On Tue, 2017-12-19 at 08:58 -0800, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
>
> The one user of follow_pte_pmd (dax) emits a sparse warning because
> it doesn't know that follow_pte_pmd conditionally returns with the
> pte/pmd locked. The required annotation is already there; it's just
> in the wrong file.
[]
> diff --git a/include/linux/mm.h b/include/linux/mm.h
[]
> @@ -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)));
This seems obscure and difficult to read. Perhaps:
res = __follow_pte_pmd(mm, address, start, end, ptepp, pmdpp, ptlp);
(void)__cond_lock(*ptlp, !res);
> + return res;
> +}
--
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