On Tue, Oct 27, 2020 at 06:03:13PM +0100, KP Singh wrote:
[ ... ]
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index e6ceac3f7d62..bb443c4f3637 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -157,6 +157,7 @@ enum bpf_map_type {
> BPF_MAP_TYPE_STRUCT_OPS,
> BPF_MAP_TYPE_RINGBUF,
> BPF_MAP_TYPE_INODE_STORAGE,
> + BPF_MAP_TYPE_TASK_STORAGE,
> };
>
> /* Note that tracing related programs such as
> @@ -3742,6 +3743,42 @@ union bpf_attr {
> * Return
> * The helper returns **TC_ACT_REDIRECT** on success or
> * **TC_ACT_SHOT** on error.
> + *
> + * void *bpf_task_storage_get(struct bpf_map *map, void *task, void *value,
> u64 flags)
After peeking patch 2, I think the pointer type should be
"struct task_struct *task" instead of "void *task".
Same for bpf_task_storage_delete().
> + * Description
> + * Get a bpf_local_storage from the *task*.
> + *
> + * Logically, it could be thought of as getting the value from
> + * a *map* with *task* as the **key**. From this
> + * perspective, the usage is not much different from
> + * **bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
> + * helper enforces the key must be an task_struct and the map must
> also
> + * be a **BPF_MAP_TYPE_TASK_STORAGE**.
> + *
> + * Underneath, the value is stored locally at *task* instead of
> + * the *map*. The *map* is used as the bpf-local-storage
> + * "type". The bpf-local-storage "type" (i.e. the *map*) is
> + * searched against all bpf_local_storage residing at *task*.
> + *
> + * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
> + * used such that a new bpf_local_storage will be
> + * created if one does not exist. *value* can be used
> + * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
> + * the initial value of a bpf_local_storage. If *value* is
> + * **NULL**, the new bpf_local_storage will be zero initialized.
> + * Return
> + * A bpf_local_storage pointer is returned on success.
> + *
> + * **NULL** if not found or there was an error in adding
> + * a new bpf_local_storage.
> + *
> + * int bpf_task_storage_delete(struct bpf_map *map, void *task)
> + * Description
> + * Delete a bpf_local_storage from a *task*.
> + * Return
> + * 0 on success.
> + *
> + * **-ENOENT** if the bpf_local_storage cannot be found.
> */
