On 11/3/22 3:18 PM, Kumar Kartikeya Dwivedi wrote:
On Thu, Nov 03, 2022 at 12:51:13PM IST, Yonghong Song wrote:Add bpf_rcu_read_lock() and bpf_rcu_read_unlock() helpers. Both helpers are available to all program types with CAP_BPF capability. Signed-off-by: Yonghong Song <yhs@xxxxxx> --- include/linux/bpf.h | 2 ++ include/uapi/linux/bpf.h | 14 ++++++++++++++ kernel/bpf/core.c | 2 ++ kernel/bpf/helpers.c | 26 ++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 14 ++++++++++++++ 5 files changed, 58 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8d948bfcb984..a9bda4c91fc7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2554,6 +2554,8 @@ extern const struct bpf_func_proto bpf_get_retval_proto; extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto; extern const struct bpf_func_proto bpf_cgrp_storage_get_proto; extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto; +extern const struct bpf_func_proto bpf_rcu_read_lock_proto; +extern const struct bpf_func_proto bpf_rcu_read_unlock_proto; const struct bpf_func_proto *tracing_prog_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 94659f6b3395..e86389cd6133 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5481,6 +5481,18 @@ union bpf_attr { * 0 on success. * * **-ENOENT** if the bpf_local_storage cannot be found. + * + * void bpf_rcu_read_lock(void) + * Description + * Call kernel rcu_read_lock(). + * Return + * None. + * + * void bpf_rcu_read_unlock(void) + * Description + * Call kernel rcu_read_unlock(). + * Return + * None. */It would be better to not bake these into UAPI and keep them unstable only IMO.
rcu_read_lock/unlock() are well known in kernel programming. I think put them as stable UAPI should be fine. But I will reword the description to remove any direct reference to kernel functions.
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