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 <[email protected]>
---
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
+ * *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
--
2.34.1