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| author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2017-06-17 17:01:11 +0200 |
|---|---|---|
| committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2017-06-17 17:01:11 +0200 |
| commit | c1d5fe2d54551b95b812143d94d8168da2220dd8 (patch) | |
| tree | fdde4472ab2b19fcadaae22d68a0c9b008f74373 /mm/huge_memory.c | |
| parent | 0068a1b36d309f22698f7de7478b72e672360129 (diff) | |
| parent | 1bd30958ec55d80ca72d2ca4e7e5c3d9fbf3173e (diff) | |
Merge tag 'v4.4.73' into toradex_vf_4.4-nextColibri-VF_LXDE-Image_2.7b3-20170630
This is the 4.4.73 stable release
Diffstat (limited to 'mm/huge_memory.c')
| -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 530e6427f823..47b469663822 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1269,6 +1269,16 @@ 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, @@ -1279,7 +1289,7 @@ 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 */ |