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    Subject[PATCH v6 65/99] dax: Fix sparse warning
    Date
    From: Matthew Wilcox <mawilcox@microsoft.com>

    sparse doesn't know that follow_pte_pmd() conditionally acquires the ptl,
    because it's in a separate compilation unit. Move follow_pte_pmd() to
    mm.h where sparse can see it.

    Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
    ---
    include/linux/mm.h | 15 ++++++++++++++-
    mm/memory.c | 16 +---------------
    2 files changed, 15 insertions(+), 16 deletions(-)

    diff --git a/include/linux/mm.h b/include/linux/mm.h
    index fe1ee4313add..9c384c486edf 100644
    --- a/include/linux/mm.h
    +++ b/include/linux/mm.h
    @@ -1314,7 +1314,7 @@ int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
    struct vm_area_struct *vma);
    void unmap_mapping_range(struct address_space *mapping,
    loff_t const holebegin, loff_t const holelen, int even_cows);
    -int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    +int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    unsigned long *start, unsigned long *end,
    pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
    int follow_pfn(struct vm_area_struct *vma, unsigned long address,
    @@ -1324,6 +1324,19 @@ int follow_phys(struct vm_area_struct *vma, unsigned long address,
    int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
    void *buf, int len, int write);

    +static inline int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    + unsigned long *start, unsigned long *end,
    + pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
    +{
    + int res;
    +
    + /* (void) is needed to make gcc happy */
    + (void) __cond_lock(*ptlp,
    + !(res = __follow_pte_pmd(mm, address, start, end,
    + ptepp, pmdpp, ptlp)));
    + return res;
    +}
    +
    static inline void unmap_shared_mapping_range(struct address_space *mapping,
    loff_t const holebegin, loff_t const holelen)
    {
    diff --git a/mm/memory.c b/mm/memory.c
    index ca5674cbaff2..66184601ac03 100644
    --- a/mm/memory.c
    +++ b/mm/memory.c
    @@ -4201,7 +4201,7 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
    }
    #endif /* __PAGETABLE_PMD_FOLDED */

    -static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    +int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    unsigned long *start, unsigned long *end,
    pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
    {
    @@ -4278,20 +4278,6 @@ static inline int follow_pte(struct mm_struct *mm, unsigned long address,
    return res;
    }

    -int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
    - unsigned long *start, unsigned long *end,
    - pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
    -{
    - int res;
    -
    - /* (void) is needed to make gcc happy */
    - (void) __cond_lock(*ptlp,
    - !(res = __follow_pte_pmd(mm, address, start, end,
    - ptepp, pmdpp, ptlp)));
    - return res;
    -}
    -EXPORT_SYMBOL(follow_pte_pmd);
    -
    /**
    * follow_pfn - look up PFN at a user virtual address
    * @vma: memory mapping
    --
    2.15.1
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