[For help] rdma-roce build quesiton

[For help] rdma-roce build quesiton

[oulijun]

Hi, Jason
I am building my userspace library code using cmake.
after i fix some lines, it is failed.

I directly called the min() from the ccan/minmax.h, the min()
as follows:

#if HAVE_BUILTIN_TYPES_COMPATIBLE_P
#define MINMAX_ASSERT_COMPATIBLE(a, b) \
BUILD_ASSERT(__builtin_types_compatible_p(a, b))
#else
#define MINMAX_ASSERT_COMPATIBLE(a, b) \
do { } while (0)
#endif

#define min(a, b) \
({ \
typeof(a) _a = (a); \
typeof(b) _b = (b); \
MINMAX_ASSERT_COMPATIBLE(typeof(_a), typeof(_b)); \
_a < _b ? _a : _b; \
})

and use #include <ccan/minmax.h> in my .c file where is used the min()

according to the modification, I use the cmd as follows:
CC=aarch64-linux-gnu-gcc cmake -GNinja -DENABLE_RESOLVE_NEIGH=0 -DHAVE_ARCH_ARM64=1 ..

the build is fail and the print log as follows:

error: size of unnamed array is negative
attr->cap.max_recv_wr = min(context->max_qp_wr, attr->cap.max_recv_wr);

Now, after fixed, the error is elimed. the fix as follows:
Fix the HAVE_BUILTIN_TYPES_COMPATIBLE_P for 0 in config.h.in or use the origin definition in my .h file

the origin defintion:
#define min(a, b) \
({ \
typeof(a) _a = (a); \
typeof(b) _b = (b); \
_a < _b ? _a : _b; \
})

but I think that the above modification is not a better approach
I try to change the Optimization Option(from -O0 to -O2) in aarch64-linux-gnu-gcc by finded some material.
CC=aarch64-linux-gnu-gcc cmake -O2 -GNinja -DENABLE_RESOLVE_NEIGH=0 -DHAVE_ARCH_ARM64=1 ..

But the error is not elimed.

Can you give me some guide?

thanks
Lijun ou

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Re: [For help] rdma-roce build quesiton

[Jason Gunthorpe]

On Wed, Oct 26, 2016 at 03:23:38PM +0800, oulijun wrote:

> the build is fail and the print log as follows:
> 
> error: size of unnamed array is negative
> attr->cap.max_recv_wr = min(context->max_qp_wr, attr->cap.max_recv_wr);

It is telling you the types are not the same, and this is a source of bugs
as C has some counter intuitive rules regarding type promotion.

1) Audit max_qp_wr and max_recv_wr to see if they really should be
   different types, if not fix context->max_qp_wr to match

2) If they are legitimately different then use

  min_t(<desired type>, context->max_qp_wr, attr->cap.max_recv_wr);

Think carefully about what common type is used because both arguments
will be casted, and the goal is to avoid a loss of precision or
signdedness in the cast.

Jason
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Re: [For help] rdma-roce build quesiton

[oulijun]

在 2016/10/27 0:09, Jason Gunthorpe 写道:
> On Wed, Oct 26, 2016 at 03:23:38PM +0800, oulijun wrote:
> 
>> the build is fail and the print log as follows:
>>
>> error: size of unnamed array is negative
>> attr->cap.max_recv_wr = min(context->max_qp_wr, attr->cap.max_recv_wr);
> 
> It is telling you the types are not the same, and this is a source of bugs
> as C has some counter intuitive rules regarding type promotion.
> 
> 1) Audit max_qp_wr and max_recv_wr to see if they really should be
>    different types, if not fix context->max_qp_wr to match
> 
> 2) If they are legitimately different then use
> 
>   min_t(<desired type>, context->max_qp_wr, attr->cap.max_recv_wr);
> 
> Think carefully about what common type is used because both arguments
> will be casted, and the goal is to avoid a loss of precision or
> signdedness in the cast.
> 
> Jason
> 
> .
> 
thanks, I see it.

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