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From: Oren Laadan on 1 May 2010 10:50
From: Dan Smith <danms(a)us.ibm.com>

As suggested by Dave[1], this provides us a way to make the copy-in and
copy-out processes symmetric. CKPT_COPY_ARRAY() provides us a way to do
the same thing but for arrays. It's not critical, but it helps us unify
the checkpoint and restart paths for some things.

Changelog:
Mar 04:
. Removed semicolons
. Added build-time check for __must_be_array in CKPT_COPY_ARRAY
Feb 27:
. Changed CKPT_COPY() to use assignment, eliminating the need
for the CKPT_COPY_BIT() macro
. Add CKPT_COPY_ARRAY() macro to help copying register arrays,
etc
. Move the macro definitions inside the CR #ifdef
Feb 25:
. Changed WARN_ON() to BUILD_BUG_ON()

Cc: linux-s390(a)vger.kernel.org
Signed-off-by: Dan Smith <danms(a)us.ibm.com>
Signed-off-by: Oren Laadan <orenl(a)cs.columbia.edu>
Acked-by: Serge E. Hallyn <serue(a)us.ibm.com>
Tested-by: Serge E. Hallyn <serue(a)us.ibm.com>

1: https://lists.linux-foundation.org/pipermail/containers/2009-February/015821.html (all the way at the bottom)
---
include/linux/checkpoint.h | 28 ++++++++++++++++++++++++++++
1 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 2f72a6a..cd76f70 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -246,6 +246,34 @@ static inline int ckpt_validate_errno(int errno)
return (errno >= 0) && (errno < MAX_ERRNO);
}

+/* useful macros to copy fields and buffers to/from ckpt_hdr_xxx structures */
+#define CKPT_CPT 1
+#define CKPT_RST 2
+
+#define CKPT_COPY(op, SAVE, LIVE) \
+ do { \
+ if (op == CKPT_CPT) \
+ SAVE = LIVE; \
+ else \
+ LIVE = SAVE; \
+ } while (0)
+
+/*
+ * Copy @count items from @LIVE to @SAVE if op is CKPT_CPT (otherwise,
+ * copy in the reverse direction)
+ */
+#define CKPT_COPY_ARRAY(op, SAVE, LIVE, count) \
+ do { \
+ (void)__must_be_array(SAVE); \
+ (void)__must_be_array(LIVE); \
+ BUILD_BUG_ON(sizeof(*SAVE) != sizeof(*LIVE)); \
+ if (op == CKPT_CPT) \
+ memcpy(SAVE, LIVE, count * sizeof(*SAVE)); \
+ else \
+ memcpy(LIVE, SAVE, count * sizeof(*SAVE)); \
+ } while (0)
+
+
/* debugging flags */
#define CKPT_DBASE 0x1 /* anything */
#define CKPT_DSYS 0x2 /* generic (system) */
--
1.6.3.3

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