Merge branch 'vfs.file'

Bring in the changes to the file infrastructure for this cycle. Mostly
cleanups and some performance tweaks.

* file: remove __receive_fd()
* file: stop exposing receive_fd_user()
* fs: replace f_rcuhead with f_task_work
* file: remove pointless wrapper
* file: s/close_fd_get_file()/file_close_fd()/g
* Improve __fget_files_rcu() code generation (and thus __fget_light())
* file: massage cleanup of files that failed to open

Signed-off-by: Christian Brauner <brauner@kernel.org>

3 files changed, 16 insertions, 19 deletions

diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index bc4c3287a65e..78c8326d74ae 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -83,12 +83,17 @@ struct dentry;
 static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd)
 {
 	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
-
-	if (fd < fdt->max_fds) {
-		fd = array_index_nospec(fd, fdt->max_fds);
-		return rcu_dereference_raw(fdt->fd[fd]);
-	}
-	return NULL;
+	unsigned long mask = array_index_mask_nospec(fd, fdt->max_fds);
+	struct file *needs_masking;
+
+	/*
+	 * 'mask' is zero for an out-of-bounds fd, all ones for ok.
+	 * 'fd&mask' is 'fd' for ok, or 0 for out of bounds.
+	 *
+	 * Accessing fdt->fd[0] is ok, but needs masking of the result.
+	 */
+	needs_masking = rcu_dereference_raw(fdt->fd[fd&mask]);
+	return (struct file *)(mask & (unsigned long)needs_masking);
 }
 
 static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd)
@@ -114,7 +119,7 @@ int iterate_fd(struct files_struct *, unsigned,
 
 extern int close_fd(unsigned int fd);
 extern int __close_range(unsigned int fd, unsigned int max_fd, unsigned int flags);
-extern struct file *close_fd_get_file(unsigned int fd);
+extern struct file *file_close_fd(unsigned int fd);
 extern int unshare_fd(unsigned long unshare_flags, unsigned int max_fds,
 		      struct files_struct **new_fdp);
 
diff --git a/include/linux/file.h b/include/linux/file.h
index 6e9099d29343..6834a29338c4 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -96,18 +96,8 @@ DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
 
 extern void fd_install(unsigned int fd, struct file *file);
 
-extern int __receive_fd(struct file *file, int __user *ufd,
-			unsigned int o_flags);
+int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
 
-extern int receive_fd(struct file *file, unsigned int o_flags);
-
-static inline int receive_fd_user(struct file *file, int __user *ufd,
-				  unsigned int o_flags)
-{
-	if (ufd == NULL)
-		return -EFAULT;
-	return __receive_fd(file, ufd, o_flags);
-}
 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
 
 extern void flush_delayed_fput(void);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a3a48a5d8728..3d58376ed39e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -991,8 +991,10 @@ static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
  */
 struct file {
 	union {
+		/* fput() uses task work when closing and freeing file (default). */
+		struct callback_head 	f_task_work;
+		/* fput() must use workqueue (most kernel threads). */
 		struct llist_node	f_llist;
-		struct rcu_head 	f_rcuhead;
 		unsigned int 		f_iocb_flags;
 	};