On 11/08/2016 03:10 AM, Michael Ellerman wrote:
Hi Dmitry,

Thanks for the patches.

Dmitry Safonov <dsafo...@virtuozzo.com> writes:
Impact: cleanup

I'm not a fan of these "Impact" lines, especially when they're not
correct, ie. this is not a cleanup, a cleanup doesn't change logic.

Rename `rc' variable which doesn't seems to mean anything into
kernel-known `ret'.

'rc' means "Return Code", it's fairly common. I see at least ~8500
"int rc" declarations in the kernel.

Please don't rename variables and change logic in one patch.

Ok, right - just didn't saw `rc' that freq as `ret'.
Will leave the name.

Combine two function returns into one as it's
also easier to read.

Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux...@kvack.org
Signed-off-by: Dmitry Safonov <dsafo...@virtuozzo.com>
---
 arch/powerpc/kernel/vdso.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 4111d30badfa..4ffb82a2d9e9 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -154,7 +154,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
int uses_interp)
        struct page **vdso_pagelist;
        unsigned long vdso_pages;
        unsigned long vdso_base;
-       int rc;
+       int ret = 0;

Please don't initialise return codes in the declaration, it prevents the
compiler from warning you if you forget to initialise it in a
particular path.

AFAICS you never even use the default value either.

Oh, right - I split this patch from converting install_special_mapping()
to special vma version _install_special_mapping(), 6/8 patch in series.
Will move initialization to that patch.

        if (!vdso_ready)
                return 0;
@@ -203,8 +203,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, 
int uses_interp)
                                      ((VDSO_ALIGNMENT - 1) & PAGE_MASK),
                                      0, 0);
        if (IS_ERR_VALUE(vdso_base)) {
-               rc = vdso_base;
-               goto fail_mmapsem;
+               ret = vdso_base;
+               goto out_up_mmap_sem;
        }

        /* Add required alignment. */
@@ -227,21 +227,16 @@ int arch_setup_additional_pages(struct linux_binprm 
*bprm, int uses_interp)
         * It's fine to use that for setting breakpoints in the vDSO code
         * pages though.
         */
-       rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
+       ret = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
                                     VM_READ|VM_EXEC|
                                     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
                                     vdso_pagelist);
-       if (rc) {
+       if (ret)
                current->mm->context.vdso_base = 0;
-               goto fail_mmapsem;
-       }
-
-       up_write(&mm->mmap_sem);
-       return 0;

- fail_mmapsem:
+out_up_mmap_sem:
        up_write(&mm->mmap_sem);
-       return rc;
+       return ret;
 }


If you strip out the variable renames then I think that change would be
OK.

cheers



--
             Dmitry

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