fs/ceph/pagelist.c

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