On Thu, Apr 06 2017, Jes Sorensen wrote:

> On 04/06/2017 04:21 AM, Liu Zhilong wrote:
>> hi,
>>
>> I found this compiling warning, and can reproduce on my Leap42.1,
>> Leap42.2 and SLES12 SP2 with v4.8.5 version of gcc.
>>
>> # gcc -v
>> Using built-in specs.
>> COLLECT_GCC=gcc
>> COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/4.8/lto-wrapper
>> Target: x86_64-suse-linux
>> Configured with: ../configure --prefix=/usr --infodir=/usr/share/info
>> --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64
>> --enable-languages=c,c++,objc,fortran,obj-c++,java,ada
>> --enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.8
>> --enable-ssp --disable-libssp --disable-plugin
>> --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux'
>> --disable-libgcj --disable-libmudflap --with-slibdir=/lib64
>> --with-system-zlib --enable-__cxa_atexit
>> --enable-libstdcxx-allocator=new --disable-libstdcxx-pch
>> --enable-version-specific-runtime-libs --enable-linker-build-id
>> --enable-linux-futex --program-suffix=-4.8 --without-system-libunwind
>> --with-arch-32=i586 --with-tune=generic --build=x86_64-suse-linux
>> --host=x86_64-suse-linux
>> Thread model: posix
>> gcc version 4.8.5 (SUSE Linux)
>>
>> # make everything
>> ... ...
>> mdadm.c: In function ‘main’:
>> mdadm.c:1974:29: error: ‘mdfd’ may be used uninitialized in this
>> function [-Werror=maybe-uninitialized]
>>    if (dv->devname[0] == '/' || mdfd < 0)
>>                              ^
>> mdadm.c:1914:7: note: ‘mdfd’ was declared here
>>    int mdfd;
>>        ^
>> cc1: all warnings being treated as errors
>> Makefile:206: recipe for target 'mdadm.Os' failed
>> make: *** [mdadm.Os] Error 1
>
> Crappy compiler, you're running an old gcc. But sure, send me a patch 
> that initializes mdfd to -1.

I would rather make the code more obviously correct.

		if (dv->devname[0] == '/' ||
		    (mdfd = open_dev(dv->devname)) < 0)
			mdfd = open_mddev(dv->devname, 1);

well... it is more obvious to me.

NeilBrown