fs/ceph/pagelist.c

   1
   2 #include <linux/gfp.h>
   3 #include <linux/pagemap.h>
   4 #include <linux/highmem.h>
   5
   6 #include "pagelist.h"
   7
   8 int ceph_pagelist_release(struct ceph_pagelist *pl)
   9 {
  10         if (pl->mapped_tail)
  11                 kunmap(pl->mapped_tail);
  12         while (!list_empty(&pl->head)) {
  13                 struct page *page = list_first_entry(&pl->head, struct page,
  14                                                      lru);
  15                 list_del(&page->lru);
  16                 __free_page(page);
  17         }
  18         return 0;
  19 }
  20
  21 static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
  22 {
  23         struct page *page = alloc_page(GFP_NOFS);
  24         if (!page)
  25                 return -ENOMEM;
  26         pl->room += PAGE_SIZE;
  27         list_add_tail(&page->lru, &pl->head);
  28         if (pl->mapped_tail)
  29                 kunmap(pl->mapped_tail);
  30         pl->mapped_tail = kmap(page);
  31         return 0;
  32 }
  33
  34 int ceph_pagelist_append(struct ceph_pagelist *pl, void *buf, size_t len)
  35 {
  36         while (pl->room < len) {
  37                 size_t bit = pl->room;
  38                 int ret;
  39
  40                 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
  41                        buf, bit);
  42                 pl->length += bit;
  43                 pl->room -= bit;
  44                 buf += bit;
  45                 len -= bit;
  46                 ret = ceph_pagelist_addpage(pl);
  47                 if (ret)
  48                         return ret;
  49         }
  50
  51         memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
  52         pl->length += len;
  53         pl->room -= len;
  54         return 0;
  55 }