[rfc][patch] fs: mntput might sleep

[Nick Piggin <npiggin@suse.de>]

I missed this once or twice, so can we put might_sleep check into
mntput?  Or does anyone call it from atomic context to drop a known
not-last reference? (if so then maybe the caller could be rewritten).
--
Index: linux-2.6/include/linux/mount.h
===================================================================
--- linux-2.6.orig/include/linux/mount.h
+++ linux-2.6/include/linux/mount.h
@@ -113,6 +113,8 @@ extern int __mnt_is_readonly(struct vfsm
 static inline void mntput(struct vfsmount *mnt)
 {
 	if (mnt) {
+		might_sleep();
+
 		mnt->mnt_expiry_mark = 0;
 		mntput_no_expire(mnt);
 	}