From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7CF60334C17 for ; Thu, 5 Feb 2026 07:02:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770274935; cv=none; b=UuFFBe+NZuCqzqs92tihu+ocrrjGjlgmLw0kSuxNxxNt9knp6w79L25TWMx2+hop6XDse6/6g/5ji2IMupm6gZdqrXle/AJgAzmTlTF+y1P3/wHtMAqmh89XPtibw+1zxXJNjipjdcos4/zrAdXE4At2456T3et6dyw0WgtNKYA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770274935; c=relaxed/simple; bh=GrLV5gijxoE7NSW6SK7VgXZ5qFlInWugStQsPetpfKI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Qyq0klTlVsAqu/LMSh+R6qClmjoE1b/0yrWG74alifKTqI50Rf+BlrK4IOmbaQEP2jbO6phVpT6Omc7Ay0OR1xtWeIEDAGpBsIFgx8kjHt9pD+s+5oHifLKjA44Ma+aUfHvPE9JsEBRjYVXyLf+0ZfoTYHTsZjswKeWKsetI9jQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=fIhkbrL3; arc=none smtp.client-ip=209.85.210.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fIhkbrL3" Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-823210d1d8eso370999b3a.1 for ; Wed, 04 Feb 2026 23:02:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770274935; x=1770879735; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=+wyGHQfdqlOcSTajpA9fKceqwUXV3jdUWCFJw8oPo2A=; b=fIhkbrL3Jlrzkzo24mcwFs1OgalwdX6mVngUK3u70E8kRBSKu2UOZd55VRx5sxKQiC aF+sC62ltb1Vx8yV1BamkZbl/wS/GM3xC+YlnDkhs4mFEdcZ5sHG0DlhStsIfOEojANp fjiuGNddLY4TTJEpncbJh4TQJk+4/c68IKbdcaIOjWAJa0dXyVvWigkOCC6kTDZpT4rn AnMf19hynijYsqCIdFfeMw6Uch7DGzLsGJilTaNzwbr1ttOA4c6MOiph121pvXjv2evw gHDm5MiHaQVWIgooJVuLkWRyfGEu5GN5BXTRCiEXSbpO0/DJHd6VenFvYrK9Xv8c56uQ N9Kw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770274935; x=1770879735; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=+wyGHQfdqlOcSTajpA9fKceqwUXV3jdUWCFJw8oPo2A=; b=xPA3B7TN6kLRzsBd19L5hBtgIxtoYuNx/OLZH6o3j1pW9GbZZmIMxNiJoGuD2NYWRi Ox0CXeZp83o/LEyK2LzxwqAU3Zdi6YtF/kEsunti+d6m0hlSo8Ahh0p6Hb4Xe4EodmkY WXHWBA+vKAVO/W1pacD0naTpWVBZGwLcUVBid66ZtCfzucwW7C/ZkOmzzABDhlh7pedu J1N3kEoKytbwCmafnyb6e+taFyBHj1BDwJUZmHv52FQh+TWvNk1v7S5g9LwoR/fzKKgE JRKccUWH5NTknFLzUj1jZ5qGpHcNiMRa9H3FOWycv0yajcVp2IFBxDe0d3Id/ubmvOBA EGLw== X-Gm-Message-State: AOJu0Yyr7vI+VIVsPfklqD8boxQn3uyq+BsPJMDXyIDc41iWOB5WM739 6U8rGTkCFB6TdvWEoqMy3CX/gnTEVbtOmRo/jQcmdKzvMsvhIzNmIt7T X-Gm-Gg: AZuq6aKdgGzK4J/OmN/QQs5ti57VW3wrGn5uHNX+jvtWVAo4+yb2e86OpSVtdBg5bpX PFWBBxRh0RNRg+ZrzBvCZa1kpDwbTyL3xvbCrZgxSxjqsML0lqJ8sUTYDOQRwjM8a1Uhu0czhuD YQ+1wYyHVyB42vUDcxD0kQQ8wCmB8cg8UKNJD/CQTRBcC3goUxMBhX2bg0u7KYiXoRGtxVPgJZ0 uUtJUDtM3u+GUrTiZpzPkWINzKUw8Q94WRVoX4wxpomho44EVwEfXJj7dQBu4hualtnw+PkAsmh kPO4e+7KYqVO4DDKLoxi51No5NmJpEpQDsrN/pZFFmsaNZoRPi4xpuumEL0Vc3UZFpxbt/QUzde x+i5Ltd9OYXrRkn04JRKVLIhTNwWAFxnaWxYCDZ+qBUontwClBt/2bvyfWkU/d24Yylh87g1LJl C9Ag== X-Received: by 2002:a05:6a00:1a8f:b0:81f:b97:14a with SMTP id d2e1a72fcca58-8241c695d07mr5381155b3a.61.1770274934666; Wed, 04 Feb 2026 23:02:14 -0800 (PST) Received: from localhost ([2a03:2880:ff:57::]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8241d4af6e4sm4669777b3a.66.2026.02.04.23.02.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Feb 2026 23:02:14 -0800 (PST) From: Amery Hung To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com, andrii@kernel.org, daniel@iogearbox.net, memxor@gmail.com, martin.lau@kernel.org, kpsingh@kernel.org, yonghong.song@linux.dev, song@kernel.org, haoluo@google.com, ameryhung@gmail.com, kernel-team@meta.com Subject: [PATCH bpf-next v6 04/17] bpf: Convert bpf_selem_unlink to failable Date: Wed, 4 Feb 2026 23:01:53 -0800 Message-ID: <20260205070208.186382-5-ameryhung@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260205070208.186382-1-ameryhung@gmail.com> References: <20260205070208.186382-1-ameryhung@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To prepare changing both bpf_local_storage_map_bucket::lock and bpf_local_storage::lock to rqspinlock, convert bpf_selem_unlink() to failable. It still always succeeds and returns 0 until the change happens. No functional change. Open code bpf_selem_unlink_storage() in the only caller, bpf_selem_unlink(), since unlink_map and unlink_storage must be done together after all the necessary locks are acquired. For bpf_local_storage_map_free(), ignore the return from bpf_selem_unlink() for now. A later patch will allow it to unlink selems even when failing to acquire locks. Signed-off-by: Amery Hung --- include/linux/bpf_local_storage.h | 2 +- kernel/bpf/bpf_cgrp_storage.c | 3 +- kernel/bpf/bpf_inode_storage.c | 4 +- kernel/bpf/bpf_local_storage.c | 71 +++++++++++++++---------------- kernel/bpf/bpf_task_storage.c | 4 +- net/core/bpf_sk_storage.c | 4 +- 6 files changed, 39 insertions(+), 49 deletions(-) diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 709506e982a6..f74e0f7656a1 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -176,7 +176,7 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map, void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem); -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); int bpf_selem_link_map(struct bpf_local_storage_map *smap, struct bpf_local_storage *local_storage, diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index 0687a760974a..8fef24fcac68 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -118,8 +118,7 @@ static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index e54cce2b9175..cedc99184dad 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -110,9 +110,7 @@ static int inode_storage_delete(struct inode *inode, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index bcf7e7f42d18..5dcdf8e523b4 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -308,33 +308,6 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor return free_local_storage; } -static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, - bool reuse_now) -{ - struct bpf_local_storage *local_storage; - bool free_local_storage = false; - HLIST_HEAD(selem_free_list); - unsigned long flags; - - if (unlikely(!selem_linked_to_storage_lockless(selem))) - /* selem has already been unlinked from sk */ - return; - - local_storage = rcu_dereference_check(selem->local_storage, - bpf_rcu_lock_held()); - - raw_spin_lock_irqsave(&local_storage->lock, flags); - if (likely(selem_linked_to_storage(selem))) - free_local_storage = bpf_selem_unlink_storage_nolock( - local_storage, selem, &selem_free_list); - raw_spin_unlock_irqrestore(&local_storage->lock, flags); - - bpf_selem_free_list(&selem_free_list, reuse_now); - - if (free_local_storage) - bpf_local_storage_free(local_storage, reuse_now); -} - void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem) { @@ -387,19 +360,43 @@ static void bpf_selem_link_map_nolock(struct bpf_local_storage_map_bucket *b, hlist_add_head_rcu(&selem->map_node, &b->list); } -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) { - int err; + struct bpf_local_storage *local_storage; + bool free_local_storage = false; + HLIST_HEAD(selem_free_list); + unsigned long flags; + int err = 0; - /* Always unlink from map before unlinking from local_storage - * because selem will be freed after successfully unlinked from - * the local_storage. - */ - err = bpf_selem_unlink_map(selem); - if (err) - return; + if (unlikely(!selem_linked_to_storage_lockless(selem))) + /* selem has already been unlinked from sk */ + return 0; + + local_storage = rcu_dereference_check(selem->local_storage, + bpf_rcu_lock_held()); + + raw_spin_lock_irqsave(&local_storage->lock, flags); + if (likely(selem_linked_to_storage(selem))) { + /* Always unlink from map before unlinking from local_storage + * because selem will be freed after successfully unlinked from + * the local_storage. + */ + err = bpf_selem_unlink_map(selem); + if (err) + goto out; + + free_local_storage = bpf_selem_unlink_storage_nolock( + local_storage, selem, &selem_free_list); + } +out: + raw_spin_unlock_irqrestore(&local_storage->lock, flags); - bpf_selem_unlink_storage(selem, reuse_now); + bpf_selem_free_list(&selem_free_list, reuse_now); + + if (free_local_storage) + bpf_local_storage_free(local_storage, reuse_now); + + return err; } void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage, diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index a1dc1bf0848a..ab902364ac23 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -167,9 +167,7 @@ static int task_storage_delete(struct task_struct *task, struct bpf_map *map, if (!nobusy) return -EBUSY; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 0b85d8f2c17e..d7b5c4551997 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -40,9 +40,7 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } /* Called by __sk_destruct() & bpf_sk_storage_clone() */ -- 2.47.3