From patchwork Tue Nov 19 01:43:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brian Vazquez X-Patchwork-Id: 1197114 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="EsyI/y8H"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47H7sq2xvRz9sPc for ; Tue, 19 Nov 2019 12:44:31 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727354AbfKSBo3 (ORCPT ); Mon, 18 Nov 2019 20:44:29 -0500 Received: from mail-pg1-f201.google.com ([209.85.215.201]:57097 "EHLO mail-pg1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727351AbfKSBo2 (ORCPT ); Mon, 18 Nov 2019 20:44:28 -0500 Received: by mail-pg1-f201.google.com with SMTP id 11so14549592pgm.23 for ; Mon, 18 Nov 2019 17:44:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=TGbc4UYmRf3AIzfdB0f1oEXJDOp22zfyq9+MWMaouTg=; b=EsyI/y8Hh7UxwOmSA2KKVYqPLi4XcZJu4JyJR9OBP3iZOgWtSwgWMnEElpmqvLkOkg 10QyR87LgFTrx6aEs6l02+cJmD/hwNrvWlDVBA3I4Cep1bQ7qddkZrxamYj1BqwKgkkN SiV6XHRYEyEyY81QF2rndPK2qf0PMLEag//WPyQn3q+DacVVveMLawId5LAKmD7ywFnj 2xN/n9rG7dviMYpHE39bqSYnG/ge15P0nvHAH1F1wISj3gMucz8S3x/URG8upi9MqYR5 SV11ZvCt/JhSrb7bn0PN3zz2QhXI2qCvyaEWG0uIIrlZAd1pN2KyA6YoJIEIMjy8JILq 4OjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=TGbc4UYmRf3AIzfdB0f1oEXJDOp22zfyq9+MWMaouTg=; b=EjtYaTfszla+qlKe4iRvvse6reObr9xa7cIqa5UFYMqaRwRNw6dPY7MBw+lILQbNlr /7pfn5Fnn9tqyZVArUlTgVOzF5IRkR8ABrObV698rUIyKmPSk6dTUGQSy6Y53A30T47Y KkLuiNX3wjGdERhaJ9oTeyDs4O2P4dfdQzPJER9dg1YdpzMrWnlJ5In4XiKMIQBQx212 +1sF9AdJeYvtvznX5rbaNyn5dSX7g63NUxEnO7Hb45qNx3wkFLzMKK+tawJ5otZ4Yeix t6g5gOuyGcp5CpJazAYzhJO2yKC/CplQURihXL+TJp5KJRgSQVhO3C1KdUuaH8kOcaOc URRQ== X-Gm-Message-State: APjAAAXCgnFIv00lEEUZpWedCxaMiWHNsplJEaGENCuAwAs9pCP4jDaL 4wPGxIihRcxelgg0OKKitNt8jy/zMQWl X-Google-Smtp-Source: APXvYqyrLmPvNrNFt38sP32yCkbqZk7/MmTRGRY+13oYQfKfyai8V7oYGC6Y3mqZroyw4JRzis8g0GrjuZg0 X-Received: by 2002:a63:db13:: with SMTP id e19mr2575692pgg.233.1574127866476; Mon, 18 Nov 2019 17:44:26 -0800 (PST) Date: Mon, 18 Nov 2019 17:43:53 -0800 In-Reply-To: <20191119014357.98465-1-brianvv@google.com> Message-Id: <20191119014357.98465-6-brianvv@google.com> Mime-Version: 1.0 References: <20191119014357.98465-1-brianvv@google.com> X-Mailer: git-send-email 2.24.0.432.g9d3f5f5b63-goog Subject: [PATCH bpf-next 5/9] bpf: add batch ops to all htab bpf map From: Brian Vazquez To: Brian Vazquez , Alexei Starovoitov , Daniel Borkmann , "David S . Miller" Cc: Yonghong Song , Stanislav Fomichev , Petar Penkov , Willem de Bruijn , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Brian Vazquez Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Yonghong Song htab can't use generic batch support due some problematic behaviours inherent to the datastructre, i.e. while iterating the bpf map a concurrent program might delete the next entry that batch was about to use, in this case there's no easy solution to retrieve the next entry and the issua has been discussed multiple times (see [1] and [2]). The only way hmap can be traversed without the problem previously exposed is by making sure that the map is traversing entire buckets. This commit implements those strict requirements for hmap, the implementation follows the same interaction that generic support with some exceptions: - If keys/values buffer are not big enough to traverse a bucket, ENOSPC will be returned. - out_batch contains the value of the next bucket in the iteration, not the next key, but this is transparent for the user since the user should never use out_batch for other than bpf batch syscalls. Note that only lookup and lookup_and_delete batch ops require the hmap specific implementation and update/delete batch ops can be the generic ones. [1] https://lore.kernel.org/bpf/20190724165803.87470-1-brianvv@google.com/ [2] https://lore.kernel.org/bpf/20190906225434.3635421-1-yhs@fb.com/ Co-authored-by: Brian Vazquez Signed-off-by: Brian Vazquez Signed-off-by: Yonghong Song --- kernel/bpf/hashtab.c | 244 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 244 insertions(+) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 22066a62c8c97..3402174b292ea 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -17,6 +17,17 @@ (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \ BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED) +#define BATCH_OPS(_name) \ + .map_lookup_batch = \ + _name##_map_lookup_batch, \ + .map_lookup_and_delete_batch = \ + _name##_map_lookup_and_delete_batch, \ + .map_update_batch = \ + generic_map_update_batch, \ + .map_delete_batch = \ + generic_map_delete_batch + + struct bucket { struct hlist_nulls_head head; raw_spinlock_t lock; @@ -1232,6 +1243,235 @@ static void htab_map_seq_show_elem(struct bpf_map *map, void *key, rcu_read_unlock(); } +static int +__htab_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr, + bool do_delete, bool is_lru_map, + bool is_percpu) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + u32 bucket_cnt, total, key_size, value_size, roundup_key_size; + void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val; + void __user *ukeys, *uvalues, *ubatch; + u64 elem_map_flags, map_flags; + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + u32 batch, max_count, size; + unsigned long flags; + struct htab_elem *l; + struct bucket *b; + int ret = 0; + + max_count = attr->batch.count; + if (!max_count) + return 0; + + elem_map_flags = attr->batch.elem_flags; + if ((elem_map_flags & ~BPF_F_LOCK) || + ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map))) + return -EINVAL; + + map_flags = attr->batch.flags; + if (map_flags) + return -EINVAL; + + batch = 0; + ubatch = u64_to_user_ptr(attr->batch.in_batch); + if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch))) + return -EFAULT; + + if (batch >= htab->n_buckets) + return -ENOENT; + + /* We cannot do copy_from_user or copy_to_user inside + * the rcu_read_lock. Allocate enough space here. + */ + key_size = htab->map.key_size; + roundup_key_size = round_up(htab->map.key_size, 8); + value_size = htab->map.value_size; + size = round_up(value_size, 8); + if (is_percpu) + value_size = size * num_possible_cpus(); + keys = kvmalloc(key_size * max_count, GFP_USER | __GFP_NOWARN); + values = kvmalloc(value_size * max_count, GFP_USER | __GFP_NOWARN); + if (!keys || !values) { + ret = -ENOMEM; + goto out; + } + + dst_key = keys; + dst_val = values; + total = 0; + + preempt_disable(); + this_cpu_inc(bpf_prog_active); + rcu_read_lock(); + +again: + b = &htab->buckets[batch]; + head = &b->head; + raw_spin_lock_irqsave(&b->lock, flags); + + bucket_cnt = 0; + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) + bucket_cnt++; + + if (bucket_cnt > (max_count - total)) { + if (total == 0) + ret = -ENOSPC; + goto after_loop; + } + + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) { + memcpy(dst_key, l->key, key_size); + + if (is_percpu) { + int off = 0, cpu; + void __percpu *pptr; + + pptr = htab_elem_get_ptr(l, map->key_size); + for_each_possible_cpu(cpu) { + bpf_long_memcpy(dst_val + off, + per_cpu_ptr(pptr, cpu), size); + off += size; + } + } else { + value = l->key + roundup_key_size; + if (elem_map_flags & BPF_F_LOCK) + copy_map_value_locked(map, dst_val, value, + true); + else + copy_map_value(map, dst_val, value); + check_and_init_map_lock(map, dst_val); + } + dst_key += key_size; + dst_val += value_size; + total++; + } + + if (do_delete) { + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) { + hlist_nulls_del_rcu(&l->hash_node); + if (is_lru_map) + bpf_lru_push_free(&htab->lru, &l->lru_node); + else + free_htab_elem(htab, l); + } + } + + batch++; + if (batch >= htab->n_buckets) { + ret = -ENOENT; + goto after_loop; + } + + raw_spin_unlock_irqrestore(&b->lock, flags); + goto again; + +after_loop: + raw_spin_unlock_irqrestore(&b->lock, flags); + + rcu_read_unlock(); + this_cpu_dec(bpf_prog_active); + preempt_enable(); + + if (ret && ret != -ENOENT) + goto out; + + /* copy data back to user */ + ukeys = u64_to_user_ptr(attr->batch.keys); + uvalues = u64_to_user_ptr(attr->batch.values); + ubatch = u64_to_user_ptr(attr->batch.out_batch); + if (copy_to_user(ubatch, &batch, sizeof(batch)) || + copy_to_user(ukeys, keys, total * key_size) || + copy_to_user(uvalues, values, total * value_size) || + put_user(total, &uattr->batch.count)) + ret = -EFAULT; + +out: + kvfree(keys); + kvfree(values); + return ret; +} + +static int +htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + false, true); +} + +static int +htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + false, true); +} + +static int +htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + false, false); +} + +static int +htab_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + false, false); +} + +static int +htab_map_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return generic_map_delete_batch(map, attr, uattr); +} + +static int +htab_lru_percpu_map_lookup_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + true, true); +} + +static int +htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + true, true); +} + +static int +htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + true, false); +} + +static int +htab_lru_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + true, false); +} + const struct bpf_map_ops htab_map_ops = { .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, @@ -1242,6 +1482,7 @@ const struct bpf_map_ops htab_map_ops = { .map_delete_elem = htab_map_delete_elem, .map_gen_lookup = htab_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, + BATCH_OPS(htab), }; const struct bpf_map_ops htab_lru_map_ops = { @@ -1255,6 +1496,7 @@ const struct bpf_map_ops htab_lru_map_ops = { .map_delete_elem = htab_lru_map_delete_elem, .map_gen_lookup = htab_lru_map_gen_lookup, .map_seq_show_elem = htab_map_seq_show_elem, + BATCH_OPS(htab_lru), }; /* Called from eBPF program */ @@ -1368,6 +1610,7 @@ const struct bpf_map_ops htab_percpu_map_ops = { .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, + BATCH_OPS(htab_percpu), }; const struct bpf_map_ops htab_lru_percpu_map_ops = { @@ -1379,6 +1622,7 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { .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, + BATCH_OPS(htab_lru_percpu), }; static int fd_htab_map_alloc_check(union bpf_attr *attr)