From: Gyutae Bae <gyutae.opensource@navercorp.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org
Cc: John Fastabend <john.fastabend@gmail.com>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Minsu Jeon <minsu.jeon@navercorp.com>,
Siwan Kim <siwan.kim@navercorp.com>,
Jonghyeon Kim <jong-hyeon.kim@navercorp.com>,
Gyutae Bae <gyutae.bae@navercorp.com>
Subject: [RFC bpf-next 1/3] bpf: add BPF_F_COMPARE flag and compare fields to map elem UAPI
Date: Mon, 22 Jun 2026 16:16:47 +0900 [thread overview]
Message-ID: <20260622071649.31541-2-gyutae.opensource@navercorp.com> (raw)
In-Reply-To: <20260622071649.31541-1-gyutae.opensource@navercorp.com>
From: Gyutae Bae <gyutae.bae@navercorp.com>
Introduce the UAPI surface for a compare-and-delete primitive: a new map
flag BPF_F_COMPARE plus compare/compare_offset/compare_size fields let
a delete request name an expected value region. Behaviour is wired up in
the following patch; this adds the flag and fields (kernel + tools/ copy)
only.
Co-developed-by: Minsu Jeon <minsu.jeon@navercorp.com>
Signed-off-by: Minsu Jeon <minsu.jeon@navercorp.com>
Co-developed-by: Siwan Kim <siwan.kim@navercorp.com>
Signed-off-by: Siwan Kim <siwan.kim@navercorp.com>
Co-developed-by: Jonghyeon Kim <jong-hyeon.kim@navercorp.com>
Signed-off-by: Jonghyeon Kim <jong-hyeon.kim@navercorp.com>
Signed-off-by: Gyutae Bae <gyutae.bae@navercorp.com>
---
include/uapi/linux/bpf.h | 6 +++++-
tools/include/uapi/linux/bpf.h | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 89b36de5fdbb..4705b02fb6a4 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1397,7 +1397,7 @@ enum bpf_addr_space_cast {
BPF_ADDR_SPACE_CAST = 1,
};
-/* flags for BPF_MAP_UPDATE_ELEM command */
+/* flags for BPF_MAP_UPDATE_ELEM / BPF_MAP_DELETE_ELEM commands */
enum {
BPF_ANY = 0, /* create new element or update existing */
BPF_NOEXIST = 1, /* create new element if it didn't exist */
@@ -1405,6 +1405,7 @@ enum {
BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */
BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */
BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */
+ BPF_F_COMPARE = 32, /* compare-and-delete: delete elem only if value region == compare */
};
/* flags for BPF_MAP_CREATE command */
@@ -1586,6 +1587,9 @@ union bpf_attr {
__aligned_u64 next_key;
};
__u64 flags;
+ __aligned_u64 compare; /* user ptr to expected bytes (BPF_F_COMPARE) */
+ __u32 compare_offset; /* start offset within value */
+ __u32 compare_size; /* bytes to compare; 0 == whole value */
};
struct { /* struct used by BPF_MAP_*_BATCH commands */
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 89b36de5fdbb..4705b02fb6a4 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1397,7 +1397,7 @@ enum bpf_addr_space_cast {
BPF_ADDR_SPACE_CAST = 1,
};
-/* flags for BPF_MAP_UPDATE_ELEM command */
+/* flags for BPF_MAP_UPDATE_ELEM / BPF_MAP_DELETE_ELEM commands */
enum {
BPF_ANY = 0, /* create new element or update existing */
BPF_NOEXIST = 1, /* create new element if it didn't exist */
@@ -1405,6 +1405,7 @@ enum {
BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */
BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */
BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */
+ BPF_F_COMPARE = 32, /* compare-and-delete: delete elem only if value region == compare */
};
/* flags for BPF_MAP_CREATE command */
@@ -1586,6 +1587,9 @@ union bpf_attr {
__aligned_u64 next_key;
};
__u64 flags;
+ __aligned_u64 compare; /* user ptr to expected bytes (BPF_F_COMPARE) */
+ __u32 compare_offset; /* start offset within value */
+ __u32 compare_size; /* bytes to compare; 0 == whole value */
};
struct { /* struct used by BPF_MAP_*_BATCH commands */
--
2.39.5 (Apple Git-154)
next prev parent reply other threads:[~2026-06-22 7:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-22 7:16 [RFC bpf-next 0/3] bpf: compare-and-delete (BPF_F_COMPARE) for hash maps Gyutae Bae
2026-06-22 7:16 ` Gyutae Bae [this message]
2026-06-22 7:16 ` [RFC bpf-next 2/3] bpf: implement compare-and-delete (BPF_F_COMPARE) for BPF_MAP_TYPE_HASH Gyutae Bae
2026-06-22 7:16 ` [RFC bpf-next 3/3] selftests/bpf: test BPF_F_COMPARE compare-and-delete Gyutae Bae
2026-06-22 22:32 ` [RFC bpf-next 0/3] bpf: compare-and-delete (BPF_F_COMPARE) for hash maps Alexei Starovoitov
2026-06-23 2:58 ` Gyutae Bae
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