From patchwork Fri Sep 27 18:41:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13814481 X-Patchwork-Delegate: bpf@iogearbox.net 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 39B2C1C231E; Fri, 27 Sep 2024 18:41:37 +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=1727462498; cv=none; b=KMJZ9GijPBKkDPrSi5tOeIx3NGaTVlewlyc0uxXgYwCz2j1Mvfh5vi9kOZovfuhnRlc56D57tO7refLDtieH8/PjhAnQ24oGLdagOP8ZWt2tAG7Tt8sRQLi4JNOsl9tfRFMYkgQfDqD5v+W6FBP+c9rIc+k27w1u034T3AR1mFQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727462498; c=relaxed/simple; bh=aGXxmsEp/uzql1BOkNU+QldkkvWzmazSesv6pu9JlCg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QfD7fl0xB4Yzg7c/tt9MWoet5EfTJE6mfYdfOoNpBNHS3WxaeBy0xuzVa1uZXT6Z/6MkyRxiQB7i8RgYhZqYKWTR79R7Df+5UeLAqtJilxOEJwvWHBx2UM/MSxtBDt3FoQB4/ROcNpVzZ96HgUMwxkQN/FzNTUDxEo3k3x2oH3s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=h/xmwgNC; 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="h/xmwgNC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1612C4CED9; Fri, 27 Sep 2024 18:41:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727462497; bh=aGXxmsEp/uzql1BOkNU+QldkkvWzmazSesv6pu9JlCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h/xmwgNC9gCQMLx3EopU51gjZjDEszjSx7m0YzwM9dxl9jGiQIfZfu7fXfcf2beZz d/SmetuGMSmmNIkLuEdEl53xnFkV5+JkvmJD79VTWBih+Z720cMEeOFnbFQ21+Gb5M ZbMqLldLREXQzUUeKjYRGs5aEqw86o+UBP2TIqbLSO80yAV65emdDN7Tiy3gkHXRcP fRxziCdTpjXwWpzBaEGpvJiZt+d5v3MoGa6drDAMezJzaQg9D8YiepRoq7StCxX3ZO +2ATJyOcO4sK/7+bL5IhOebBEP3qkQwwSS7I8sIMgi9HAlDmMxpDg5ZdIRXCzsrOEi pYWhKpTE5LbEA== From: Namhyung Kim To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , LKML , bpf@vger.kernel.org, Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, Arnaldo Carvalho de Melo Subject: [RFC/PATCH bpf-next 2/3] mm/bpf: Add bpf_get_kmem_cache() kfunc Date: Fri, 27 Sep 2024 11:41:32 -0700 Message-ID: <20240927184133.968283-3-namhyung@kernel.org> X-Mailer: git-send-email 2.46.1.824.gd892dcdcdd-goog In-Reply-To: <20240927184133.968283-1-namhyung@kernel.org> References: <20240927184133.968283-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC The bpf_get_kmem_cache() is to get a slab cache information from a virtual address like virt_to_cache(). If the address is a pointer to a slab object, it'd return a valid kmem_cache pointer, otherwise NULL is returned. It doesn't grab a reference count of the kmem_cache so the caller is responsible to manage the access. The intended use case for now is to symbolize locks in slab objects from the lock contention tracepoints. Suggested-by: Vlastimil Babka Acked-by: Roman Gushchin (mm/*) Acked-by: Vlastimil Babka #mm/slab Signed-off-by: Namhyung Kim --- kernel/bpf/helpers.c | 1 + mm/slab_common.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 1a43d06eab286c26..bbc5800ec3afc899 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3090,6 +3090,7 @@ BTF_ID_FLAGS(func, bpf_iter_bits_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_bits_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_bits_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_copy_from_user_str, KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_get_kmem_cache, KF_RET_NULL) BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/mm/slab_common.c b/mm/slab_common.c index 7443244656150325..e648b05a635b94bf 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1322,6 +1322,22 @@ size_t ksize(const void *objp) } EXPORT_SYMBOL(ksize); +#ifdef CONFIG_BPF_SYSCALL +#include + +__bpf_kfunc_start_defs(); + +__bpf_kfunc struct kmem_cache *bpf_get_kmem_cache(u64 addr) +{ + struct slab *slab; + + slab = virt_to_slab((void *)(long)addr); + return slab ? slab->slab_cache : NULL; +} + +__bpf_kfunc_end_defs(); +#endif /* CONFIG_BPF_SYSCALL */ + /* Tracepoints definitions. */ EXPORT_TRACEPOINT_SYMBOL(kmalloc); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);