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Wed, 25 Sep 2024 22:30:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727303426; bh=p9xJJCK3sjdnEPQSrpwEL4Bd6PM0VmkqDDJfyawq95E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p1oejC7+XVCwNRAWMWb4liG+RlJRSHTe6i7jZnnI1bsrdWYUvIbiYRhAcYn7mK9A6 Rb6y1UTGncPTi2bKRvBzAX3S29OJmrzbFtf7uooMNt3kb1kihPEz63vK+n5Q/rDBa+ QiV/ajK12l2NTZoqyuuczq0zNb6+Hm1CM3Am1n8TZYMmCU3JaDoOzrhlsJmWKwJ3PY 6fGuKaZLfIj2SPcMsxEFeRfCgIHQ7G+lRIVWwVdQbmFZMdUw0X5UwV4Hpma8I9kJSa 4P+1U360/3PhTx5bYR5nlRI1rWBbeAE0K2/ODtT9NWqFl18NqTXV/QetfcyQSILH2I 9Z+4pLAf+dk3w== 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 Subject: [RFC/PATCH bpf-next 2/3] mm/bpf: Add bpf_get_slab_cache() kfunc Date: Wed, 25 Sep 2024 15:30:22 -0700 Message-ID: <20240925223023.735947-3-namhyung@kernel.org> X-Mailer: git-send-email 2.46.0.792.g87dc391469-goog In-Reply-To: <20240925223023.735947-1-namhyung@kernel.org> References: <20240925223023.735947-1-namhyung@kernel.org> MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 8E4D61C000B X-Stat-Signature: bsuyz4q6jztfcadhrc4nq4h7ze93xprt X-HE-Tag: 1727303427-280109 X-HE-Meta: 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 YQBptILo C9HOIk4NuDhXuMY0fJ/1u4H9CdXGrEPtgdVzb/wluughHvarLmPeNLKT0YJPDnUAXhyFpkGT8gLEjXdcAgSMsSH1C6SFkc5JpyPOXMHXcrCNFxPux0RZqFwgpW5QneLPVCkYUaKA4LrfJPuW6pX2ljaFFydvnczV3TkNfTECFy1frAL4ucTH37CX+hNTQA4FEX2HgFGbukazz3lGPfwnF+FlFmCFVVLbgVKivoMfQCxnWkSSNRNc49VbsRmJ8WO9QaRe/tCf8J+iFw2WaX6hoUMYcffOJ2pail2v0YvLHPVtvUflsYHq/fe6jEBdzDs0gtEQxwBrj/QRUu80tKZ0dak0NGcO2V6OESKjt X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The bpf_get_slab_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 Signed-off-by: Namhyung Kim --- kernel/bpf/helpers.c | 1 + mm/slab_common.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 1a43d06eab286c26..03db007a247175c4 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_slab_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..a87adcf182f49fc4 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1322,6 +1322,20 @@ size_t ksize(const void *objp) } EXPORT_SYMBOL(ksize); +#ifdef CONFIG_BPF_SYSCALL +__bpf_kfunc_start_defs(); + +__bpf_kfunc struct kmem_cache *bpf_get_slab_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);