As suggested by Dave[1], this provides us a way to make the copy-in and
copy-out processes symmetric. CR_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 CR_COPY_ARRAY
Feb 27:
. Changed CR_COPY() to use assignment, eliminating the need
for the CR_COPY_BIT() macro
. Add CR_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()
Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
1: https://lists.linux-foundation.org/pipermail/containers/2009-February/015821.html (all the way at the bottom)
---
include/linux/checkpoint.h | 23 +++++++++++++++++++++++
1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index e77393f..f748a75 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -120,6 +120,29 @@ static inline int cr_enabled(void)
return 1;
}
+#define CR_CPT 1
+#define CR_RST 2
+
+#define CR_COPY(op, a, b) \
+ do { \
+ if (op == CR_CPT) \
+ a = b; \
+ else \
+ b = a; \
+ } while (0)
+
+/* Copy @count items from @b to @a if op is CR_CPT (otherwise,
+ * copy in the reverse direction)
+ */
+#define CR_COPY_ARRAY(op, a, b, count) \
+ do { \
+ BUILD_BUG_ON(sizeof(*a) != sizeof(*b)); \
+ if (op == CR_CPT) \
+ memcpy(a, b, count * sizeof(*a)); \
+ else \
+ memcpy(b, a, count * sizeof(*a)); \
+ } while (__must_be_array(a) && __must_be_array(b) && 0)
+
#else /* !CONFIG_CHECKPOINT_RESTART */
static inline void files_deny_checkpointing(struct files_struct *files) {}
--
1.6.1
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