Serge E. Hallyn wrote:
> Quoting Oren Laadan ([email protected]):
>> From: Dan Smith <[email protected]>
>>
>> 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 <[email protected]>
>> Signed-off-by: Oren Laadan <[email protected]>
>>
>> 1:
>> https://lists.linux-foundation.org/pipermail/containers/2009-February/015821.html
>> (all the way at the bottom)
>> ---
>> include/linux/checkpoint.h | 26 ++++++++++++++++++++++++++
>> 1 files changed, 26 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
>> index 69d14c4..2e99c74 100644
>> --- a/include/linux/checkpoint.h
>> +++ b/include/linux/checkpoint.h
>> @@ -117,6 +117,32 @@ extern int cr_read_mm(struct cr_ctx *ctx);
>> extern int cr_read_fd_table(struct cr_ctx *ctx);
>> extern int cr_read_file(struct cr_ctx *ctx, int objref);
>>
>> +/* useful macros to copy fields and buffers to/from cr_hdr_xxx structures */
>> +#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)
>> +
>
> Speaking from experience with similar sets of macros in capability.h,
> I'd like to suggest renaming a and b. Something like:
>
> #define CR_COPY(op, SAVED, LIVE) \
> do { \
> if (op == CR_CPT) \
> SAVED = LIVE; \
> else \
> LIVE = SAVED; \
> } while (0)
>
> That way the next time I need to use CR_COPY, I don't have to
> agonize over which argument goes where.
Good idea, done.
>
>> +/*
>> + * 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)
>> +
>> +
>> #define cr_debug(fmt, args...) \
>> pr_debug("[%d:c/r:%s] " fmt, task_pid_vnr(current), __func__, ## args)
>>
>> --
>> 1.5.4.3
>
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