[PATCH] powerpc32: fix warning from include/linux/mm.h

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE4172d

5 messages, 3 authors, 2015-04-08 · open the first message on its own page

[PATCH] powerpc32: fix warning from include/linux/mm.h

From: Christophe Leroy <hidden>
Date: 2014-12-05 11:20:29

include/linux/mm.h: In function 'is_vmalloc_addr':
include/linux/mm.h:367:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  return addr >= VMALLOC_START && addr < VMALLOC_END;
              ^

Signed-off-by: Christophe Leroy <redacted>

---
 arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 234e07c..543bb8e 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -92,7 +92,7 @@ extern int icache_44x_need_flush;
  * system.  This really does become a problem for machines with good amounts
  * of RAM.  -- Cort
  */
-#define VMALLOC_OFFSET (0x1000000) /* 16M */
+#define VMALLOC_OFFSET (0x1000000U) /* 16M */
 #ifdef PPC_PIN_SIZE
 #define VMALLOC_START (((_ALIGN((long)high_memory, PPC_PIN_SIZE) + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
 #else
-- 
2.1.0

Re: powerpc32: fix warning from include/linux/mm.h

From: Scott Wood <hidden>
Date: 2015-03-20 23:52:26

On Fri, Dec 05, 2014 at 12:20:20PM +0100, LEROY Christophe wrote:
include/linux/mm.h: In function 'is_vmalloc_addr':
include/linux/mm.h:367:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  return addr >= VMALLOC_START && addr < VMALLOC_END;
              ^

Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
That warning doesn't appear to be enabled.  What config are you seeing
this with?

I'm also not clear on why this was assigned to me in patchwork.

-Scott

Re: powerpc32: fix warning from include/linux/mm.h

From: leroy christophe <hidden>
Date: 2015-04-07 08:08:19

Le 21/03/2015 00:52, Scott Wood a écrit :
On Fri, Dec 05, 2014 at 12:20:20PM +0100, LEROY Christophe wrote:
quoted
include/linux/mm.h: In function 'is_vmalloc_addr':
include/linux/mm.h:367:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   return addr >= VMALLOC_START && addr < VMALLOC_END;
               ^

Signed-off-by: Christophe Leroy <redacted>
---
  arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
That warning doesn't appear to be enabled.  What config are you seeing
this with?
I'm used to adding EXTRA_CFLAGS=-Wextra  when checking my own drivers, 
as it helps finding additional bugs.

When doing that, the only warnings I get outside of my own code are this 
one, and the other one in my proposed patch identified "powerpc32: fix 
warning from include/asm-generic/termios-base.h"

I though it would be worth fixing those two warnings in order to get a 
perfectly clean code.

Christophe

Re: powerpc32: fix warning from include/linux/mm.h

From: Scott Wood <hidden>
Date: 2015-04-07 21:20:05

On Tue, 2015-04-07 at 10:07 +0200, leroy christophe wrote:
Le 21/03/2015 00:52, Scott Wood a écrit :
quoted
On Fri, Dec 05, 2014 at 12:20:20PM +0100, LEROY Christophe wrote:
quoted
include/linux/mm.h: In function 'is_vmalloc_addr':
include/linux/mm.h:367:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   return addr >= VMALLOC_START && addr < VMALLOC_END;
               ^

Signed-off-by: Christophe Leroy <redacted>
---
  arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
That warning doesn't appear to be enabled.  What config are you seeing
this with?
I'm used to adding EXTRA_CFLAGS=-Wextra  when checking my own drivers, 
as it helps finding additional bugs.
It also produces a lot of noise, which is why Linux doesn't enable it.
E.g. it enables useless "unused parameter" warnings all over the place.
When doing that, the only warnings I get outside of my own code are this 
one, and the other one in my proposed patch identified "powerpc32: fix 
warning from include/asm-generic/termios-base.h"

I though it would be worth fixing those two warnings in order to get a 
perfectly clean code.
In general I don't think we should clutter up the code with suppression
for warnings we don't enable, but in this case we do end up with a value
that would be negative if considered as signed.  Instead of changing
VMALLOC_OFFSET, though, I'd address it where the problem is actually
introduced -- which is casting high_memory to (long) rather than
(unsigned long) or (uintptr_t).

-Scott

Re: powerpc32: fix warning from include/linux/mm.h

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2015-04-08 03:27:25

On Fri, 2015-03-20 at 18:52 -0500, Scott Wood wrote:
On Fri, Dec 05, 2014 at 12:20:20PM +0100, LEROY Christophe wrote:
quoted
include/linux/mm.h: In function 'is_vmalloc_addr':
include/linux/mm.h:367:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  return addr >= VMALLOC_START && addr < VMALLOC_END;
              ^

Signed-off-by: Christophe Leroy <redacted>
---
 arch/powerpc/include/asm/pgtable-ppc32.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
That warning doesn't appear to be enabled.  What config are you seeing
this with?

I'm also not clear on why this was assigned to me in patchwork.
Because it's from Christophe.

cheers
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