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 <l...@intel.com>
Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
Fixes: a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
Cc: sta...@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.le...@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