[PATCH] Fix compilation warnings in usr/kernel code

[Erez Zilber]

Fix compilation warnings and modify the Makefiles to treat
warnings as errors.

Signed-off-by: Erez Zilber <erezz...@gmail.com>

[Erez Zilber]

2 comments about this patch:
1. I'm not familiar enough with the fwparam_ibft code, so I didn't add
the -Werror flag to the Makefile. There are still compilation warnings
in that code.
2. I was able to test it on CentOS 5.3 & kubuntu 9.04 only. If anyone
can test it on other kernels and submit fixes, it would be great.

Erez

[Mike Christie]

Thanks.

I get this compilation error on fedora 10. We used to get a warning about it not being initialized and upstream we did this patch. Is this just a bug in my compiler?

@@ -693,6 +692,7 @@ int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
"Too many iscsi targets. Max "
"number of targets is %d.\n",
ISCSI_MAX_TARGET - 1);
+ err = -EOVERFLOW;
goto release_host;
}
}

make
make -C /lib/modules/2.6.29.4-167.fc11.x86_64/build M=`pwd` KBUILD_OUTPUT= V=0 modules
make[1]: Entering directory `/usr/src/kernels/2.6.29.4-167.fc11.x86_64'
CC [M] /home/mnc/kernel/iscsi/open-iscsi/devel/open-iscsi/kernel/scsi_transport_iscsi.o
cc1: warnings being treated as errors
/home/mnc/kernel/iscsi/open-iscsi/devel/open-iscsi/kernel/scsi_transport_iscsi.c: In function ‘iscsi_add_session’:
/home/mnc/kernel/iscsi/open-iscsi/devel/open-iscsi/kernel/scsi_transport_iscsi.c:678: error: ‘err’ may be used uninitialized in this function
make[2]: *** [/home/mnc/kernel/iscsi/open-iscsi/devel/open-iscsi/kernel/scsi_transport_iscsi.o] Error 1
make[1]: *** [_module_/home/mnc/kernel/iscsi/open-iscsi/devel/open-iscsi/kernel] Error 2
make[1]: Leaving directory `/usr/src/kernels/2.6.29.4-167.fc11.x86_64'

[Erez Zilber]

Yeah, this looks strange because err should have been initialized in
the for loop (assuming that ISCSI_MAX_TARGET > 0). Maybe the compiler
doesn't check that (which may be considered a bug/feature ;) ). Do you
want to add this fix also to open-iscsi.git?

Erez

[Ulrich Windl]

On 6 Sep 2009 at 10:11, Erez Zilber wrote:

> Yeah, this looks strange because err should have been initialized in
> the for loop (assuming that ISCSI_MAX_TARGET > 0). Maybe the compiler
> doesn't check that (which may be considered a bug/feature ;) ). Do you
> want to add this fix also to open-iscsi.git?

Yes, there are some situations where gcc does not detect that a variable is
initialized. However in most cases gcc is right.

Ulrich

[Boaz Harrosh]

On 09/03/2009 08:02 PM, Mike Christie wrote:
>
> On 09/03/2009 11:21 AM, Erez Zilber wrote:
>> Fix compilation warnings and modify the Makefiles to treat
>> warnings as errors.
>>
>> Signed-off-by: Erez Zilber <erezz...@gmail.com>
>>
>
>
> Thanks.
>
>
> I get this compilation error on fedora 10. We used to get a warning about it not being initialized and upstream we did this patch. Is this just a bug in my compiler?
>
>
> @@ -693,6 +692,7 @@ int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
> "Too many iscsi targets. Max "
> "number of targets is %d.\n",
> ISCSI_MAX_TARGET - 1);
> + err = -EOVERFLOW;

Better use the uninitialized_var() macro on declaration of variable.
1. It does not produce any code in shutting up the warning.
2. There is a scrip laying around that turns the macro off and looks for warning instances
for every uninitialized_var use. So in the future this can be removed when the compilers
we care about stop to complain.
3. Better Programmer's communication of what's up.

Boaz

[Mike Christie]

I messed up. I thought we already had the fix, so I was wondering why I
get the compilation error with your patch. I mean I thought your patch
added a new failure somehow. Ignore me :)

[Erez Zilber]

OK, so do you want to apply my patch as is + the required fix in
iscsi_add_session?

Erez

[Mike Christie]

Yeah, I was going to apply the iscsi_add_session fix (I was acutally
working on resyncing all the upstream code that was sent for 2.6.32 and
2.6.31 with the open-iscsi/kernel stuff) then your patch.

[Mike Christie]

Erez Zilber wrote:
> Fix compilation warnings and modify the Makefiles to treat
> warnings as errors.
>

Just a update on this patch. I was doing more testing and on Fedora 9, I
get:

isns.c: In function ‘build_dev_reg_req’:
isns.c:146: error: dereferencing pointer ‘lss.24’ does break
strict-aliasing rules
isns.c:146: note: initialized from here
isns.c:153: error: dereferencing pointer ‘lss.24’ does break
strict-aliasing rules
isns.c:153: note: initialized from here
isns.c:157: error: dereferencing pointer ‘lss.27’ does break
strict-aliasing rules
isns.c:157: note: initialized from here
make[1]: *** [isns.o] Error 1
make[1]: Leaving directory
`/home/mnc/kernel/iscsi/open-iscsi/devel/tmp/open-iscsi/usr'