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Tue, 19 Nov 2024 17:56:05 +0000 From: Juntong Deng To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, memxor@gmail.com, snorcht@gmail.com, brauner@kernel.org Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH bpf-next v4 3/5] bpf: Add bpf_fget_task() kfunc Date: Tue, 19 Nov 2024 17:54:00 +0000 Message-ID: X-Mailer: git-send-email 2.39.5 In-Reply-To: References: X-ClientProxiedBy: LO2P265CA0187.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:a::31) To AM6PR03MB5080.eurprd03.prod.outlook.com (2603:10a6:20b:90::20) X-Microsoft-Original-Message-ID: <20241119175402.51778-3-juntong.deng@outlook.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AM6PR03MB5080:EE_|DB8PR03MB6170:EE_ X-MS-Office365-Filtering-Correlation-Id: 1acd5c80-4df3-4e77-ca5f-08dd08c3701b X-Microsoft-Antispam: BCL:0;ARA:14566002|5072599009|461199028|19110799003|8060799006|15080799006|440099028|3412199025; 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Note that this function acquires a reference to struct file. Signed-off-by: Juntong Deng --- fs/bpf_fs_kfuncs.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/fs/bpf_fs_kfuncs.c b/fs/bpf_fs_kfuncs.c index 3fe9f59ef867..19a9d45c47f9 100644 --- a/fs/bpf_fs_kfuncs.c +++ b/fs/bpf_fs_kfuncs.c @@ -152,6 +152,26 @@ __bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str, return bpf_get_dentry_xattr(dentry, name__str, value_p); } +/** + * bpf_fget_task() - Get a pointer to the struct file corresponding to + * the task file descriptor + * + * Note that this function acquires a reference to struct file. + * + * @task: the specified struct task_struct + * @fd: the file descriptor + * + * @returns the corresponding struct file pointer if found, + * otherwise returns NULL + */ +__bpf_kfunc struct file *bpf_fget_task(struct task_struct *task, unsigned int fd) +{ + struct file *file; + + file = fget_task(task, fd); + return file; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(bpf_fs_kfunc_set_ids) @@ -161,6 +181,7 @@ BTF_ID_FLAGS(func, bpf_put_file, KF_RELEASE) BTF_ID_FLAGS(func, bpf_path_d_path, KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_get_dentry_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_fget_task, KF_ACQUIRE | KF_TRUSTED_ARGS | KF_RET_NULL) BTF_KFUNCS_END(bpf_fs_kfunc_set_ids) static int bpf_fs_kfuncs_filter(const struct bpf_prog *prog, u32 kfunc_id)