uninline may_mount() and don't opencode it in fspick(2)/fsopen(2)

It's done once per (mount-related) syscall and there's no point
whatsoever making it inline.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/fsopen.c

@@ -119,7 +119,7 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
 	const char *fs_name;
 	int ret;
 
-	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+	if (!may_mount())
 		return -EPERM;
 
 	if (flags & ~FSOPEN_CLOEXEC)
@@ -162,7 +162,7 @@ SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags
 	unsigned int lookup_flags;
 	int ret;
 
-	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+	if (!may_mount())
 		return -EPERM;
 
 	if ((flags & ~(FSPICK_CLOEXEC |

fs/internal.h

@@ -84,6 +84,7 @@ extern int __mnt_want_write_file(struct file *);
 extern void __mnt_drop_write_file(struct file *);
 
 extern void dissolve_on_fput(struct vfsmount *);
+extern bool may_mount(void);
 
 int path_mount(const char *dev_name, struct path *path,
 		const char *type_page, unsigned long flags, void *data_page);

fs/namespace.c

@@ -1760,7 +1760,7 @@ void __detach_mounts(struct dentry *dentry)
 /*
  * Is the caller allowed to modify his namespace?
  */
-static inline bool may_mount(void)
+bool may_mount(void)
 {
 	return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
 }