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From: Eitan Adler <eadler@FreeBSD.org>
Date: Mon, 19 Mar 2018 03:04:19 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r331158 - stable/11/sys/sys
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Author: eadler
Date: Mon Mar 19 03:04:19 2018
New Revision: 331158
URL: https://svnweb.freebsd.org/changeset/base/331158

Log:
  MFC r314052:
  
  Document what the different flags mean for locking.

Modified:
  stable/11/sys/sys/bufobj.h
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/sys/bufobj.h
==============================================================================
--- stable/11/sys/sys/bufobj.h	Mon Mar 19 02:46:17 2018	(r331157)
+++ stable/11/sys/sys/bufobj.h	Mon Mar 19 03:04:19 2018	(r331158)
@@ -90,6 +90,12 @@ struct buf_ops {
 #define BO_WRITE(bo, bp)	((bo)->bo_ops->bop_write((bp)))
 #define BO_BDFLUSH(bo, bp)	((bo)->bo_ops->bop_bdflush((bo), (bp)))
 
+/*
+ * Locking notes:
+ * 'S' is sync_mtx
+ * 'v' is the vnode lock which embeds the bufobj.
+ * '-' Constant and unchanging after initialization.
+ */
 struct bufobj {
 	struct rwlock	bo_lock;	/* Lock which protects "i" things */
 	struct buf_ops	*bo_ops;	/* - Buffer operations */