take descriptor-related part of close() to file.c

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

drivers/staging/android/binder.c

@@ -390,43 +390,17 @@ static void task_fd_install(
 		__fd_install(proc->files, fd, file);
 }
 
-/*
- * copied from __put_unused_fd in open.c
- */
-static void __put_unused_fd(struct files_struct *files, unsigned int fd)
-{
-	struct fdtable *fdt = files_fdtable(files);
-	__clear_open_fd(fd, fdt);
-	if (fd < files->next_fd)
-		files->next_fd = fd;
-}
-
 /*
  * copied from sys_close
  */
 static long task_close_fd(struct binder_proc *proc, unsigned int fd)
 {
-	struct file *filp;
-	struct files_struct *files = proc->files;
-	struct fdtable *fdt;
 	int retval;
 
-	if (files == NULL)
+	if (proc->files == NULL)
 		return -ESRCH;
 
-	spin_lock(&files->file_lock);
-	fdt = files_fdtable(files);
-	if (fd >= fdt->max_fds)
-		goto out_unlock;
-	filp = fdt->fd[fd];
-	if (!filp)
-		goto out_unlock;
-	rcu_assign_pointer(fdt->fd[fd], NULL);
-	__clear_close_on_exec(fd, fdt);
-	__put_unused_fd(files, fd);
-	spin_unlock(&files->file_lock);
-	retval = filp_close(filp, files);
-
+	retval = __close_fd(proc->files, fd);
 	/* can't restart close syscall because file table entry was cleared */
 	if (unlikely(retval == -ERESTARTSYS ||
 		     retval == -ERESTARTNOINTR ||
@@ -435,10 +409,6 @@ static long task_close_fd(struct binder_proc *proc, unsigned int fd)
 		retval = -EINTR;
 
 	return retval;
-
-out_unlock:
-	spin_unlock(&files->file_lock);
-	return -EBADF;
 }
 
 static void binder_set_nice(long nice)

fs/file.c

@@ -626,6 +626,32 @@ void fd_install(unsigned int fd, struct file *file)
 
 EXPORT_SYMBOL(fd_install);
 
+/*
+ * The same warnings as for __alloc_fd()/__fd_install() apply here...
+ */
+int __close_fd(struct files_struct *files, unsigned fd)
+{
+	struct file *file;
+	struct fdtable *fdt;
+
+	spin_lock(&files->file_lock);
+	fdt = files_fdtable(files);
+	if (fd >= fdt->max_fds)
+		goto out_unlock;
+	file = fdt->fd[fd];
+	if (!file)
+		goto out_unlock;
+	rcu_assign_pointer(fdt->fd[fd], NULL);
+	__clear_close_on_exec(fd, fdt);
+	__put_unused_fd(files, fd);
+	spin_unlock(&files->file_lock);
+	return filp_close(file, files);
+
+out_unlock:
+	spin_unlock(&files->file_lock);
+	return -EBADF;
+}
+
 struct file *fget(unsigned int fd)
 {
 	struct file *file;

fs/open.c

@@ -994,23 +994,7 @@ EXPORT_SYMBOL(filp_close);
  */
 SYSCALL_DEFINE1(close, unsigned int, fd)
 {
-	struct file * filp;
-	struct files_struct *files = current->files;
-	struct fdtable *fdt;
-	int retval;
-
-	spin_lock(&files->file_lock);
-	fdt = files_fdtable(files);
-	if (fd >= fdt->max_fds)
-		goto out_unlock;
-	filp = fdt->fd[fd];
-	if (!filp)
-		goto out_unlock;
-	rcu_assign_pointer(fdt->fd[fd], NULL);
-	__clear_close_on_exec(fd, fdt);
-	__put_unused_fd(files, fd);
-	spin_unlock(&files->file_lock);
-	retval = filp_close(filp, files);
+	int retval = __close_fd(current->files, fd);
 
 	/* can't restart close syscall because file table entry was cleared */
 	if (unlikely(retval == -ERESTARTSYS ||
@@ -1020,10 +1004,6 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
 		retval = -EINTR;
 
 	return retval;
-
-out_unlock:
-	spin_unlock(&files->file_lock);
-	return -EBADF;
 }
 EXPORT_SYMBOL(sys_close);
 

include/linux/fdtable.h

@@ -123,6 +123,8 @@ extern int __alloc_fd(struct files_struct *files,
 		      unsigned start, unsigned end, unsigned flags);
 extern void __fd_install(struct files_struct *files,
 		      unsigned int fd, struct file *file);
+extern int __close_fd(struct files_struct *files,
+		      unsigned int fd);
 
 extern struct kmem_cache *files_cachep;