diff options
| -rw-r--r-- | fs/file.c | 106 | ||||
| -rw-r--r-- | fs/file_table.c | 106 |
2 files changed, 106 insertions, 106 deletions
diff --git a/fs/file.c b/fs/file.c index 0d1bf0515111..6eef55ce30c9 100644 --- a/fs/file.c +++ b/fs/file.c @@ -625,3 +625,109 @@ void fd_install(unsigned int fd, struct file *file) } EXPORT_SYMBOL(fd_install); + +struct file *fget(unsigned int fd) +{ + struct file *file; + struct files_struct *files = current->files; + + rcu_read_lock(); + file = fcheck_files(files, fd); + if (file) { + /* File object ref couldn't be taken */ + if (file->f_mode & FMODE_PATH || + !atomic_long_inc_not_zero(&file->f_count)) + file = NULL; + } + rcu_read_unlock(); + + return file; +} + +EXPORT_SYMBOL(fget); + +struct file *fget_raw(unsigned int fd) +{ + struct file *file; + struct files_struct *files = current->files; + + rcu_read_lock(); + file = fcheck_files(files, fd); + if (file) { + /* File object ref couldn't be taken */ + if (!atomic_long_inc_not_zero(&file->f_count)) + file = NULL; + } + rcu_read_unlock(); + + return file; +} + +EXPORT_SYMBOL(fget_raw); + +/* + * Lightweight file lookup - no refcnt increment if fd table isn't shared. + * + * You can use this instead of fget if you satisfy all of the following + * conditions: + * 1) You must call fput_light before exiting the syscall and returning control + * to userspace (i.e. you cannot remember the returned struct file * after + * returning to userspace). + * 2) You must not call filp_close on the returned struct file * in between + * calls to fget_light and fput_light. + * 3) You must not clone the current task in between the calls to fget_light + * and fput_light. + * + * The fput_needed flag returned by fget_light should be passed to the + * corresponding fput_light. + */ +struct file *fget_light(unsigned int fd, int *fput_needed) +{ + struct file *file; + struct files_struct *files = current->files; + + *fput_needed = 0; + if (atomic_read(&files->count) == 1) { + file = fcheck_files(files, fd); + if (file && (file->f_mode & FMODE_PATH)) + file = NULL; + } else { + rcu_read_lock(); + file = fcheck_files(files, fd); + if (file) { + if (!(file->f_mode & FMODE_PATH) && + atomic_long_inc_not_zero(&file->f_count)) + *fput_needed = 1; + else + /* Didn't get the reference, someone's freed */ + file = NULL; + } + rcu_read_unlock(); + } + + return file; +} + +struct file *fget_raw_light(unsigned int fd, int *fput_needed) +{ + struct file *file; + struct files_struct *files = current->files; + + *fput_needed = 0; + if (atomic_read(&files->count) == 1) { + file = fcheck_files(files, fd); + } else { + rcu_read_lock(); + file = fcheck_files(files, fd); + if (file) { + if (atomic_long_inc_not_zero(&file->f_count)) + *fput_needed = 1; + else + /* Didn't get the reference, someone's freed */ + file = NULL; + } + rcu_read_unlock(); + } + + return file; +} diff --git a/fs/file_table.c b/fs/file_table.c index 701985e4ccda..c6780163bf3e 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -339,112 +339,6 @@ void __fput_sync(struct file *file) EXPORT_SYMBOL(fput); -struct file *fget(unsigned int fd) -{ - struct file *file; - struct files_struct *files = current->files; - - rcu_read_lock(); - file = fcheck_files(files, fd); - if (file) { - /* File object ref couldn't be taken */ - if (file->f_mode & FMODE_PATH || - !atomic_long_inc_not_zero(&file->f_count)) - file = NULL; - } - rcu_read_unlock(); - - return file; -} - -EXPORT_SYMBOL(fget); - -struct file *fget_raw(unsigned int fd) -{ - struct file *file; - struct files_struct *files = current->files; - - rcu_read_lock(); - file = fcheck_files(files, fd); - if (file) { - /* File object ref couldn't be taken */ - if (!atomic_long_inc_not_zero(&file->f_count)) - file = NULL; - } - rcu_read_unlock(); - - return file; -} - -EXPORT_SYMBOL(fget_raw); - -/* - * Lightweight file lookup - no refcnt increment if fd table isn't shared. - * - * You can use this instead of fget if you satisfy all of the following - * conditions: - * 1) You must call fput_light before exiting the syscall and returning control - * to userspace (i.e. you cannot remember the returned struct file * after - * returning to userspace). - * 2) You must not call filp_close on the returned struct file * in between - * calls to fget_light and fput_light. - * 3) You must not clone the current task in between the calls to fget_light - * and fput_light. - * - * The fput_needed flag returned by fget_light should be passed to the - * corresponding fput_light. - */ -struct file *fget_light(unsigned int fd, int *fput_needed) -{ - struct file *file; - struct files_struct *files = current->files; - - *fput_needed = 0; - if (atomic_read(&files->count) == 1) { - file = fcheck_files(files, fd); - if (file && (file->f_mode & FMODE_PATH)) - file = NULL; - } else { - rcu_read_lock(); - file = fcheck_files(files, fd); - if (file) { - if (!(file->f_mode & FMODE_PATH) && - atomic_long_inc_not_zero(&file->f_count)) - *fput_needed = 1; - else - /* Didn't get the reference, someone's freed */ - file = NULL; - } - rcu_read_unlock(); - } - - return file; -} - -struct file *fget_raw_light(unsigned int fd, int *fput_needed) -{ - struct file *file; - struct files_struct *files = current->files; - - *fput_needed = 0; - if (atomic_read(&files->count) == 1) { - file = fcheck_files(files, fd); - } else { - rcu_read_lock(); - file = fcheck_files(files, fd); - if (file) { - if (atomic_long_inc_not_zero(&file->f_count)) - *fput_needed = 1; - else - /* Didn't get the reference, someone's freed */ - file = NULL; - } - rcu_read_unlock(); - } - - return file; -} - void put_filp(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { |