librdmacm in rdma-core build warnings

librdmacm in rdma-core build warnings

[Leon Romanovsky]

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Hi All,

After moving to gcc version 7.2.0 (GCC), I started experience the
following compilation warning with default build.sh supplied with
rdma-core.

[26/189] Building C object librdmacm/CMakeFiles/rspreload.dir/preload.c.o
../librdmacm/preload.c:818:9: warning: no previous prototype for ‘readv’ [-Wmissing-prototypes]
 ssize_t readv(int socket, const struct iovec *iov, int iovcnt)
         ^~~~~
../librdmacm/preload.c:857:9: warning: no previous prototype for ‘writev’ [-Wmissing-prototypes]
 ssize_t writev(int socket, const struct iovec *iov, int iovcnt)

The code to enable -Wmissing-prototypes checks is part of the rdma-core
for a year now, see commit: b192ed2347e5 ("Enable -Wmissing-prototypes/-Wmissing-declarations")

The fact that librdmacm/preload.c uses combination of RTLD_NEXT and
dlsym to set readv/writev scares me to just delete readv and writev calls,
because it is most probably wrong.

Any ideas how to fix it?

Thanks

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RE: librdmacm in rdma-core build warnings

[Hefty, Sean]

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> [26/189] Building C object
> librdmacm/CMakeFiles/rspreload.dir/preload.c.o
> ../librdmacm/preload.c:818:9: warning: no previous prototype for
> ‘readv’ [-Wmissing-prototypes]  ssize_t readv(int socket, const struct
> iovec *iov, int iovcnt)
>          ^~~~~
> ../librdmacm/preload.c:857:9: warning: no previous prototype for
> ‘writev’ [-Wmissing-prototypes]  ssize_t writev(int socket, const
> struct iovec *iov, int iovcnt)

Does including sys/uio.h fix this?

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Re: librdmacm in rdma-core build warnings

[Jason Gunthorpe]

On Mon, Oct 02, 2017 at 04:11:01PM +0000, Hefty, Sean wrote:
> > [26/189] Building C object
> > librdmacm/CMakeFiles/rspreload.dir/preload.c.o
> > ../librdmacm/preload.c:818:9: warning: no previous prototype for
> > ???readv??? [-Wmissing-prototypes]  ssize_t readv(int socket, const struct
> > iovec *iov, int iovcnt)
> >          ^~~~~
> > ../librdmacm/preload.c:857:9: warning: no previous prototype for
> > ???writev??? [-Wmissing-prototypes]  ssize_t writev(int socket, const
> > struct iovec *iov, int iovcnt)
> 
> Does including sys/uio.h fix this?

Something like that is the right solution, probably caused by glibc
changes not gcc changes...

The prototype must come from glibc headers.

Jason
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Re: librdmacm in rdma-core build warnings

[Leon Romanovsky]

On Mon, Oct 2, 2017 at 8:54 PM, Jason Gunthorpe
<jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> wrote:
> On Mon, Oct 02, 2017 at 04:11:01PM +0000, Hefty, Sean wrote:
>> > [26/189] Building C object
>> > librdmacm/CMakeFiles/rspreload.dir/preload.c.o
>> > ../librdmacm/preload.c:818:9: warning: no previous prototype for
>> > ???readv??? [-Wmissing-prototypes]  ssize_t readv(int socket, const struct
>> > iovec *iov, int iovcnt)
>> >          ^~~~~
>> > ../librdmacm/preload.c:857:9: warning: no previous prototype for
>> > ???writev??? [-Wmissing-prototypes]  ssize_t writev(int socket, const
>> > struct iovec *iov, int iovcnt)
>>
>> Does including sys/uio.h fix this?
>
> Something like that is the right solution, probably caused by glibc
> changes not gcc changes...
>
> The prototype must come from glibc headers.

Thanks Sean and Jason.

It fixed the warnings, I'll send proper patch tomorrow once I'll be at
the office.

diff --git a/librdmacm/preload.c b/librdmacm/preload.c
index dfc23648..3ed0242e 100644
--- a/librdmacm/preload.c
+++ b/librdmacm/preload.c
@@ -51,6 +51,8 @@
 #include <stdlib.h>
 #include <stdio.h>

+#include <sys/uio.h>
+
 #include <rdma/rdma_cma.h>
 #include <rdma/rdma_verbs.h>
 #include <rdma/rsocket.h>

Thanks

>
> Jason
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