[src/trunk]: src/sys/net update gif(4) locking notes.

[knakahara <knakahara%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/59c94fb19b28
branches:  trunk
changeset: 357779:59c94fb19b28
user:      knakahara <knakahara%NetBSD.org@localhost>
date:      Mon Nov 27 05:03:11 2017 +0000

description:
update gif(4) locking notes.

diffstat:

 sys/net/if_gif.h |  13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)

diffs (30 lines):

diff -r 420ff1ab6e22 -r 59c94fb19b28 sys/net/if_gif.h
--- a/sys/net/if_gif.h  Mon Nov 27 05:02:22 2017 +0000
+++ b/sys/net/if_gif.h  Mon Nov 27 05:03:11 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_gif.h,v 1.28 2017/11/27 05:02:22 knakahara Exp $    */
+/*     $NetBSD: if_gif.h,v 1.29 2017/11/27 05:03:11 knakahara Exp $    */
 /*     $KAME: if_gif.h,v 1.23 2001/07/27 09:21:42 itojun Exp $ */
 
 /*
@@ -140,14 +140,15 @@
  * + gif_softc_list is protected by gif_softcs.lock (an adaptive mutex)
  *       gif_softc_list is list of all gif_softcs. It is used by ioctl
  *       context only.
- * + Members of struct gif_softc except for gif_ro_percpu are protected by
- *   - encap_lock for writer
- *   - stopping processing when writer begin to run
- *     for reader(Tx and Rx processing)
+ * + gif_softc->gif_var is protected by
+ *   - gif_softc->gif_lock (an adaptive mutex) for writer
+ *   - gif_var->gv_psref for reader
+ *       gif_softc->gif_var is used for variant values while the gif tunnel
+ *       exists.
  * + Each CPU's gif_ro.gr_ro of gif_ro_percpu are protected by
  *   percpu'ed gif_ro.gr_lock.
  *
  * Locking order:
- *     - encap_lock => gif_softcs.lock
+ *     - encap_lock => gif_softc->gif_lock => gif_softcs.lock
  */
 #endif /* !_NET_IF_GIF_H_ */