From nobody Sat Feb 7 06:14:52 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0AD57254841; Tue, 29 Jul 2025 10:28:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753784931; cv=none; b=i2j4SIEG6Es/tMnarx9NQBlnGMFIBiC0x2Bc3E76vh3LR0V7P6l10trecYKUApeWCaG/NiPSnZ6AtmAi9Chp0l90+mDOV6oA1aUv1wtlNni41qe1ot8ytjD91d5RUA32ty2wnqckfjUIxeS0LUbCtjh5HZ3QufWscS2xvUQqCBI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753784931; c=relaxed/simple; bh=h3k3dbcXrYPALSttNREnJ435oHCZsHpXZ8zQdyx2QEQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S27suGYM/EJIwRbU54JNLwy6cmP8aKPgWyf9enwtLI2W/b/4xDoI6oRX8qMEtuggMuvLyMWQ9kU5SatIvt4WupVSz+SlmbdrgS4jta57+6KKut106xSckj8Dp9e9p1vQXqX8E4nQCCRS8NHBFbH+fI85S2z5BIWkTQSuuVelvU8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OYpdw+Ph; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OYpdw+Ph" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A33DEC4CEEF; Tue, 29 Jul 2025 10:28:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753784930; bh=h3k3dbcXrYPALSttNREnJ435oHCZsHpXZ8zQdyx2QEQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OYpdw+Ph67FkPffntdOi6PrnWlZxh4yCTGTMToqQPOHc4at6u6XbgCY+XOEiDkG2d IEW+R6cUKYMvkfs2s0C67Bjyfs73V6KFcr4s0IaAEQQJC54oELWuzApH3QeFdblp+w FRM+DxOAN9N+uxe9r9IauULWkUxkuNBygGWqwuoXipP58cqIbF4z8vhMEPq1NWnsn+ cPrR6M88PkrfcdeA3nZj4kEglWi9ueQq4jnUCf+206U9BBNq0Xl+biu4B88p9kWfIO pnx/SfOorAG02aZj6Ai1ZC+/aBcDQ+Mkvv2TckMf9tIHtrSH74Dec5u8egU4t/cmOS lMr0e+E57ic7A== From: Jiri Olsa To: Steven Rostedt , Florent Revest , Mark Rutland Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Menglong Dong Subject: [RFC 03/10] ftrace: Add unregister_ftrace_direct_hash function Date: Tue, 29 Jul 2025 12:28:06 +0200 Message-ID: <20250729102813.1531457-4-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250729102813.1531457-1-jolsa@kernel.org> References: <20250729102813.1531457-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Adding unregister_ftrace_direct_hash function that unregisters all entries (ip -> direct) provided in hash argument. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call unregister_ftrace_direct_hash multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 +++ kernel/trace/ftrace.c | 98 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 104 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index e45bcc9de53b..7ff6004498c0 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -527,6 +527,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsign= ed long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr= ); =20 int register_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_hash= *hash); +int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_ha= sh *hash); =20 void ftrace_stub_direct_tramp(void); =20 @@ -559,6 +560,11 @@ int register_ftrace_direct_hash(struct ftrace_ops *ops= , struct ftrace_hash *hash return -ENODEV; } =20 +int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_ha= sh *hash) +{ + return -ENODEV; +} + /* * This must be implemented by the architecture. * It is the way the ftrace direct_ops helper, when called diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1dbb113f4e9c..d761237ec70f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6342,6 +6342,104 @@ int register_ftrace_direct_hash(struct ftrace_ops *= ops, struct ftrace_hash *hash } EXPORT_SYMBOL_GPL(register_ftrace_direct_hash); =20 +/** + * hash_sub - substracts @b from @a and returns the result + * @a: struct ftrace_hash object + * @b: struct ftrace_hash object + * + * Returns struct ftrace_hash object on success, NULL on error. + */ +static struct ftrace_hash *hash_sub(struct ftrace_hash *a, struct ftrace_h= ash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size, i; + + sub =3D alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + goto error; + + size =3D 1 << b->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) + goto error; + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; + + error: + free_ftrace_hash(sub); + return NULL; +} + +int unregister_ftrace_direct_hash(struct ftrace_ops *ops, struct ftrace_ha= sh *hash) +{ + struct ftrace_hash *new_hash =3D NULL, *filter_hash =3D NULL, *free_hash = =3D NULL; + struct ftrace_func_entry *del, *entry; + unsigned long size, i; + int err =3D -EINVAL; + + if (!hash_count(hash)) + return 0; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions =3D=3D EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + /* Make sure requested entries are already registered. */ + size =3D 1 << hash->size_bits; + for (i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct !=3D entry->direct) + goto out_unlock; + } + } + + filter_hash =3D hash_sub(ops->func_hash->filter_hash, hash); + if (!filter_hash) + goto out_unlock; + + new_hash =3D hash_sub(direct_functions, hash); + if (!new_hash) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(filter_hash)) { + err =3D unregister_ftrace_function(ops); + /* cleanup for possible another register call */ + ops->func =3D NULL; + ops->trampoline =3D 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash =3D NULL; + } else { + err =3D ftrace_update_ops(ops, filter_hash, EMPTY_HASH); + } + + free_hash =3D direct_functions; + rcu_assign_pointer(direct_functions, new_hash); + + out_unlock: + mutex_unlock(&direct_mutex); + + if (free_hash && free_hash !=3D EMPTY_HASH) + call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb); + + if (filter_hash) + free_ftrace_hash(filter_hash); + + return err; +} +EXPORT_SYMBOL_GPL(unregister_ftrace_direct_hash); + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ =20 /** --=20 2.50.1