From 7cf4dc3c8dbfdfde163d4636f621cf99a1f63bfb Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 15 Aug 2012 19:56:12 -0400 Subject: move files_struct-related bits from kernel/exit.c to fs/file.c Signed-off-by: Al Viro --- kernel/exit.c | 93 ----------------------------------------------------------- 1 file changed, 93 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index f65345f9e5bb..20dfc7617c2e 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -466,99 +466,6 @@ void daemonize(const char *name, ...) EXPORT_SYMBOL(daemonize); -static void close_files(struct files_struct * files) -{ - int i, j; - struct fdtable *fdt; - - j = 0; - - /* - * It is safe to dereference the fd table without RCU or - * ->file_lock because this is the last reference to the - * files structure. But use RCU to shut RCU-lockdep up. - */ - rcu_read_lock(); - fdt = files_fdtable(files); - rcu_read_unlock(); - for (;;) { - unsigned long set; - i = j * BITS_PER_LONG; - if (i >= fdt->max_fds) - break; - set = fdt->open_fds[j++]; - while (set) { - if (set & 1) { - struct file * file = xchg(&fdt->fd[i], NULL); - if (file) { - filp_close(file, files); - cond_resched(); - } - } - i++; - set >>= 1; - } - } -} - -struct files_struct *get_files_struct(struct task_struct *task) -{ - struct files_struct *files; - - task_lock(task); - files = task->files; - if (files) - atomic_inc(&files->count); - task_unlock(task); - - return files; -} - -void put_files_struct(struct files_struct *files) -{ - struct fdtable *fdt; - - if (atomic_dec_and_test(&files->count)) { - close_files(files); - /* - * Free the fd and fdset arrays if we expanded them. - * If the fdtable was embedded, pass files for freeing - * at the end of the RCU grace period. Otherwise, - * you can free files immediately. - */ - rcu_read_lock(); - fdt = files_fdtable(files); - if (fdt != &files->fdtab) - kmem_cache_free(files_cachep, files); - free_fdtable(fdt); - rcu_read_unlock(); - } -} - -void reset_files_struct(struct files_struct *files) -{ - struct task_struct *tsk = current; - struct files_struct *old; - - old = tsk->files; - task_lock(tsk); - tsk->files = files; - task_unlock(tsk); - put_files_struct(old); -} - -void exit_files(struct task_struct *tsk) -{ - struct files_struct * files = tsk->files; - - if (files) { - task_lock(tsk); - tsk->files = NULL; - task_unlock(tsk); - put_files_struct(files); - } -} - #ifdef CONFIG_MM_OWNER /* * A task is exiting. If it owned this mm, find a new owner for the mm. -- cgit v1.2.3 From 864bdb3b6cbd9911222543fef1cfe36f88183f44 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 22 Aug 2012 18:42:10 -0400 Subject: 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 --- fs/file.c | 6 ++++++ include/linux/fdtable.h | 1 + kernel/exit.c | 4 +--- 3 files changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel/exit.c') diff --git a/fs/file.c b/fs/file.c index e6e418122587..15750b80e3ce 100644 --- a/fs/file.c +++ b/fs/file.c @@ -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. */ diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index fb7dacae0522..45052aa814c8 100644 --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -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 *); diff --git a/kernel/exit.c b/kernel/exit.c index 20dfc7617c2e..095113321318 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -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(¤t->files->count); + daemonize_descriptors(); reparent_to_kthreadd(); } -- cgit v1.2.3