Take fs_struct handling to new file (fs/fs_struct.c)

Pure code move; two new helper functions for nfsd and daemonize
(unshare_fs_struct() and daemonize_fs_struct() resp.; for now -
the same code as used to be in callers).  unshare_fs_struct()
exported (for nfsd, as copy_fs_struct()/exit_fs() used to be),
copy_fs_struct() and exit_fs() don't need exports anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 3 insertions, 57 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 167e1e3ad7c6..ad8375758a79 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -429,7 +429,6 @@ EXPORT_SYMBOL(disallow_signal);
 void daemonize(const char *name, ...)
 {
         va_list args;
-        struct fs_struct *fs;
         sigset_t blocked;
 
         va_start(args, name);
@@ -462,11 +461,7 @@ void daemonize(const char *name, ...)
 
         /* Become as one with the init task */
 
-        exit_fs(current);       /* current->fs->count--; */
-        fs = init_task.fs;
-        current->fs = fs;
-        atomic_inc(&fs->count);
-
+        daemonize_fs_struct();
         exit_files(current);
         current->files = init_task.files;
         atomic_inc(&current->files->count);
@@ -565,30 +560,6 @@ void exit_files(struct task_struct *tsk)
         }
 }
 
-void put_fs_struct(struct fs_struct *fs)
-{
-        /* No need to hold fs->lock if we are killing it */
-        if (atomic_dec_and_test(&fs->count)) {
-                path_put(&fs->root);
-                path_put(&fs->pwd);
-                kmem_cache_free(fs_cachep, fs);
-        }
-}
-
-void exit_fs(struct task_struct *tsk)
-{
-        struct fs_struct * fs = tsk->fs;
-
-        if (fs) {
-                task_lock(tsk);
-                tsk->fs = NULL;
-                task_unlock(tsk);
-                put_fs_struct(fs);
-        }
-}
-
-EXPORT_SYMBOL_GPL(exit_fs);
-
 #ifdef CONFIG_MM_OWNER
 /*
  * Task p is exiting and it owned mm, lets find a new owner for it
diff --git a/kernel/fork.c b/kernel/fork.c
index 47c15840a381..05c02dc586b1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -681,38 +681,13 @@ fail_nomem:
         return retval;
 }
 
-static struct fs_struct *__copy_fs_struct(struct fs_struct *old)
-{
-        struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
-        /* We don't need to lock fs - think why ;-) */
-        if (fs) {
-                atomic_set(&fs->count, 1);
-                rwlock_init(&fs->lock);
-                fs->umask = old->umask;
-                read_lock(&old->lock);
-                fs->root = old->root;
-                path_get(&old->root);
-                fs->pwd = old->pwd;
-                path_get(&old->pwd);
-                read_unlock(&old->lock);
-        }
-        return fs;
-}
-
-struct fs_struct *copy_fs_struct(struct fs_struct *old)
-{
-        return __copy_fs_struct(old);
-}
-
-EXPORT_SYMBOL_GPL(copy_fs_struct);
-
 static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
 {
         if (clone_flags & CLONE_FS) {
                 atomic_inc(&current->fs->count);
                 return 0;
         }
-        tsk->fs = __copy_fs_struct(current->fs);
+        tsk->fs = copy_fs_struct(current->fs);
         if (!tsk->fs)
                 return -ENOMEM;
         return 0;
@@ -1545,7 +1520,7 @@ static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
 
         if ((unshare_flags & CLONE_FS) &&
             (fs && atomic_read(&fs->count) > 1)) {
-                *new_fsp = __copy_fs_struct(current->fs);
+                *new_fsp = copy_fs_struct(current->fs);
                 if (!*new_fsp)
                         return -ENOMEM;
         }