[PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Christophe Leroy]

When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
following build failure is encoutered:

In file included from arch/powerpc/mm/fault.c:33:0:
./include/linux/hugetlb.h: In function 'hstate_inode':
./include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
  return HUGETLBFS_SB(i->i_sb)->hstate;
         ^
./include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
  return HUGETLBFS_SB(i->i_sb)->hstate;
                              ^

Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.

Reported-by: kbuild test robot <lkp@intel.com>
Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 include/linux/hugetlb.h | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 1e897e4168ac..dafb3d70ff81 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -390,7 +390,10 @@ static inline bool is_file_hugepages(struct file *file)
 	return is_file_shm_hugepages(file);
 }
 
-
+static inline struct hstate *hstate_inode(struct inode *i)
+{
+	return HUGETLBFS_SB(i->i_sb)->hstate;
+}
 #else /* !CONFIG_HUGETLBFS */
 
 #define is_file_hugepages(file)			false
@@ -402,6 +405,10 @@ hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
 	return ERR_PTR(-ENOSYS);
 }
 
+static inline struct hstate *hstate_inode(struct inode *i)
+{
+	return NULL;
+}
 #endif /* !CONFIG_HUGETLBFS */
 
 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
@@ -472,11 +479,6 @@ extern unsigned int default_hstate_idx;
 
 #define default_hstate (hstates[default_hstate_idx])
 
-static inline struct hstate *hstate_inode(struct inode *i)
-{
-	return HUGETLBFS_SB(i->i_sb)->hstate;
-}
-
 static inline struct hstate *hstate_file(struct file *f)
 {
 	return hstate_inode(file_inode(f));
@@ -729,11 +731,6 @@ static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
 	return NULL;
 }
 
-static inline struct hstate *hstate_inode(struct inode *i)
-{
-	return NULL;
-}
-
 static inline struct hstate *page_hstate(struct page *page)
 {
 	return NULL;
-- 
2.25.0

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Baoquan He]

On 03/17/20 at 08:04am, Christophe Leroy wrote:
> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
> following build failure is encoutered:

From the definition of HUGETLB_PAGE, isn't it relying on HUGETLBFS?
I could misunderstand the def_bool, please correct me if I am wrong.

config HUGETLB_PAGE
        def_bool HUGETLBFS

> 
> In file included from arch/powerpc/mm/fault.c:33:0:
> ./include/linux/hugetlb.h: In function 'hstate_inode':
> ./include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>          ^
> ./include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>                               ^
> 
> Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
> Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
> Cc: stable@vger.kernel.org
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
>  include/linux/hugetlb.h | 19 ++++++++-----------
>  1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 1e897e4168ac..dafb3d70ff81 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -390,7 +390,10 @@ static inline bool is_file_hugepages(struct file *file)
>  	return is_file_shm_hugepages(file);
>  }
>  
> -
> +static inline struct hstate *hstate_inode(struct inode *i)
> +{
> +	return HUGETLBFS_SB(i->i_sb)->hstate;
> +}
>  #else /* !CONFIG_HUGETLBFS */
>  
>  #define is_file_hugepages(file)			false
> @@ -402,6 +405,10 @@ hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
>  	return ERR_PTR(-ENOSYS);
>  }
>  
> +static inline struct hstate *hstate_inode(struct inode *i)
> +{
> +	return NULL;
> +}
>  #endif /* !CONFIG_HUGETLBFS */
>  
>  #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
> @@ -472,11 +479,6 @@ extern unsigned int default_hstate_idx;
>  
>  #define default_hstate (hstates[default_hstate_idx])
>  
> -static inline struct hstate *hstate_inode(struct inode *i)
> -{
> -	return HUGETLBFS_SB(i->i_sb)->hstate;
> -}
> -
>  static inline struct hstate *hstate_file(struct file *f)
>  {
>  	return hstate_inode(file_inode(f));
> @@ -729,11 +731,6 @@ static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
>  	return NULL;
>  }
>  
> -static inline struct hstate *hstate_inode(struct inode *i)
> -{
> -	return NULL;
> -}
> -
>  static inline struct hstate *page_hstate(struct page *page)
>  {
>  	return NULL;
> -- 
> 2.25.0
> 
> 

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Christophe Leroy]

Le 17/03/2020 à 09:25, Baoquan He a écrit :
> On 03/17/20 at 08:04am, Christophe Leroy wrote:
>> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
>> following build failure is encoutered:
> 
>  From the definition of HUGETLB_PAGE, isn't it relying on HUGETLBFS?
> I could misunderstand the def_bool, please correct me if I am wrong.

AFAIU, it means that HUGETLBFS rely on HUGETLB_PAGE, by default 
HUGETLB_PAGE is not selected when HUGETLBFS is not. But it is still 
possible for an arch to select HUGETLB_PAGE without selecting HUGETLBFS 
when it uses huge pages for other purpose than hugetlb file system.

Christophe

> 
> config HUGETLB_PAGE
>          def_bool HUGETLBFS
> 
>>
>> In file included from arch/powerpc/mm/fault.c:33:0:
>> ./include/linux/hugetlb.h: In function 'hstate_inode':
>> ./include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
>>    return HUGETLBFS_SB(i->i_sb)->hstate;
>>           ^
>> ./include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
>>    return HUGETLBFS_SB(i->i_sb)->hstate;
>>                                ^
>>
>> Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.
>>
>> Reported-by: kbuild test robot <lkp@intel.com>
>> Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
>> Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>> ---
>>   include/linux/hugetlb.h | 19 ++++++++-----------
>>   1 file changed, 8 insertions(+), 11 deletions(-)
>>
>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>> index 1e897e4168ac..dafb3d70ff81 100644
>> --- a/include/linux/hugetlb.h
>> +++ b/include/linux/hugetlb.h
>> @@ -390,7 +390,10 @@ static inline bool is_file_hugepages(struct file *file)
>>   	return is_file_shm_hugepages(file);
>>   }
>>   
>> -
>> +static inline struct hstate *hstate_inode(struct inode *i)
>> +{
>> +	return HUGETLBFS_SB(i->i_sb)->hstate;
>> +}
>>   #else /* !CONFIG_HUGETLBFS */
>>   
>>   #define is_file_hugepages(file)			false
>> @@ -402,6 +405,10 @@ hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
>>   	return ERR_PTR(-ENOSYS);
>>   }
>>   
>> +static inline struct hstate *hstate_inode(struct inode *i)
>> +{
>> +	return NULL;
>> +}
>>   #endif /* !CONFIG_HUGETLBFS */
>>   
>>   #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
>> @@ -472,11 +479,6 @@ extern unsigned int default_hstate_idx;
>>   
>>   #define default_hstate (hstates[default_hstate_idx])
>>   
>> -static inline struct hstate *hstate_inode(struct inode *i)
>> -{
>> -	return HUGETLBFS_SB(i->i_sb)->hstate;
>> -}
>> -
>>   static inline struct hstate *hstate_file(struct file *f)
>>   {
>>   	return hstate_inode(file_inode(f));
>> @@ -729,11 +731,6 @@ static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
>>   	return NULL;
>>   }
>>   
>> -static inline struct hstate *hstate_inode(struct inode *i)
>> -{
>> -	return NULL;
>> -}
>> -
>>   static inline struct hstate *page_hstate(struct page *page)
>>   {
>>   	return NULL;
>> -- 
>> 2.25.0
>>
>>

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Mike Kravetz]

On 3/17/20 1:43 AM, Christophe Leroy wrote:
> 
> 
> Le 17/03/2020 à 09:25, Baoquan He a écrit :
>> On 03/17/20 at 08:04am, Christophe Leroy wrote:
>>> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
>>> following build failure is encoutered:
>>
>>  From the definition of HUGETLB_PAGE, isn't it relying on HUGETLBFS?
>> I could misunderstand the def_bool, please correct me if I am wrong.
> 
> AFAIU, it means that HUGETLBFS rely on HUGETLB_PAGE, by default HUGETLB_PAGE is not selected when HUGETLBFS is not. But it is still possible for an arch to select HUGETLB_PAGE without selecting HUGETLBFS when it uses huge pages for other purpose than hugetlb file system.
> 

Hi Christophe,

Do you actually have a use case/example of using hugetlb pages without
hugetlbfs?  I can understand that there are some use cases which never
use the filesystem interface.  However, hugetlb support is so intertwined
with hugetlbfs, I am thinking there would be issues trying to use them
separately.  I will look into this further.

-- 
Mike Kravetz

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Christophe Leroy]

Le 17/03/2020 à 17:40, Mike Kravetz a écrit :
> On 3/17/20 1:43 AM, Christophe Leroy wrote:
>>
>>
>> Le 17/03/2020 à 09:25, Baoquan He a écrit :
>>> On 03/17/20 at 08:04am, Christophe Leroy wrote:
>>>> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
>>>> following build failure is encoutered:
>>>
>>>   From the definition of HUGETLB_PAGE, isn't it relying on HUGETLBFS?
>>> I could misunderstand the def_bool, please correct me if I am wrong.
>>
>> AFAIU, it means that HUGETLBFS rely on HUGETLB_PAGE, by default HUGETLB_PAGE is not selected when HUGETLBFS is not. But it is still possible for an arch to select HUGETLB_PAGE without selecting HUGETLBFS when it uses huge pages for other purpose than hugetlb file system.
>>
> 
> Hi Christophe,
> 
> Do you actually have a use case/example of using hugetlb pages without
> hugetlbfs?  I can understand that there are some use cases which never
> use the filesystem interface.  However, hugetlb support is so intertwined
> with hugetlbfs, I am thinking there would be issues trying to use them
> separately.  I will look into this further.
> 

Hi Mike,

Series https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=164620

And especially patch 39 to 41.

Thanks
Christophe

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Mike Kravetz]

On 3/17/20 9:47 AM, Christophe Leroy wrote:
> 
> 
> Le 17/03/2020 à 17:40, Mike Kravetz a écrit :
>> On 3/17/20 1:43 AM, Christophe Leroy wrote:
>>>
>>>
>>> Le 17/03/2020 à 09:25, Baoquan He a écrit :
>>>> On 03/17/20 at 08:04am, Christophe Leroy wrote:
>>>>> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
>>>>> following build failure is encoutered:
>>>>
>>>>   From the definition of HUGETLB_PAGE, isn't it relying on HUGETLBFS?
>>>> I could misunderstand the def_bool, please correct me if I am wrong.
>>>
>>> AFAIU, it means that HUGETLBFS rely on HUGETLB_PAGE, by default HUGETLB_PAGE is not selected when HUGETLBFS is not. But it is still possible for an arch to select HUGETLB_PAGE without selecting HUGETLBFS when it uses huge pages for other purpose than hugetlb file system.
>>>
>>
>> Hi Christophe,
>>
>> Do you actually have a use case/example of using hugetlb pages without
>> hugetlbfs?  I can understand that there are some use cases which never
>> use the filesystem interface.  However, hugetlb support is so intertwined
>> with hugetlbfs, I am thinking there would be issues trying to use them
>> separately.  I will look into this further.
>>
> 
> Hi Mike,
> 
> Series https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=164620
> 
> And especially patch 39 to 41.
> 

Ah, ok.  You are simply using a few interfaces in the hugetlb header files.
The huge pages created in your mappings are not PageHuge() pages.

-- 
Mike Kravetz

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Mike Kravetz]

On 3/17/20 1:04 AM, Christophe Leroy wrote:
> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
> following build failure is encoutered:
> 
> In file included from arch/powerpc/mm/fault.c:33:0:
> ./include/linux/hugetlb.h: In function 'hstate_inode':
> ./include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>          ^
> ./include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>                               ^
> 
> Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
> Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
> Cc: stable@vger.kernel.org
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

As hugetlb.h evolved over time, I suspect nobody imagined a configuration
with CONFIG_HUGETLB_PAGE and not CONFIG_HUGETLBFS.  This patch does address
the build issues.  So,

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

However, there are many definitions in that file not behind #ifdef
CONFIG_HUGETLBFS that make no sense unless CONFIG_HUGETLBFS is defined.
Such cleanup is way beyond the scope of this patch/effort.  I will add
it to the list of hugetlb/hugetlbfs things that can be cleaned up.
-- 
Mike Kravetz

Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not HUGEBTLBFS

[Andrew Morton]

On Tue, 17 Mar 2020 08:04:14 +0000 (UTC) Christophe Leroy <christophe.leroy@c-s.fr> wrote:

> When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the
> following build failure is encoutered:
> 
> In file included from arch/powerpc/mm/fault.c:33:0:
> ./include/linux/hugetlb.h: In function 'hstate_inode':
> ./include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>          ^
> ./include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
>   return HUGETLBFS_SB(i->i_sb)->hstate;
>                               ^
> 
> Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
> Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")

A 12 year old build error?  If accurate, that has to be a world record.

> Cc: stable@vger.kernel.org

I think I'll remove this.  Obviously nobody is suffering from this problem!