diff options
| -rw-r--r-- | mm/gup.c | 10 |
1 files changed, 8 insertions, 2 deletions
@@ -385,11 +385,17 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma, * @vma: vm_area_struct mapping @address * @address: virtual address to look up * @flags: flags modifying lookup behaviour - * @page_mask: on output, *page_mask is set according to the size of the page + * @ctx: contains dev_pagemap for %ZONE_DEVICE memory pinning and a + * pointer to output page_mask * * @flags can have FOLL_ flags set, defined in <linux/mm.h> * - * Returns the mapped (struct page *), %NULL if no mapping exists, or + * When getting pages from ZONE_DEVICE memory, the @ctx->pgmap caches + * the device's dev_pagemap metadata to avoid repeating expensive lookups. + * + * On output, the @ctx->page_mask is set according to the size of the page. + * + * Return: the mapped (struct page *), %NULL if no mapping exists, or * an error pointer if there is a mapping to something not represented * by a page descriptor (see also vm_normal_page()). */ |