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From: Pedro Tammela <pctammela@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>, Joe Stringer <joe@cilium.io>,
	Quentin Monnet <quentin@isovalent.com>,
	netdev@vger.kernel.org (open list:BPF (Safe dynamic programs and
	tools)),
	bpf@vger.kernel.org (open list:BPF (Safe dynamic programs and
	tools)), linux-kernel@vger.kernel.org (open list)
Cc: Pedro Tammela <pctammela@mojatatu.com>
Subject: [PATCH bpf-next] libbpf: clarify flags in ringbuf helpers
Date: Tue,  6 Apr 2021 15:58:04 -0300	[thread overview]
Message-ID: <20210406185806.377576-1-pctammela@mojatatu.com> (raw)

In 'bpf_ringbuf_reserve()' we require the flag to '0' at the moment.

For 'bpf_ringbuf_{discard,submit,output}' a flag of '0' might send a
notification to the process if needed.

Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
---
 include/uapi/linux/bpf.h       | 7 +++++++
 tools/include/uapi/linux/bpf.h | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 49371eba98ba..8c5c7a893b87 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4061,12 +4061,15 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
  * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
  * 	Description
  * 		Reserve *size* bytes of payload in a ring buffer *ringbuf*.
+ * 		*flags* must be 0.
  * 	Return
  * 		Valid pointer with *size* bytes of memory available; NULL,
  * 		otherwise.
@@ -4078,6 +4081,8 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		Nothing. Always succeeds.
  *
@@ -4088,6 +4093,8 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		Nothing. Always succeeds.
  *
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 69902603012c..51df1bd45cef 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4061,12 +4061,15 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		0 on success, or a negative error in case of failure.
  *
  * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
  * 	Description
  * 		Reserve *size* bytes of payload in a ring buffer *ringbuf*.
+ * 		*flags* must be 0.
  * 	Return
  * 		Valid pointer with *size* bytes of memory available; NULL,
  * 		otherwise.
@@ -4078,6 +4081,8 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		Nothing. Always succeeds.
  *
@@ -4088,6 +4093,8 @@ union bpf_attr {
  * 		of new data availability is sent.
  * 		If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
  * 		of new data availability is sent unconditionally.
+ * 		If **0** is specified in *flags*, notification
+ * 		of new data availability is sent if needed.
  * 	Return
  * 		Nothing. Always succeeds.
  *
-- 
2.25.1


             reply	other threads:[~2021-04-06 18:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 18:58 Pedro Tammela [this message]
2021-04-07 18:42 ` [PATCH bpf-next] libbpf: clarify flags in ringbuf helpers Joe Stringer
2021-04-07 19:58   ` Andrii Nakryiko
2021-04-07 20:10     ` Pedro Tammela
2021-04-07 21:16       ` Andrii Nakryiko

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