diff options
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 30 |
1 files changed, 27 insertions, 3 deletions
@@ -390,6 +390,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, struct page *page; spinlock_t *ptl; pte_t *ptep, pte; + int ret; /* FOLL_GET and FOLL_PIN are mutually exclusive. */ if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == @@ -448,8 +449,6 @@ retry: if (is_zero_pfn(pte_pfn(pte))) { page = pte_page(pte); } else { - int ret; - ret = follow_pfn_pte(vma, address, ptep, flags); page = ERR_PTR(ret); goto out; @@ -457,7 +456,6 @@ retry: } if (flags & FOLL_SPLIT && PageTransCompound(page)) { - int ret; get_page(page); pte_unmap_unlock(ptep, ptl); lock_page(page); @@ -474,6 +472,19 @@ retry: page = ERR_PTR(-ENOMEM); goto out; } + /* + * We need to make the page accessible if and only if we are going + * to access its content (the FOLL_PIN case). Please see + * Documentation/core-api/pin_user_pages.rst for details. + */ + if (flags & FOLL_PIN) { + ret = arch_make_page_accessible(page); + if (ret) { + unpin_user_page(page); + page = ERR_PTR(ret); + goto out; + } + } if (flags & FOLL_TOUCH) { if ((flags & FOLL_WRITE) && !pte_dirty(pte) && !PageDirty(page)) @@ -2163,6 +2174,19 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, VM_BUG_ON_PAGE(compound_head(page) != head, page); + /* + * We need to make the page accessible if and only if we are + * going to access its content (the FOLL_PIN case). Please + * see Documentation/core-api/pin_user_pages.rst for + * details. + */ + if (flags & FOLL_PIN) { + ret = arch_make_page_accessible(page); + if (ret) { + unpin_user_page(page); + goto pte_unmap; + } + } SetPageReferenced(page); pages[*nr] = page; (*nr)++; |