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b=APzU+iQv4rh0acB52YSaIyInFGYquGdEFeHHg3Fl9plQlL7b7DbLT+9iJfSaFsLcx MkmbH9ysihwjXG9bUD1tTnDPczpxmmhKRbNEU0fDa3OcDDPhVzxSUohYpXiDJhAdo4 7WfnC7nLPVEt2oHSckKZRJFvHnoqdCw3llehZ7zK4wnPubZuOnW/3UZDe46a0Nn/Vb x0C57aQKa2p/VbfZEu01bvgSVUCCwQvIb6tfiYimIML+VtIeGozykQeicAk1xDrEV0 uvgLtPjdtbNZ7J5c02Neqnf+iayG22GobtiwFjl1JbKJKk6uEIWNUYLuPOgGnoXdse W+asDJLa6Of8g== 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: Wed, 20 May 2026 13:50:48 -1000 Message-ID: <20260520235052.4180316-5-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520235052.4180316-1-tj@kernel.org> References: <20260520235052.4180316-1-tj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 319BA1C000A X-Stat-Signature: d39wa3nfrpmf7kp589q57xx6g79ojf9m X-HE-Tag: 1779321058-906126 X-HE-Meta: U2FsdGVkX19LIyeoRICHFnAOD8lnnjb5JYKFZ/PFsBWz0ksIAZ8n5iy5zg5TVIWerk7+IBRtlCkH97FU0moDjgE8DljgoN2bZ9fuC7WLWFKAT4sgA3s8IIH2FdP2opf2td+ZYptekJHzvhVhDYNm8C3eRTFil9Y3vKxNrhxFihyCBsJchXPiGqv7BnDmn8wUley0AV5kfHowCdqfzWvmIxEM8v8yo7E7uI/h4asMeGisFCy4bDRQt4H2LW+5Y6UpjyeKUXrnMV4FY44uYmEPosXTuNKPI7CvlaZBn2to/hGMkA4M9pa3lrVZPO9YzYlHUevxjTeGHOejIMGaRtZElNpU9iTcwN01UgtFEjb6Lf6Wvqd6e42fMno+yCdA3GKXRgsf5sqHGTGtQzeSEGZLN6xn1TS+D+wrKckL9DO9hf2IHpbvpC0uym73wCtzaFE4xOrFIQGVTgX1pr72tAbSom7yXQktDrBY/ptGlNNj6hjBKT5Nqp5JOjaUWBoc8wQx5OqGXpG7q2rHMp2amcZIoA9iRAySJ4pJvXRiikbMEDFpWtWlnd4trepXDagucDlxUJSz+XHFdAVKPrOpiTvETF7FqUWOoA1NjbXpkoZ8R7CtoVcwzJpPCBucdJJyV+eqF0xXHoXjTSvm3/OQq2YladZqyjueGAoCIYjLTs+kzAbIxnPqpzm0Uu03P6DZ5cm3GXeziug4RFH4PP9nO126LhVDhlZM/9mr9upCLECJxz7N1QlFqm+WxLW4/aaAkiOg0WNZaZUctblhM9HXB66PcCspKXXZrWFrt4TMZ8dlKszfFOqll6AI3siCW3Bq3L/lsphBKRMTht7UH97IXq+EmVSh6ofNxtqR3mJypAadOOQSJsWW8jXKjUxeKX2SP1H5yi241SOr6HQ7A5FYo5q1MDkza/jMHs6HKoZp8CHSav79Dy5DmN1uKmCJZguC94nDhmqepvqh0iRH62eDKvd y7bPVKOO RLxEEhjOdXK12btwm+XJHGpUYrCoLpUjzBAu833wkMrvRRxPXL4ighABjCBKXFPgn2fixoKBftS/MVW6Eg6uNqyLrpUFwg9uQXngoMW5sVBAeAE3e2pgLToqTOM3ZDFQm/o/qWfKrkTeGnU1F5lOYPbAGThY9z/mvxhSCQ8nmiwn4/vQB6JHI4qJyyud/ioEMe7W7vpgea5P8KvbFloHUsqwjdbtn2yas3uwyc4FmMhQ1EQv0m8nX18Z72wznLtodbMNjvYL+WUFFKMlUHt1TwUS7Gw== 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 --- 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