From: Joao Martins <joao.m.martins@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: kernel test robot <lkp@intel.com>,
kbuild-all@lists.01.org, clang-built-linux@googlegroups.com,
Dan Williams <dan.j.williams@intel.com>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [linux-next:master 3165/3717] drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736 with expression of type 'unsigned int' is always false
Date: Fri, 28 Aug 2020 18:32:12 +0100 [thread overview]
Message-ID: <435778c3-65c2-7e5d-578d-68cf89ae19bd@oracle.com> (raw)
In-Reply-To: <202008280906.WPrik7QQ%lkp@intel.com>
On 8/28/20 2:01 AM, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head: 88abac0b753dfdd85362a26d2da8277cb1e0842b
> commit: f464f9a6a06f2f521f78a6e1ac8680bca2e929e4 [3165/3717] device-dax: add an 'align' attribute
> config: arm64-randconfig-r013-20200827 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 71f3169e1baeff262583b35ef88f8fb6df7be85e)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # install arm64 cross compiling tool for clang build
> # apt-get install binutils-aarch64-linux-gnu
> git checkout f464f9a6a06f2f521f78a6e1ac8680bca2e929e4
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> In file included from drivers/dax/super.c:18:
>>> drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736 with expression of type 'unsigned int' is always false [-Wtautological-constant-out-of-range-compare]
> if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
> ~~~~~ ^ ~~~~~~~~
> In file included from drivers/dax/bus.c:10:
>>> drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736 with expression of type 'unsigned int' is always false [-Wtautological-constant-out-of-range-compare]
> if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
> ~~~~~ ^ ~~~~~~~~
> 1 warning generated.
> --
> In file included from drivers/dax/device.c:14:
>>> drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736 with expression of type 'unsigned int' is always false [-Wtautological-constant-out-of-range-compare]
> if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
> ~~~~~ ^ ~~~~~~~~
Despite HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD being x86 only,
arm64 would still need the following fixup:
device-dax-add-an-align-attribute-fix.patch:
From: Joao Martins <joao.m.martins@oracle.com>
Date: Fri, 28 Aug 2020 11:33:14 -0400
Subject: [PATCH] device-dax: Fix dax_align_valid() to work on PAGE_SHIFT>=14
With ARM64_PAGE_SHIFT=14, we get:
In file included from drivers/dax/device.c:14:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
~~~~~ ^ ~~~~~~~~
In file included from drivers/dax/super.c:18:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
~~~~~ ^ ~~~~~~~~
In file included from drivers/dax/bus.c:10:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 68719476736
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
~~~~~ ^ ~~~~~~~~
Or with ARM64_PAGE_SHIFT=16 && ARM64_VA_BITS_52=y:
In file included from drivers/dax/device.c:14:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 4398046511104
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
~~~~~ ^ ~~~~~~~~
In file included from drivers/dax/super.c:18:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 4398046511104
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
In file included from drivers/dax/bus.c:10:
drivers/dax/dax-private.h:94:12: warning: result of comparison of constant 4398046511104
with expression of type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
~~~~~ ^ ~~~~~~~~
Change dax_align_valid() to unsigned long (dax_align_valid()
already is unsigned long). Note that in practice
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD is only set on x86,
so a dax_align_valid(PUD_SIZE) check always return false.
An alternative would be to invert the check to:
if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) && align == PUD_SIZE)
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Link: https://lore.kernel.org/linux-mm/202008280906.WPrik7QQ%25lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
drivers/dax/dax-private.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index fe337436d7f5..1c974b7caae6 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -89,7 +89,7 @@ static inline struct dax_mapping *to_dax_mapping(struct device *dev)
phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, unsigned long size);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static inline bool dax_align_valid(unsigned int align)
+static inline bool dax_align_valid(unsigned long align)
{
if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
return true;
@@ -100,7 +100,7 @@ static inline bool dax_align_valid(unsigned int align)
return false;
}
#else
-static inline bool dax_align_valid(unsigned int align)
+static inline bool dax_align_valid(unsigned long align)
{
return align == PAGE_SIZE;
}
--
2.17.1
prev parent reply other threads:[~2020-08-28 17:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-28 1:01 kernel test robot
2020-08-28 17:32 ` Joao Martins [this message]
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