path_mount() wants the mount data if not NULL to be a whole
page. Expanding a string onto an allocated page was done in
do_mount_root(); move it instead into init_mount() so other users of
init_mount() can leverage this same code.

Signed-off-by: H. Peter Anvin (Intel) <[email protected]>
---
 fs/init.c                     | 23 ++++++++++++++++++++---
 include/linux/init_syscalls.h |  3 ++-
 init/do_mounts.c              | 17 ++---------------
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/fs/init.c b/fs/init.c
index e0f5429c0a49..1253bcc73e26 100644
--- a/fs/init.c
+++ b/fs/init.c
@@ -14,16 +14,33 @@
 #include "internal.h"
 
 int __init init_mount(const char *dev_name, const char *dir_name,
-               const char *type_page, unsigned long flags, void *data_page)
+                     const char *type_page, unsigned long flags,
+                     const char *data_str)
 {
+       struct page *data_page = NULL;
+       char *data_buf = NULL;
        struct path path;
        int ret;
 
+       /* path_mount() wants a proper page for data */
+       if (data_str && data_str[0]) {
+               data_page = alloc_page(GFP_KERNEL);
+               if (!data_page)
+                       return -ENOMEM;
+               data_buf = page_address(data_page);
+               strscpy_pad(data_buf, data_str, PAGE_SIZE);
+       }
+
        ret = kern_path(dir_name, LOOKUP_FOLLOW, &path);
        if (ret)
-               return ret;
-       ret = path_mount(dev_name, &path, type_page, flags, data_page);
+               goto out;
+
+       ret = path_mount(dev_name, &path, type_page, flags, data_buf);
        path_put(&path);
+
+out:
+       if (data_page)
+               put_page(data_page);
        return ret;
 }
 
diff --git a/include/linux/init_syscalls.h b/include/linux/init_syscalls.h
index 92045d18cbfc..804d3070ce73 100644
--- a/include/linux/init_syscalls.h
+++ b/include/linux/init_syscalls.h
@@ -1,7 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 
 int __init init_mount(const char *dev_name, const char *dir_name,
-               const char *type_page, unsigned long flags, void *data_page);
+                     const char *type_page, unsigned long flags,
+                     const char *data_str);
 int __init init_umount(const char *name, int flags);
 int __init init_chdir(const char *filename);
 int __init init_chroot(const char *filename);
diff --git a/init/do_mounts.c b/init/do_mounts.c
index defbbf1d55f7..87cf110a48e6 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -147,23 +147,12 @@ static int __init split_fs_names(char *page, size_t size)
 }
 
 static int __init do_mount_root(const char *name, const char *fs,
-                                const int flags, const void *data)
+                                const int flags, const char *data)
 {
        struct super_block *s;
-       struct page *p = NULL;
-       char *data_page = NULL;
        int ret;
 
-       if (data) {
-               /* init_mount() requires a full page as fifth argument */
-               p = alloc_page(GFP_KERNEL);
-               if (!p)
-                       return -ENOMEM;
-               data_page = page_address(p);
-               strscpy_pad(data_page, data, PAGE_SIZE);
-       }
-
-       ret = init_mount(name, "/root", fs, flags, data_page);
+       ret = init_mount(name, "/root", fs, flags, data);
        if (ret)
                goto out;
 
@@ -177,8 +166,6 @@ static int __init do_mount_root(const char *name, const 
char *fs,
               MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
 
 out:
-       if (p)
-               put_page(p);
        return ret;
 }
 
-- 
2.52.0

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