Hi,
On 7/17/2023 7:43 PM, Anton Protopopov wrote:
> The map_lookup{,_and_delete}_batch operations return same values. Make
> this clear in documentation. Also, update the comments so that this is
> more clear that -ENOENT is a valid return value in case of success. (In
> fact, this is the most common return value, as this is reasonable to do
> map_lookup_batch(MAX_ENTRIES), which, in case of success, will always
> return -ENOENT.)
>
> Signed-off-by: Anton Protopopov <aspsk@xxxxxxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 600d0caebbd8..9e6e277bedab 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -632,17 +632,19 @@ union bpf_iter_link_info {
> * returning the lock. This must be specified if the
> * elements contain a spinlock.
> *
> - * On success, *count* elements from the map are copied into the
> - * user buffer, with the keys copied into *keys* and the values
> - * copied into the corresponding indices in *values*.
> - *
> - * If an error is returned and *errno* is not **EFAULT**, *count*
> - * is set to the number of successfully processed elements.
> + * On success, up to *count* elements from the map are copied into
> + * the user buffer, with the keys copied into *keys* and the
> + * values copied into the corresponding indices in *values*.
> *
> * Return
> * Returns zero on success. On error, -1 is returned and *errno*
> * is set appropriately.
> *
> + * If an error is returned and *errno* is not **EFAULT**, then
Maybe we should say "is not EFAULT or EINVAL" ? Otherwise, the update
looks good to me, so
Acked-by: Hou Tao <houtao1@xxxxxxxxxx>
> + * *count* is set to the number of successfully processed
> + * elements. In particular, the *errno* may be set to **ENOENT**
> + * in case of success to indicate that the end of map is reached.
> + *
> * May set *errno* to **ENOSPC** to indicate that *keys* or
> * *values* is too small to dump an entire bucket during
> * iteration of a hash-based map type.
> @@ -655,15 +657,15 @@ union bpf_iter_link_info {
> * **BPF_MAP_LOOKUP_BATCH** with two exceptions:
> *
> * * Every element that is successfully returned is also deleted
> - * from the map. This is at least *count* elements. Note that
> - * *count* is both an input and an output parameter.
> + * from the map. The *count* parameter is set to the number of
> + * returned elements. This value can be less than the actual
> + * number of deleted elements, see the next item.
> * * Upon returning with *errno* set to **EFAULT**, up to
> * *count* elements may be deleted without returning the keys
> * and values of the deleted elements.
> *
> * Return
> - * Returns zero on success. On error, -1 is returned and *errno*
> - * is set appropriately.
> + * Same as the BPF_MAP_LOOKUP_BATCH return values.
> *
> * BPF_MAP_UPDATE_BATCH
> * Description
