assert_spin_locked(pmd_lockptr(mm, pmd));
+ /*
+ * When we COW a devmap PMD entry, we split it into PTEs, so we should
+ * not be in this function with `flags & FOLL_COW` set.
+ */
+ WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
+
if (flags & FOLL_WRITE && !pmd_write(*pmd))
return NULL;
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,
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 */
}
/* See similar comment in do_numa_page for explanation */
- if (!pmd_write(pmd))
+ if (!pmd_savedwrite(pmd))
flags |= TNF_NO_GROUP;
/*
goto out;
clear_pmdnuma:
BUG_ON(!PageLocked(page));
- was_writable = pmd_write(pmd);
+ was_writable = pmd_savedwrite(pmd);
pmd = pmd_modify(pmd, vma->vm_page_prot);
pmd = pmd_mkyoung(pmd);
if (was_writable)
if (page_nid != -1)
task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR,
- vmf->flags);
+ flags);
return 0;
}
deactivate_page(page);
if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
- orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
- tlb->fullmm);
+ pmdp_invalidate(vma, addr, pmd);
orig_pmd = pmd_mkold(orig_pmd);
orig_pmd = pmd_mkclean(orig_pmd);
entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd);
entry = pmd_modify(entry, newprot);
if (preserve_write)
- entry = pmd_mkwrite(entry);
+ entry = pmd_mk_savedwrite(entry);
ret = HPAGE_PMD_NR;
set_pmd_at(mm, addr, pmd, entry);
BUG_ON(vma_is_anonymous(vma) && !preserve_write &&