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    Subject[PATCH v21 059/100] c/r: add CKPT_COPY() macro
    Date
    From: Dan Smith <danms@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@vger.kernel.org
    Signed-off-by: Dan Smith <danms@us.ibm.com>
    Signed-off-by: Oren Laadan <orenl@cs.columbia.edu>
    Acked-by: Serge E. Hallyn <serue@us.ibm.com>
    Tested-by: Serge E. Hallyn <serue@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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