Re: [PATCH v7 13/13] xen: introduce a Kconfig option to enable the pvcalls frontend

[Boris Ostrovsky]

On 10/30/2017 03:48 PM, Stefano Stabellini wrote:
> On Mon, 30 Oct 2017, Boris Ostrovsky wrote:
>>
>> Build warnings (gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1))
> Hi Boris, I am trying to repro the warnings below. I have been
> unsuccessful so far. What system are you using? Fedora? CentOS? Do have
> any specific CFLAGS settings?


I am on Fedora24, nothing interesting in my environment. For example,

ostr@workbase> env | grep FLAGS
ostr@workbase>

I'll send you my config file in a separate email, just in case.  Your
patches are on top of

    0b07194 Linux 4.14-rc7

ostr@workbase> gcc -Wp,-MD,drivers/xen/.pvcalls-front.o.d  -nostdinc
-isystem /usr/lib/gcc/x86_64-redhat-linux/6.3.1/include
-I/data/upstream/linux-xen/arch/x86/include
-I./arch/x86/include/generated  -I/data/upstream/linux-xen/include
-I./include -I/data/upstream/linux-xen/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi
-I/data/upstream/linux-xen/include/uapi -I./include/generated/uapi
-include /data/upstream/linux-xen/include/linux/kconfig.h 
-I/data/upstream/linux-xen/drivers/xen -Idrivers/xen -D__KERNEL__ -Wall
-Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing
-fno-common -fshort-wchar -Werror-implicit-function-declaration
-Wno-format-security -std=gnu89 -fno-PIE -mno-sse -mno-mmx -mno-sse2
-mno-3dnow -mno-avx -m64 -falign-jumps=1 -falign-loops=1 -mno-80387
-mno-fp-ret-in-387 -mpreferred-stack-boundary=3 -mskip-rax-setup
-mtune=generic -mno-red-zone -mcmodel=kernel -funit-at-a-time
-DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1
-DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -DCONFIG_AS_SSSE3=1
-DCONFIG_AS_CRC32=1 -DCONFIG_AS_AVX=1 -DCONFIG_AS_AVX2=1
-DCONFIG_AS_AVX512=1 -DCONFIG_AS_SHA1_NI=1 -DCONFIG_AS_SHA256_NI=1 -pipe
-Wno-sign-compare -fno-asynchronous-unwind-tables
-fno-delete-null-pointer-checks -Wno-frame-address -O2
--param=allow-store-data-races=0 -DCC_HAVE_ASM_GOTO
-Wframe-larger-than=2048 -fstack-protector-strong
-Wno-unused-but-set-variable -Wno-unused-const-variable
-fno-omit-frame-pointer -fno-optimize-sibling-calls
-fno-var-tracking-assignments -g -pg -mfentry -DCC_USING_FENTRY
-Wdeclaration-after-statement -Wno-pointer-sign -fno-strict-overflow
-fconserve-stack -Werror=implicit-int -Werror=strict-prototypes
-Werror=date-time -Werror=incompatible-pointer-types
-Werror=designated-init  -DMODULE  -DKBUILD_BASENAME='"pvcalls_front"' 
-DKBUILD_MODNAME='"pvcalls_front"' -c -o drivers/xen/pvcalls-front.o
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c: In function
â__write_ringâ:
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:459:3: warning:
ignoring return value of âcopy_from_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
   copy_from_iter(data->out + masked_prod, len, msg_iter);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:462:4: warning:
ignoring return value of âcopy_from_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_from_iter(data->out + masked_prod,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            array_size - masked_prod, msg_iter);
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:464:4: warning:
ignoring return value of âcopy_from_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_from_iter(data->out,
    ^~~~~~~~~~~~~~~~~~~~~~~~~
            len - (array_size - masked_prod),
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            msg_iter);
            ~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:468:4: warning:
ignoring return value of âcopy_from_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_from_iter(data->out + masked_prod, len, msg_iter);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c: In function
â__read_ringâ:
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:560:3: warning:
ignoring return value of âcopy_to_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
   copy_to_iter(data->in + masked_cons, len, msg_iter);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:563:4: warning:
ignoring return value of âcopy_to_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_to_iter(data->in + masked_cons,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          array_size - masked_cons, msg_iter);
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:565:4: warning:
ignoring return value of âcopy_to_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_to_iter(data->in,
    ^~~~~~~~~~~~~~~~~~~~~~
          len - (array_size - masked_cons),
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          msg_iter);
          ~~~~~~~~~
/data/upstream/linux-xen/drivers/xen/pvcalls-front.c:569:4: warning:
ignoring return value of âcopy_to_iterâ, declared with attribute
warn_unused_result [-Wunused-result]
    copy_to_iter(data->in + masked_cons, len, msg_iter);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ostr@workbase>