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authorQuentin Monnet <quentin.monnet@netronome.com>2019-03-14 12:38:39 +0000
committerAlexei Starovoitov <ast@kernel.org>2019-03-14 14:03:21 -0700
commit62369db2df8d1edfa040878203b446e023a16802 (patch)
tree2d35759b69b786fb7de6d41e14bc320a3595d88a
parentcd70182e8d530bf806176c529105c350d4d7fbd9 (diff)
bpf: fix documentation for eBPF helpers
Another round of minor fixes for the documentation of the BPF helpers located in the UAPI bpf.h header file. Changes include: - Moving around description of some helpers, to keep the descriptions in the same order as helpers are declared (bpf_map_push_elem(), leftover from commit 90b1023f68c7 ("bpf: fix documentation for eBPF helpers"), bpf_rc_keydown(), and bpf_skb_ancestor_cgroup_id()). - Fixing typos ("contex" -> "context"). - Harmonising return types ("void* " -> "void *", "uint64_t" -> "u64"). - Addition of the "bpf_" prefix to bpf_get_storage(). - Light additions of RST markup on some keywords. - Empty line deletion between description and return value for bpf_tcp_sock(). - Edit for the description for bpf_skb_ecn_set_ce() (capital letters, acronym expansion, no effect if ECT not set, more details on return value). Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--include/uapi/linux/bpf.h128
1 files changed, 65 insertions, 63 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 983b25cb608d..4465d00d3493 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -502,16 +502,6 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
- * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
- * Description
- * Push an element *value* in *map*. *flags* is one of:
- *
- * **BPF_EXIST**
- * If the queue/stack is full, the oldest element is removed to
- * make room for this.
- * Return
- * 0 on success, or a negative error in case of failure.
- *
* int bpf_probe_read(void *dst, u32 size, const void *src)
* Description
* For tracing programs, safely attempt to read *size* bytes from
@@ -1435,14 +1425,14 @@ union bpf_attr {
* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
- * *skb*, but gets socket from **struct bpf_sock_addr** contex.
+ * *skb*, but gets socket from **struct bpf_sock_addr** context.
* Return
* A 8-byte long non-decreasing number.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
- * *skb*, but gets socket from **struct bpf_sock_ops** contex.
+ * *skb*, but gets socket from **struct bpf_sock_ops** context.
* Return
* A 8-byte long non-decreasing number.
*
@@ -2098,52 +2088,52 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
- * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ * int bpf_rc_repeat(void *ctx)
* Description
* This helper is used in programs implementing IR decoding, to
- * report a successfully decoded key press with *scancode*,
- * *toggle* value in the given *protocol*. The scancode will be
- * translated to a keycode using the rc keymap, and reported as
- * an input key down event. After a period a key up event is
- * generated. This period can be extended by calling either
- * **bpf_rc_keydown**\ () again with the same values, or calling
- * **bpf_rc_repeat**\ ().
+ * report a successfully decoded repeat key message. This delays
+ * the generation of a key up event for previously generated
+ * key down event.
*
- * Some protocols include a toggle bit, in case the button was
- * released and pressed again between consecutive scancodes.
+ * Some IR protocols like NEC have a special IR message for
+ * repeating last button, for when a button is held down.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
- * The *protocol* is the decoded protocol number (see
- * **enum rc_proto** for some predefined values).
- *
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
- * int bpf_rc_repeat(void *ctx)
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
* Description
* This helper is used in programs implementing IR decoding, to
- * report a successfully decoded repeat key message. This delays
- * the generation of a key up event for previously generated
- * key down event.
+ * report a successfully decoded key press with *scancode*,
+ * *toggle* value in the given *protocol*. The scancode will be
+ * translated to a keycode using the rc keymap, and reported as
+ * an input key down event. After a period a key up event is
+ * generated. This period can be extended by calling either
+ * **bpf_rc_keydown**\ () again with the same values, or calling
+ * **bpf_rc_repeat**\ ().
*
- * Some IR protocols like NEC have a special IR message for
- * repeating last button, for when a button is held down.
+ * Some protocols include a toggle bit, in case the button was
+ * released and pressed again between consecutive scancodes.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
+ * The *protocol* is the decoded protocol number (see
+ * **enum rc_proto** for some predefined values).
+ *
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
- * uint64_t bpf_skb_cgroup_id(struct sk_buff *skb)
+ * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
* Description
* Return the cgroup v2 id of the socket associated with the *skb*.
* This is roughly similar to the **bpf_get_cgroup_classid**\ ()
@@ -2159,30 +2149,12 @@ union bpf_attr {
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
- * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
- * Description
- * Return id of cgroup v2 that is ancestor of cgroup associated
- * with the *skb* at the *ancestor_level*. The root cgroup is at
- * *ancestor_level* zero and each step down the hierarchy
- * increments the level. If *ancestor_level* == level of cgroup
- * associated with *skb*, then return value will be same as that
- * of **bpf_skb_cgroup_id**\ ().
- *
- * The helper is useful to implement policies based on cgroups
- * that are upper in hierarchy than immediate cgroup associated
- * with *skb*.
- *
- * The format of returned id and helper limitations are same as in
- * **bpf_skb_cgroup_id**\ ().
- * Return
- * The id is returned or 0 in case the id could not be retrieved.
- *
* u64 bpf_get_current_cgroup_id(void)
* Return
* A 64-bit integer containing the current cgroup id based
* on the cgroup within which the current task is running.
*
- * void* get_local_storage(void *map, u64 flags)
+ * void *bpf_get_local_storage(void *map, u64 flags)
* Description
* Get the pointer to the local storage area.
* The type and the size of the local storage is defined
@@ -2209,6 +2181,24 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
+ * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
+ * Description
+ * Return id of cgroup v2 that is ancestor of cgroup associated
+ * with the *skb* at the *ancestor_level*. The root cgroup is at
+ * *ancestor_level* zero and each step down the hierarchy
+ * increments the level. If *ancestor_level* == level of cgroup
+ * associated with *skb*, then return value will be same as that
+ * of **bpf_skb_cgroup_id**\ ().
+ *
+ * The helper is useful to implement policies based on cgroups
+ * that are upper in hierarchy than immediate cgroup associated
+ * with *skb*.
+ *
+ * The format of returned id and helper limitations are same as in
+ * **bpf_skb_cgroup_id**\ ().
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
* struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
@@ -2289,6 +2279,16 @@ union bpf_attr {
* Return
* 0 on success, or a negative error in case of failure.
*
+ * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
+ * Description
+ * Push an element *value* in *map*. *flags* is one of:
+ *
+ * **BPF_EXIST**
+ * If the queue/stack is full, the oldest element is
+ * removed to make room for this.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
* int bpf_map_pop_elem(struct bpf_map *map, void *value)
* Description
* Pop an element from *map*.
@@ -2346,33 +2346,35 @@ union bpf_attr {
* struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_sock** pointer such
- * that all the fields in bpf_sock can be accessed.
+ * that all the fields in this **bpf_sock** can be accessed.
* Return
- * A **struct bpf_sock** pointer on success, or NULL in
+ * A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_tcp_sock** pointer from a
* **struct bpf_sock** pointer.
- *
* Return
- * A **struct bpf_tcp_sock** pointer on success, or NULL in
+ * A **struct bpf_tcp_sock** pointer on success, or **NULL** in
* case of failure.
*
* int bpf_skb_ecn_set_ce(struct sk_buf *skb)
- * Description
- * Sets ECN of IP header to ce (congestion encountered) if
- * current value is ect (ECN capable). Works with IPv6 and IPv4.
- * Return
- * 1 if set, 0 if not set.
+ * Description
+ * Set ECN (Explicit Congestion Notification) field of IP header
+ * to **CE** (Congestion Encountered) if current value is **ECT**
+ * (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
+ * and IPv4.
+ * Return
+ * 1 if the **CE** flag is set (either by the current helper call
+ * or because it was already present), 0 if it is not set.
*
* struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
* Description
- * Return a **struct bpf_sock** pointer in TCP_LISTEN state.
- * bpf_sk_release() is unnecessary and not allowed.
+ * Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
+ * **bpf_sk_release**\ () is unnecessary and not allowed.
* Return
- * A **struct bpf_sock** pointer on success, or NULL in
+ * A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*/
#define __BPF_FUNC_MAPPER(FN) \