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b=hJA3AxsKt5vguBDGX9K7MIPGuu6SdGytFc3+3mRtIJSZaC0iflWEZMUYifhPEinA+ k2L3ChKbEJfdVs4PX/54/LxfS0fcDnorfR0PgdCuhmw6EfqOFVIQ7Lv0s2DPGzZ1K9 exLNC31Bs8egNfzQuiFyMQhIhXPHq7oKaFRL1p6XhHLzRyixitlCbGSknGCQbvT+9u Pi5GiuRIEPIMzsDOHP7leaZFfZLU0/x/gchgF/VZtway62LW5UM2jlFIMkoQAvbZHc I5kYDS96HN0rG0eRx1NdNmfJL4aS4Yhs2jV3bsX5Jsor/9kkYYjIVhFphgAlpd+JJS gmbcVFlVFkbKQ== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi Cc: Peter Zijlstra , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andrew Morton , David Hildenbrand , Mike Rapoport , Emil Tsalapatis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 4/8] bpf: Add bpf_struct_ops_for_each_prog() Date: Fri, 22 May 2026 07:22:15 -1000 Message-ID: <20260522172219.1423324-5-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260522172219.1423324-1-tj@kernel.org> References: <20260522172219.1423324-1-tj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: akmrwzzms9rgo8ho9bquoy5fek5jwjcy X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 091F21C0006 X-HE-Tag: 1779470544-822842 X-HE-Meta: U2FsdGVkX1+jxcIGwLtg8xb0eyNzVEtJeFJqCoLXRaSJbN7NLslThgf/Qq0svRwM3nQ1RngMG+9zwgmuIQTgFpC94edJBgr4vInwYQZMBP+EO2fIWQz36oPzC86K6r/TstbXrfhCLzGkJ2q6HYLY7HSYm5kEsqWyOtvD0g70W5tIalbt1xL+uZrmYutBTwozJkV4ngmoLMKeFgx8j1lR0e0yDdG7do75bOjOD40SH23dQ5ofDlSmyT/A2135ngMkgM7+rPLM3CSsUGDKP4LRVvC9FtONCIPZxINyzvSF8FjOa97TdTiKMVsytiJdwD7pUsvR71G57m7ZQdkn0CS1Sk3Q6pVfbDdNQai6U+5h0QKWj5OKRQzmu5pn5XcMRppOCPRAGewvQsSNCpKNvJI716sfCkZ5SLr+vnY/eYj1/W0kDkA04gfQElTTvU3tVF6blGSODR5eXW1Ch3doXWZvn5ujJMVVJVdlF6z3LUd4zgVJ83zhmqg6FfX6yXNp0bPwalstwVnIl48YUaxBg+t3DrgTpIdIqPwjQeFlsTi2VkuKigZlr+az65b7elbYLmiGIKx/+HMv08N+yzrkjJ0Og3+YqQ4jfJsYo8Aa1sZYY2Ld61Xz4mHDqc7CI9DnYVN0zXPgV53rGFLgbuxwmr/yCTWcVCLAyOOueDql33JuE3i1+Hl7mrBVPQv36NuUDk6z4g9/RPA3qSyjnnMZcSkRKpjKHPSQdU3STnZE8uYszfQFT472g7APaes+94X2EPZBFRTAdbOzoXsYQeaNURu51J28q/tyJC0BG4qTkN+LoabnzUTHUDsiZ7ZgDbBQRYv3fo3NL8Tn4ByIZMfYp0YdUhCkfHrn/XE8sc+2megbdQ95AvsWOP+b0okIo0m5X5u1dcwrqJs8zBAyAIugPEgO2K8AMq9akrRLjN8aT5QnCXEVjrdYHM+Xd8YmJbOrOF16WvUlbOtwfUOQS9krkD/ URw/RHWX ftvzPR/rH/qdshjkkLhCqnhJL0526cQteQCPnMcFWOHrsQD1k9fb66HNTJb+L4vWQ1ewhwvXMdbkGmpugXVifaMOo+H22qh6MEdJX0hQW131kgLnY60Obqqf7CxSrfg35/7I5b1oTMsRy4fbZyptpKaN1JsVMB7YA3ZyWt9q3Zi1KM92N6vc/Eltkvq/2u7PKTBzNx3TlX+T8juZImQq81O8jEZp5PhBZW3+jdV2sscz68ordOls7YidRsHd8P+b/JIwpacaT9O5O6KNg7v7jRVp6oVcDcN88kfRqB46bxolsClKh/MQ57bTmbF8FxsdX1HR2Qk/5dKD+EMu+HbklQe7LZQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add a helper that walks the member progs of the struct_ops map containing a given @kdata vmtable. struct_ops ->reg() callbacks (and similar) sometimes need to inspect the loaded BPF programs, e.g. to discover maps they reference via prog->aux->used_maps. The implementation mirrors bpf_struct_ops_id(): container_of @kdata to recover the bpf_struct_ops_map, then iterate st_map->links[i]->prog for i in [0, funcs_cnt). Same access pattern, no new locking - by the time ->reg() fires st_map is fully populated and stable. A sched_ext follow-up walks the member progs of a cid-form scheduler's struct_ops map, reads prog->aux->arena directly, and requires all member progs to reference exactly one arena, without requiring the BPF program to call a registration kfunc. Signed-off-by: Tejun Heo Reviewed-by: Emil Tsalapatis --- include/linux/bpf.h | 3 +++ kernel/bpf/bpf_struct_ops.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 64968ca6db51..5b99d786e98c 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2129,6 +2129,9 @@ int bpf_prog_assoc_struct_ops(struct bpf_prog *prog, struct bpf_map *map); void bpf_prog_disassoc_struct_ops(struct bpf_prog *prog); void *bpf_prog_get_assoc_struct_ops(const struct bpf_prog_aux *aux); u32 bpf_struct_ops_id(const void *kdata); +int bpf_struct_ops_for_each_prog(const void *kdata, + int (*cb)(struct bpf_prog *prog, void *data), + void *data); #ifdef CONFIG_NET /* Define it here to avoid the use of forward declaration */ diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 05b366b821c3..16aec18ed31b 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -1203,6 +1203,42 @@ u32 bpf_struct_ops_id(const void *kdata) } EXPORT_SYMBOL_GPL(bpf_struct_ops_id); +/** + * bpf_struct_ops_for_each_prog - Invoke @cb for each member prog + * @kdata: kernel-side struct_ops vmtable (the @kdata arg to ->reg/->update/->unreg) + * @cb: callback invoked once per member prog; non-zero return stops iteration + * @data: opaque argument passed to @cb + * + * Walks the struct_ops member progs registered on the map containing @kdata. + * Intended for use from struct_ops ->reg() callbacks (and similar) that need to + * inspect the loaded BPF programs (for example to discover maps they reference + * via @prog->aux->used_maps). + * + * Return 0 if iteration completed, otherwise the first non-zero @cb return. + */ +int bpf_struct_ops_for_each_prog(const void *kdata, + int (*cb)(struct bpf_prog *prog, void *data), + void *data) +{ + struct bpf_struct_ops_value *kvalue; + struct bpf_struct_ops_map *st_map; + u32 i; + int ret; + + kvalue = container_of(kdata, struct bpf_struct_ops_value, data); + st_map = container_of(kvalue, struct bpf_struct_ops_map, kvalue); + + for (i = 0; i < st_map->funcs_cnt; i++) { + if (!st_map->links[i]) + continue; + ret = cb(st_map->links[i]->prog, data); + if (ret) + return ret; + } + return 0; +} +EXPORT_SYMBOL_GPL(bpf_struct_ops_for_each_prog); + static bool bpf_struct_ops_valid_to_reg(struct bpf_map *map) { struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map; -- 2.54.0