedInsdZZCGVvQG0ewID anDtGZiw7kx9nPeSxSIRbRBsnkBIANpkR6pzHwA7cnGDWipqDVWMSnFqf1/qHgfAdjt8 5Z8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=jYb3HeTQfcaIFWpL/ma+nS5IiqOCQX6f79nGlje2oxI=; b=tiexGr09GCiP0LZb6QZKShkm832GLwBomW5tr8Wg2WiFmuE2K4KiDuBZD0DS4HQJBP 3Wi/zUqYJrx1ZrhDmXT6kNalOqcnH/VNbrf9gUUDDa5VCXUpNKBgK18lRGJ14IVKe2Sh LCrj/N/V5DAlzsEgSHzsV4W+uLL9y5asJ2MsvUbUEj0dGb2bLVAD0RaL55H/nPQk7aRR M+4pSx+W+Bl6e0FCtriI5FRoqusSPyuFp1h57uTiZLzETErMO9IC/r8mcMQ60xcWL6Fs beg44EXQgf317jrkq3rB1RQd+DCMRu3tVbYyfthu1nl4NUn2pOrTD7/1QG/vbKhm8ZeK eUYQ== X-Gm-Message-State: APjAAAWqIaugnpimvPSsSxxJhTZFp03al+tiaXgOyWfNiZTdnybNJt+m buzGwF+MnJWMORTgjb0Oa/P6Og== X-Google-Smtp-Source: APXvYqzEP5dTno6gpjCzfyor7yx+9fSqCOrt0Ek/QInu8yUiEyEOqUOSZfq1IzDye50dhd+/WN0wEw== X-Received: by 2002:a17:902:9a85:: with SMTP id w5mr11538718plp.221.1561744811267; Fri, 28 Jun 2019 11:00:11 -0700 (PDT) Received: from localhost ([2601:646:8f00:18d9:d0fa:7a4b:764f:de48]) by smtp.gmail.com with ESMTPSA id w16sm3666140pfj.85.2019.06.28.11.00.10 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 28 Jun 2019 11:00:10 -0700 (PDT) Date: Fri, 28 Jun 2019 11:00:10 -0700 From: Stanislav Fomichev To: Andrii Nakryiko Cc: andrii.nakryiko@gmail.com, ast@fb.com, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH v3 bpf-next 3/9] libbpf: add ability to attach/detach BPF program to perf event Message-ID: <20190628180010.GA24308@mini-arch> References: <20190628055303.1249758-1-andriin@fb.com> <20190628055303.1249758-4-andriin@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190628055303.1249758-4-andriin@fb.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 06/27, Andrii Nakryiko wrote: > bpf_program__attach_perf_event allows to attach BPF program to existing > perf event hook, providing most generic and most low-level way to attach BPF > programs. It returns struct bpf_link, which should be passed to > bpf_link__destroy to detach and free resources, associated with a link. > > Signed-off-by: Andrii Nakryiko > --- > tools/lib/bpf/libbpf.c | 58 ++++++++++++++++++++++++++++++++++++++++ > tools/lib/bpf/libbpf.h | 3 +++ > tools/lib/bpf/libbpf.map | 1 + > 3 files changed, 62 insertions(+) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 455795e6f8af..606705f878ba 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -3958,6 +3959,63 @@ int bpf_link__destroy(struct bpf_link *link) > return err; > } > > +struct bpf_link_fd { > + struct bpf_link link; /* has to be at the top of struct */ > + int fd; /* hook FD */ > +}; > + > +static int bpf_link__destroy_perf_event(struct bpf_link *link) > +{ > + struct bpf_link_fd *l = (void *)link; > + int err; > + > + if (l->fd < 0) > + return 0; > + > + err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0); > + close(l->fd); > + return err; Why not return -errno from ioctl here (as you do elsewhere)? > +} > + > +struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, > + int pfd) > +{ > + char errmsg[STRERR_BUFSIZE]; > + struct bpf_link_fd *link; > + int bpf_fd, err; > + > + bpf_fd = bpf_program__fd(prog); > + if (bpf_fd < 0) { > + pr_warning("program '%s': can't attach before loaded\n", > + bpf_program__title(prog, false)); > + return ERR_PTR(-EINVAL); > + } > + > + link = malloc(sizeof(*link)); > + if (!link) > + return ERR_PTR(-ENOMEM); > + link->link.destroy = &bpf_link__destroy_perf_event; > + link->fd = pfd; > + > + if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, bpf_fd) < 0) { > + err = -errno; > + free(link); > + pr_warning("program '%s': failed to attach to pfd %d: %s\n", > + bpf_program__title(prog, false), pfd, > + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); > + return ERR_PTR(err); > + } > + if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) { > + err = -errno; > + free(link); > + pr_warning("program '%s': failed to enable pfd %d: %s\n", > + bpf_program__title(prog, false), pfd, > + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); > + return ERR_PTR(err); > + } > + return (struct bpf_link *)link; > +} > + > enum bpf_perf_event_ret > bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size, > void **copy_mem, size_t *copy_size, > diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h > index 5082a5ebb0c2..1bf66c4a9330 100644 > --- a/tools/lib/bpf/libbpf.h > +++ b/tools/lib/bpf/libbpf.h > @@ -169,6 +169,9 @@ struct bpf_link; > > LIBBPF_API int bpf_link__destroy(struct bpf_link *link); > > +LIBBPF_API struct bpf_link * > +bpf_program__attach_perf_event(struct bpf_program *prog, int pfd); > + > struct bpf_insn; > > /* > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map > index 3cde850fc8da..756f5aa802e9 100644 > --- a/tools/lib/bpf/libbpf.map > +++ b/tools/lib/bpf/libbpf.map > @@ -169,6 +169,7 @@ LIBBPF_0.0.4 { > global: > bpf_link__destroy; > bpf_object__load_xattr; > + bpf_program__attach_perf_event; > btf_dump__dump_type; > btf_dump__free; > btf_dump__new; > -- > 2.17.1 >