diff options
author | Stefan Agner <stefan@agner.ch> | 2017-03-14 13:59:28 -0700 |
---|---|---|
committer | Max Krummenacher <max.krummenacher@toradex.com> | 2017-03-15 18:35:51 +0100 |
commit | 39ac0033f2345ce7b5d8ca4439192407dacb2355 (patch) | |
tree | 51dc588baa63d31bc406388885f62c1cae068fa3 /mm/gup.c | |
parent | 13f2767f31803754aa883f298737aff866f04628 (diff) | |
parent | d9e0350d2575a20ee7783427da9bd6b6107eb983 (diff) |
Merge tag 'v4.1.39' into toradex_vf_4.1-nexttoradex_vf_4.1
Linux 4.1.39
Diffstat (limited to 'mm/gup.c')
-rw-r--r-- | mm/gup.c | 14 |
1 files changed, 12 insertions, 2 deletions
@@ -32,6 +32,16 @@ static struct page *no_page_table(struct vm_area_struct *vma, return NULL; } +/* + * FOLL_FORCE can write to even unwritable pte's, but only + * after we've gone through a COW cycle and they are dirty. + */ +static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) +{ + return pte_write(pte) || + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); +} + static struct page *follow_page_pte(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, unsigned int flags) { @@ -66,7 +76,7 @@ retry: } if ((flags & FOLL_NUMA) && pte_protnone(pte)) goto no_page; - if ((flags & FOLL_WRITE) && !pte_write(pte)) { + if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) { pte_unmap_unlock(ptep, ptl); return NULL; } @@ -315,7 +325,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, * reCOWed by userspace write). */ if ((ret & VM_FAULT_WRITE) && !(vma->vm_flags & VM_WRITE)) - *flags &= ~FOLL_WRITE; + *flags |= FOLL_COW; return 0; } |