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Date:   Tue, 17 Mar 2020 16:25:50 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     Mike Kravetz <mike.kravetz@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nishanth Aravamudan <nacc@us.ibm.com>,
        Nick Piggin <npiggin@suse.de>, Adam Litke <agl@us.ibm.com>,
        Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm/hugetlb: Fix build failure with HUGETLB_PAGE but not
 HUGEBTLBFS
Message-ID: <20200317082550.GA3375@MiWiFi-R3L-srv>
References: <7e8c3a3c9a587b9cd8a2f146df32a421b961f3a2.1584432148.git.christophe.leroy@c-s.fr>
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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
> 
>