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([140.174.215.88]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c3e5511c63sm253828585a.113.2025.03.07.07.38.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Mar 2025 07:38:52 -0800 (PST) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, yonghong.song@linux.dev, tj@kernel.org, memxor@gmail.com, houtao@huaweicloud.com, Emil Tsalapatis , Hou Tao Subject: [PATCH v6 1/4] bpf: add kfunc for populating cpumask bits Date: Fri, 7 Mar 2025 10:38:44 -0500 Message-ID: <20250307153847.8530-2-emil@etsalapatis.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250307153847.8530-1-emil@etsalapatis.com> References: <20250307153847.8530-1-emil@etsalapatis.com> 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 Add a helper kfunc that sets the bitmap of a bpf_cpumask from BPF memory. Signed-off-by: Emil Tsalapatis (Meta) Acked-by: Hou Tao --- kernel/bpf/cpumask.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index cfa1c18e3a48..77900cbbbd75 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -420,6 +420,38 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask) return cpumask_weight(cpumask); } +/** + * bpf_cpumask_populate() - Populate the CPU mask from the contents of + * a BPF memory region. + * + * @cpumask: The cpumask being populated. + * @src: The BPF memory holding the bit pattern. + * @src__sz: Length of the BPF memory region in bytes. + * + * Return: + * * 0 if the struct cpumask * instance was populated successfully. + * * -EACCES if the memory region is too small to populate the cpumask. + * * -EINVAL if the memory region is not aligned to the size of a long + * and the architecture does not support efficient unaligned accesses. + */ +__bpf_kfunc int bpf_cpumask_populate(struct cpumask *cpumask, void *src, size_t src__sz) +{ + unsigned long source = (unsigned long)src; + + /* The memory region must be large enough to populate the entire CPU mask. */ + if (src__sz < bitmap_size(nr_cpu_ids)) + return -EACCES; + + /* If avoiding unaligned accesses, the input region must be aligned to the nearest long. */ + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && + !IS_ALIGNED(source, sizeof(long))) + return -EINVAL; + + bitmap_copy(cpumask_bits(cpumask), src, nr_cpu_ids); + + return 0; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(cpumask_kfunc_btf_ids) @@ -448,6 +480,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_any_and_distribute, KF_RCU) BTF_ID_FLAGS(func, bpf_cpumask_weight, KF_RCU) +BTF_ID_FLAGS(func, bpf_cpumask_populate, KF_RCU) BTF_KFUNCS_END(cpumask_kfunc_btf_ids) static const struct btf_kfunc_id_set cpumask_kfunc_set = {