fs/kernel_read_file: Add file_size output argument

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can reason more easily about their reading progress.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-8-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h
index 910039e7593e..023293eaf948 100644
--- a/include/linux/kernel_read_file.h
+++ b/include/linux/kernel_read_file.h
@@ -37,15 +37,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
 
 int kernel_read_file(struct file *file,
 		     void **buf, size_t buf_size,
+		     size_t *file_size,
 		     enum kernel_read_file_id id);
 int kernel_read_file_from_path(const char *path,
 			       void **buf, size_t buf_size,
+			       size_t *file_size,
 			       enum kernel_read_file_id id);
 int kernel_read_file_from_path_initns(const char *path,
 				      void **buf, size_t buf_size,
+				      size_t *file_size,
 				      enum kernel_read_file_id id);
 int kernel_read_file_from_fd(int fd,
 			     void **buf, size_t buf_size,
+			     size_t *file_size,
 			     enum kernel_read_file_id id);
 
 #endif /* _LINUX_KERNEL_READ_FILE_H */