new helper: daemonize_descriptors()

descriptor-related parts of daemonize, done right.  As the
result we simplify the locking rules for ->files - we
hold task_lock in *all* cases when we modify ->files.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-08-22 18:42:10 -04:00
parent 2be7fd55d4
commit 864bdb3b6c
3 changed files with 8 additions and 3 deletions

View File

@ -519,6 +519,12 @@ struct files_struct init_files = {
.file_lock = __SPIN_LOCK_UNLOCKED(init_task.file_lock),
};
void daemonize_descriptors(void)
{
atomic_inc(&init_files.count);
reset_files_struct(&init_files);
}
/*
* allocate a file descriptor, mark it busy.
*/

View File

@ -95,6 +95,7 @@ struct task_struct;
struct files_struct *get_files_struct(struct task_struct *);
void put_files_struct(struct files_struct *fs);
void reset_files_struct(struct files_struct *);
void daemonize_descriptors(void);
int unshare_files(struct files_struct **);
struct files_struct *dup_fd(struct files_struct *, int *);
void do_close_on_exec(struct files_struct *);

View File

@ -457,9 +457,7 @@ void daemonize(const char *name, ...)
/* Become as one with the init task */
daemonize_fs_struct();
exit_files(current);
current->files = init_task.files;
atomic_inc(&current->files->count);
daemonize_descriptors();
reparent_to_kthreadd();
}