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| author | Alex Shi <alex.shi@linaro.org> | 2017-05-26 12:02:47 +0800 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2017-05-26 12:02:47 +0800 |
| commit | 9d92a6ee405610ce9d250307d9c81807d1bdcc33 (patch) | |
| tree | eb880868b26441f9faa12d73b2d334f6f90ae217 /mm | |
| parent | d4a181a68ad99f0a819212f9fc09690707891325 (diff) | |
| parent | 6b65a8f64f4fd256ac0f6b9e97e9939ae18fc6c7 (diff) | |
Merge tag 'v3.18.55' into linux-linaro-lsk-v3.18
This is the 3.18.55 stable release
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2e39d4e0ff09..8c9cbd0e4f3f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1205,6 +1205,16 @@ out_unlock: return ret; } +/* + * FOLL_FORCE can write to even unwritable pmd's, but only + * after we've gone through a COW cycle and they are dirty. + */ +static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags) +{ + return pmd_write(pmd) || + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd)); +} + struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, @@ -1215,7 +1225,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, assert_spin_locked(pmd_lockptr(mm, pmd)); - if (flags & FOLL_WRITE && !pmd_write(*pmd)) + if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags)) goto out; /* Avoid dumping huge zero page */ |