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Fri, 05 Sep 2025 09:45:18 -0700 (PDT) Received: from localhost ([2a01:4b00:bd1f:f500:e85d:a828:282d:d5c7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45ddc315d78sm7181295e9.4.2025.09.05.09.45.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Sep 2025 09:45:18 -0700 (PDT) From: Mykyta Yatsenko To: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, kafai@meta.com, kernel-team@meta.com, eddyz87@gmail.com, memxor@gmail.com Cc: Mykyta Yatsenko Subject: [PATCH bpf-next v3 5/7] bpf: extract map key pointer calculation Date: Fri, 5 Sep 2025 17:45:03 +0100 Message-ID: <20250905164508.1489482-6-mykyta.yatsenko5@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250905164508.1489482-1-mykyta.yatsenko5@gmail.com> References: <20250905164508.1489482-1-mykyta.yatsenko5@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mykyta Yatsenko Calculation of the BPF map key, given the pointer to a value is duplicated in a couple of places in helpers already, in the next patch another use case is introduced as well. This patch extracts that functionality into a separate function. Signed-off-by: Mykyta Yatsenko Acked-by: Kumar Kartikeya Dwivedi --- kernel/bpf/helpers.c | 31 ++++++++++++++----------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 89a5d8808ce8..109cb249e88c 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1081,6 +1081,18 @@ const struct bpf_func_proto bpf_snprintf_proto = { .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; +static void *map_key_from_value(struct bpf_map *map, void *value, u32 *arr_idx) +{ + if (map->map_type == BPF_MAP_TYPE_ARRAY) { + struct bpf_array *array = container_of(map, struct bpf_array, map); + + *arr_idx = ((char *)value - array->value) / array->elem_size; + return arr_idx; + } + BUG_ON(map->map_type != BPF_MAP_TYPE_HASH && map->map_type != BPF_MAP_TYPE_LRU_HASH); + return (void *)value - round_up(map->key_size, 8); +} + struct bpf_async_cb { struct bpf_map *map; struct bpf_prog *prog; @@ -1163,15 +1175,8 @@ static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer) * bpf_map_delete_elem() on the same timer. */ this_cpu_write(hrtimer_running, t); - if (map->map_type == BPF_MAP_TYPE_ARRAY) { - struct bpf_array *array = container_of(map, struct bpf_array, map); - /* compute the key */ - idx = ((char *)value - array->value) / array->elem_size; - key = &idx; - } else { /* hash or lru */ - key = value - round_up(map->key_size, 8); - } + key = map_key_from_value(map, value, &idx); callback_fn((u64)(long)map, (u64)(long)key, (u64)(long)value, 0, 0); /* The verifier checked that return value is zero. */ @@ -1197,15 +1202,7 @@ static void bpf_wq_work(struct work_struct *work) if (!callback_fn) return; - if (map->map_type == BPF_MAP_TYPE_ARRAY) { - struct bpf_array *array = container_of(map, struct bpf_array, map); - - /* compute the key */ - idx = ((char *)value - array->value) / array->elem_size; - key = &idx; - } else { /* hash or lru */ - key = value - round_up(map->key_size, 8); - } + key = map_key_from_value(map, value, &idx); rcu_read_lock_trace(); migrate_disable(); -- 2.51.0