From patchwork Sat Sep 26 01:13:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 260153 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=-14.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 CA2CEC4727C for ; Sat, 26 Sep 2020 01:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C88320878 for ; Sat, 26 Sep 2020 01:14:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="bnkG0zYP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729910AbgIZBOq (ORCPT ); Fri, 25 Sep 2020 21:14:46 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:47536 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729898AbgIZBOm (ORCPT ); Fri, 25 Sep 2020 21:14:42 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08Q1DZXT031834 for ; Fri, 25 Sep 2020 18:14:42 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=s3HW88pKP/0kazcphhCZqVfF0k8h1Gl6XFv5Xu4SUak=; b=bnkG0zYPz7NIosssyaUEZIVN70+04+9dTg8Aw7UViqZ1vl8n/nqu2dk7H0dh+WvmjZqx rRDiWgEco2D71Is7lWQ0UOtoMicfQnm6YpDeUN6Aizva4U+aYumOJ5AP3f/8iCtsfY1v JwgrrNnnqOhAGeihhlDLDRrmVKuxaMEpsIw= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 33sdm1c5fj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 25 Sep 2020 18:14:41 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 25 Sep 2020 18:14:41 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 3B9E22EC75B0; Fri, 25 Sep 2020 18:14:30 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , , Andrii Nakryiko , Arnaldo Carvalho de Melo , John Fastabend Subject: [PATCH v2 bpf-next 3/9] libbpf: generalize common logic for managing dynamically-sized arrays Date: Fri, 25 Sep 2020 18:13:51 -0700 Message-ID: <20200926011357.2366158-4-andriin@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200926011357.2366158-1-andriin@fb.com> References: <20200926011357.2366158-1-andriin@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-09-25_19:2020-09-24,2020-09-25 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=999 lowpriorityscore=0 spamscore=0 impostorscore=0 malwarescore=0 suspectscore=8 bulkscore=0 adultscore=0 phishscore=0 clxscore=1015 mlxscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009260006 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Managing dynamically-sized array is a common, but not trivial functionality, which significant amount of logic and code to implement properly. So instead of re-implementing it all the time, extract it into a helper function ans reuse. Acked-by: John Fastabend Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/btf.c | 77 ++++++++++++++++++++++++--------- tools/lib/bpf/libbpf_internal.h | 3 ++ 2 files changed, 59 insertions(+), 21 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index d180a677a3fb..f5255e2bd222 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -51,7 +51,7 @@ struct btf { /* type ID to `struct btf_type *` lookup index */ __u32 *type_offs; - __u32 type_offs_cap; + size_t type_offs_cap; __u32 nr_types; /* BTF object FD, if loaded into kernel */ @@ -66,31 +66,60 @@ static inline __u64 ptr_to_u64(const void *ptr) return (__u64) (unsigned long) ptr; } -static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +/* Ensure given dynamically allocated memory region pointed to by *data* with + * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough + * memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements + * are already used. At most *max_cnt* elements can be ever allocated. + * If necessary, memory is reallocated and all existing data is copied over, + * new pointer to the memory region is stored at *data, new memory region + * capacity (in number of elements) is stored in *cap. + * On success, memory pointer to the beginning of unused memory is returned. + * On error, NULL is returned. + */ +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt) { - /* nr_types is 1-based, so N types means we need N+1-sized array */ - if (btf->nr_types + 2 > btf->type_offs_cap) { - __u32 *new_offs; - __u32 expand_by, new_size; + size_t new_cnt; + void *new_data; - if (btf->type_offs_cap == BTF_MAX_NR_TYPES) - return -E2BIG; + if (cur_cnt + add_cnt <= *cap_cnt) + return *data + cur_cnt * elem_sz; - expand_by = max(btf->type_offs_cap / 4, 16U); - new_size = min(BTF_MAX_NR_TYPES, btf->type_offs_cap + expand_by); + /* requested more than the set limit */ + if (cur_cnt + add_cnt > max_cnt) + return NULL; - new_offs = libbpf_reallocarray(btf->type_offs, new_size, sizeof(*new_offs)); - if (!new_offs) - return -ENOMEM; + new_cnt = *cap_cnt; + new_cnt += new_cnt / 4; /* expand by 25% */ + if (new_cnt < 16) /* but at least 16 elements */ + new_cnt = 16; + if (new_cnt > max_cnt) /* but not exceeding a set limit */ + new_cnt = max_cnt; + if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */ + new_cnt = cur_cnt + add_cnt; + + new_data = libbpf_reallocarray(*data, new_cnt, elem_sz); + if (!new_data) + return NULL; - new_offs[0] = UINT_MAX; /* VOID is specially handled */ + /* zero out newly allocated portion of memory */ + memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz); - btf->type_offs = new_offs; - btf->type_offs_cap = new_size; - } + *data = new_data; + *cap_cnt = new_cnt; + return new_data + cur_cnt * elem_sz; +} - btf->type_offs[btf->nr_types + 1] = type_off; +static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off) +{ + __u32 *p; + + p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32), + btf->nr_types + 1, BTF_MAX_NR_TYPES, 1); + if (!p) + return -ENOMEM; + *p = type_off; return 0; } @@ -203,11 +232,17 @@ static int btf_parse_type_sec(struct btf *btf) struct btf_header *hdr = btf->hdr; void *next_type = btf->types_data; void *end_type = next_type + hdr->type_len; + int err, type_size; - while (next_type < end_type) { - int type_size; - int err; + /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(), + * so ensure we can never properly use its offset from index by + * setting it to a large value + */ + err = btf_add_type_idx_entry(btf, UINT_MAX); + if (err) + return err; + while (next_type < end_type) { err = btf_add_type_idx_entry(btf, next_type - btf->types_data); if (err) return err; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 4d1c366fca2c..d43ce00e0022 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -105,6 +105,9 @@ static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size) return realloc(ptr, total); } +void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, + size_t cur_cnt, size_t max_cnt, size_t add_cnt); + static inline bool libbpf_validate_opts(const char *opts, size_t opts_sz, size_t user_sz, const char *type_name)