From patchwork Tue May 11 21:00:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Denis Salopek X-Patchwork-Id: 12252045 X-Patchwork-Delegate: bpf@iogearbox.net 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,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 4ACD8C43460 for ; Tue, 11 May 2021 21:01:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10B126162B for ; Tue, 11 May 2021 21:01:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229916AbhEKVCz (ORCPT ); Tue, 11 May 2021 17:02:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbhEKVCy (ORCPT ); Tue, 11 May 2021 17:02:54 -0400 Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [IPv6:2a00:1450:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C174C061574 for ; Tue, 11 May 2021 14:01:46 -0700 (PDT) Received: by mail-ej1-x634.google.com with SMTP id s20so26279825ejr.9 for ; Tue, 11 May 2021 14:01:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sartura-hr.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WjdR4lx9fyvS9YO0hZnMNL+Z/pjyrNm7xsG3BHU2QOQ=; b=bWKFThuKBQtOH5lKK8kIfFpd51m/Kq32/5QnY5omjKElIuFlHbTWHEwQaqBBWssiQt SSkluPm/8JBrMoMPgBfd1nWQXcM0Rlm2hEvUijNRbPQG/j3g5jLBf/nHnbeDebNEzn5k zkO6N6XBaxnyvES6HVLv2Rs581xcwQcoJQE+Q3vGUE3/00RDBCXKHX0Fn7KwAkrZwdhx czsisIirhBx8TE1xxlKZIVuwRybPUUGCux765EAx/5mS0bTLCsaKgzkBdMowDs626XWQ qPYC2j1qIdMpuQAOZ7VlISJuovXpNLkbvAEE1uUnAztnkdANjyRQLYahuGOhQRxSNqPa XZGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WjdR4lx9fyvS9YO0hZnMNL+Z/pjyrNm7xsG3BHU2QOQ=; b=rIqTUiv0lDb6OPg93Hwhjzf9PJqHXjsHN3t12q72oK7mBUfJdtmSa1Wv3faAW6u4vv ujGPldcbTETMnK4qIdn+wpEnxMGaCGVvqXX6w6a3yg/5yr0+9hAGmUEGGytYq5oJmRXT Rs39e0TP0thIXbexSHWVqGKNwVVoBJCIsjziJxoHaTp6TUN2h17XO/iK9xcqF8PIpuDx EQJy+9f97Oe2YVT34Kko9i3U0YtrDSylYVJZ1Dq0i0TVZRd2+n43fzTohc/biMYsoap+ i+EAXoznp9F4yATxD3sQub3aI7SLGZ51E1uyQqcbfJMyLWBWnsYlr/mjlXxnEExmznxL +vLg== X-Gm-Message-State: AOAM530kzEQEwZUluTjFgqctYsUkMyjkf1dXOezO4tWnTtXSWfr2K+P+ +4bYxMTobE4Up7jcRrg0FmAa9Mh6f5GN5+LZjKYymuV6OhkI6C+9wqZBrDbh76hMBC2t+2Q2L3X yECS+RPLKUNvLXUvXka2WJGvS+jB557VKX6vA3vN2O1CFAVrQnyHTOA4vLXtfEWk8sg7jUn10 X-Google-Smtp-Source: ABdhPJxWqeODwff5n8IKMbbzTDrQ4eDOevAx1o9ArbS8HTwfs5gBcEC8nMrl6osO0orfopuUln908g== X-Received: by 2002:a17:907:628d:: with SMTP id nd13mr33449341ejc.299.1620766904705; Tue, 11 May 2021 14:01:44 -0700 (PDT) Received: from localhost.localdomain ([93.140.9.82]) by smtp.gmail.com with ESMTPSA id k9sm13206569eje.102.2021.05.11.14.01.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 May 2021 14:01:44 -0700 (PDT) From: Denis Salopek To: bpf@vger.kernel.org Cc: Denis Salopek , Juraj Vijtiuk , Luka Oreskovic , Luka Perkov , Yonghong Song , Andrii Nakryiko , Daniel Borkmann Subject: [PATCH v7 bpf-next 1/3] bpf: add lookup_and_delete_elem support to hashtab Date: Tue, 11 May 2021 23:00:04 +0200 Message-Id: <4d18480a3e990ffbf14751ddef0325eed3be2966.1620763117.git.denis.salopek@sartura.hr> X-Mailer: git-send-email 2.26.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Extend the existing bpf_map_lookup_and_delete_elem() functionality to hashtab map types, in addition to stacks and queues. Create a new hashtab bpf_map_ops function that does lookup and deletion of the element under the same bucket lock and add the created map_ops to bpf.h. Cc: Juraj Vijtiuk Cc: Luka Oreskovic Cc: Luka Perkov Cc: Yonghong Song Cc: Andrii Nakryiko Cc: Daniel Borkmann Signed-off-by: Denis Salopek Acked-by: Yonghong Song --- include/linux/bpf.h | 2 + include/uapi/linux/bpf.h | 13 +++++ kernel/bpf/hashtab.c | 98 ++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 34 ++++++++++-- tools/include/uapi/linux/bpf.h | 13 +++++ 5 files changed, 156 insertions(+), 4 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 02b02cb29ce2..9da98d98db25 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -69,6 +69,8 @@ struct bpf_map_ops { void *(*map_lookup_elem_sys_only)(struct bpf_map *map, void *key); int (*map_lookup_batch)(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr); + int (*map_lookup_and_delete_elem)(struct bpf_map *map, void *key, + void *value, u64 flags); int (*map_lookup_and_delete_batch)(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ec6d85a81744..c10ba06af69e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -527,6 +527,15 @@ union bpf_iter_link_info { * Look up an element with the given *key* in the map referred to * by the file descriptor *fd*, and if found, delete the element. * + * For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map + * types, the *flags* argument needs to be set to 0, but for other + * map types, it may be specified as: + * + * **BPF_F_LOCK** + * Look up and delete the value of a spin-locked map + * without returning the lock. This must be specified if + * the elements contain a spinlock. + * * The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types * implement this command as a "pop" operation, deleting the top * element rather than one corresponding to *key*. @@ -536,6 +545,10 @@ union bpf_iter_link_info { * This command is only valid for the following map types: * * **BPF_MAP_TYPE_QUEUE** * * **BPF_MAP_TYPE_STACK** + * * **BPF_MAP_TYPE_HASH** + * * **BPF_MAP_TYPE_PERCPU_HASH** + * * **BPF_MAP_TYPE_LRU_HASH** + * * **BPF_MAP_TYPE_LRU_PERCPU_HASH** * * Return * Returns zero on success. On error, -1 is returned and *errno* diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index d7ebb12ffffc..9da0a0413a53 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1401,6 +1401,100 @@ static void htab_map_seq_show_elem(struct bpf_map *map, void *key, rcu_read_unlock(); } +static int __htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key, + void *value, bool is_lru_map, + bool is_percpu, u64 flags) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + struct hlist_nulls_head *head; + unsigned long bflags; + struct htab_elem *l; + u32 hash, key_size; + struct bucket *b; + int ret; + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + b = __select_bucket(htab, hash); + head = &b->head; + + ret = htab_lock_bucket(htab, b, hash, &bflags); + if (ret) + return ret; + + l = lookup_elem_raw(head, hash, key, key_size); + if (!l) { + ret = -ENOENT; + } else { + if (is_percpu) { + u32 roundup_value_size = round_up(map->value_size, 8); + void __percpu *pptr; + int off = 0, cpu; + + pptr = htab_elem_get_ptr(l, key_size); + for_each_possible_cpu(cpu) { + bpf_long_memcpy(value + off, + per_cpu_ptr(pptr, cpu), + roundup_value_size); + off += roundup_value_size; + } + } else { + u32 roundup_key_size = round_up(map->key_size, 8); + + if (flags & BPF_F_LOCK) + copy_map_value_locked(map, value, l->key + + roundup_key_size, + true); + else + copy_map_value(map, value, l->key + + roundup_key_size); + check_and_init_map_lock(map, value); + } + + hlist_nulls_del_rcu(&l->hash_node); + if (!is_lru_map) + free_htab_elem(htab, l); + } + + htab_unlock_bucket(htab, b, hash, bflags); + + if (is_lru_map && l) + bpf_lru_push_free(&htab->lru, &l->lru_node); + + return ret; +} + +static int htab_map_lookup_and_delete_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + return __htab_map_lookup_and_delete_elem(map, key, value, false, false, + flags); +} + +static int htab_percpu_map_lookup_and_delete_elem(struct bpf_map *map, + void *key, void *value, + u64 flags) +{ + return __htab_map_lookup_and_delete_elem(map, key, value, false, true, + flags); +} + +static int htab_lru_map_lookup_and_delete_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + return __htab_map_lookup_and_delete_elem(map, key, value, true, false, + flags); +} + +static int htab_lru_percpu_map_lookup_and_delete_elem(struct bpf_map *map, + void *key, void *value, + u64 flags) +{ + return __htab_map_lookup_and_delete_elem(map, key, value, true, true, + flags); +} + static int __htab_map_lookup_and_delete_batch(struct bpf_map *map, const union bpf_attr *attr, @@ -1934,6 +2028,7 @@ const struct bpf_map_ops htab_map_ops = { .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, .map_lookup_elem = htab_map_lookup_elem, + .map_lookup_and_delete_elem = htab_map_lookup_and_delete_elem, .map_update_elem = htab_map_update_elem, .map_delete_elem = htab_map_delete_elem, .map_gen_lookup = htab_map_gen_lookup, @@ -1954,6 +2049,7 @@ const struct bpf_map_ops htab_lru_map_ops = { .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, .map_lookup_elem = htab_lru_map_lookup_elem, + .map_lookup_and_delete_elem = htab_lru_map_lookup_and_delete_elem, .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys, .map_update_elem = htab_lru_map_update_elem, .map_delete_elem = htab_lru_map_delete_elem, @@ -2077,6 +2173,7 @@ const struct bpf_map_ops htab_percpu_map_ops = { .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, .map_lookup_elem = htab_percpu_map_lookup_elem, + .map_lookup_and_delete_elem = htab_percpu_map_lookup_and_delete_elem, .map_update_elem = htab_percpu_map_update_elem, .map_delete_elem = htab_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, @@ -2096,6 +2193,7 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, .map_lookup_elem = htab_lru_percpu_map_lookup_elem, + .map_lookup_and_delete_elem = htab_lru_percpu_map_lookup_and_delete_elem, .map_update_elem = htab_lru_percpu_map_update_elem, .map_delete_elem = htab_lru_map_delete_elem, .map_seq_show_elem = htab_percpu_map_seq_show_elem, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 941ca06d9dfa..d1c51da2f477 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1468,7 +1468,7 @@ int generic_map_lookup_batch(struct bpf_map *map, return err; } -#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD value +#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD flags static int map_lookup_and_delete_elem(union bpf_attr *attr) { @@ -1484,6 +1484,9 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM)) return -EINVAL; + if (attr->flags & ~BPF_F_LOCK) + return -EINVAL; + f = fdget(ufd); map = __bpf_map_get(f); if (IS_ERR(map)) @@ -1494,24 +1497,47 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) goto err_put; } + if (attr->flags && + (map->map_type == BPF_MAP_TYPE_QUEUE || + map->map_type == BPF_MAP_TYPE_STACK)) { + err = -EINVAL; + goto err_put; + } + + if ((attr->flags & BPF_F_LOCK) && + !map_value_has_spin_lock(map)) { + err = -EINVAL; + goto err_put; + } + key = __bpf_copy_key(ukey, map->key_size); if (IS_ERR(key)) { err = PTR_ERR(key); goto err_put; } - value_size = map->value_size; + value_size = bpf_map_value_size(map); err = -ENOMEM; value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); if (!value) goto free_key; + err = -ENOTSUPP; if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) { err = map->ops->map_pop_elem(map, value); - } else { - err = -ENOTSUPP; + } else if (map->map_type == BPF_MAP_TYPE_HASH || + map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { + if (!bpf_map_is_dev_bound(map)) { + bpf_disable_instrumentation(); + rcu_read_lock(); + err = map->ops->map_lookup_and_delete_elem(map, key, value, attr->flags); + rcu_read_unlock(); + bpf_enable_instrumentation(); + } } if (err) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index ec6d85a81744..c10ba06af69e 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -527,6 +527,15 @@ union bpf_iter_link_info { * Look up an element with the given *key* in the map referred to * by the file descriptor *fd*, and if found, delete the element. * + * For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map + * types, the *flags* argument needs to be set to 0, but for other + * map types, it may be specified as: + * + * **BPF_F_LOCK** + * Look up and delete the value of a spin-locked map + * without returning the lock. This must be specified if + * the elements contain a spinlock. + * * The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types * implement this command as a "pop" operation, deleting the top * element rather than one corresponding to *key*. @@ -536,6 +545,10 @@ union bpf_iter_link_info { * This command is only valid for the following map types: * * **BPF_MAP_TYPE_QUEUE** * * **BPF_MAP_TYPE_STACK** + * * **BPF_MAP_TYPE_HASH** + * * **BPF_MAP_TYPE_PERCPU_HASH** + * * **BPF_MAP_TYPE_LRU_HASH** + * * **BPF_MAP_TYPE_LRU_PERCPU_HASH** * * Return * Returns zero on success. On error, -1 is returned and *errno*