diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-11-20 17:14:28 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2020-12-10 12:40:10 -0600 |
| commit | 3a879fb38082125cc0d8aa89b70c7f3a7cdf584b (patch) | |
| tree | bd61b89ba93e2810adc3c6bd8c44530e4a020c48 | |
| parent | 460b4f812a9d473d4b39d87d37844f9fc30a9eb3 (diff) | |
file: Implement task_lookup_fd_rcu
As a companion to lookup_fd_rcu implement task_lookup_fd_rcu for
querying an arbitrary process about a specific file.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
v1: https://lkml.kernel.org/r/20200818103713.aw46m7vprsy4vlve@wittgenstein
Link: https://lkml.kernel.org/r/20201120231441.29911-11-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| -rw-r--r-- | fs/file.c | 15 | ||||
| -rw-r--r-- | include/linux/fdtable.h | 2 |
2 files changed, 17 insertions, 0 deletions
diff --git a/fs/file.c b/fs/file.c index 5861c4f89419..6448523ca29e 100644 --- a/fs/file.c +++ b/fs/file.c @@ -865,6 +865,21 @@ struct file *fget_task(struct task_struct *task, unsigned int fd) return file; } +struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd) +{ + /* Must be called with rcu_read_lock held */ + struct files_struct *files; + struct file *file = NULL; + + task_lock(task); + files = task->files; + if (files) + file = files_lookup_fd_rcu(files, fd); + task_unlock(task); + + return file; +} + /* * Lightweight file lookup - no refcnt increment if fd table isn't shared. * diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index 2a4a8fed536e..a0558ae9b40c 100644 --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -110,6 +110,8 @@ static inline struct file *lookup_fd_rcu(unsigned int fd) return files_lookup_fd_rcu(current->files, fd); } +struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd); + struct task_struct; struct files_struct *get_files_struct(struct task_struct *); |