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 static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
   9 {
  10         struct page *page = list_entry(pl->head.prev, struct page,
  11                                        lru);
  12         kunmap(page);
  13 }
  14
  15 int ceph_pagelist_release(struct ceph_pagelist *pl)
  16 {
  17         if (pl->mapped_tail)
  18                 ceph_pagelist_unmap_tail(pl);
  19
  20         while (!list_empty(&pl->head)) {
  21                 struct page *page = list_first_entry(&pl->head, struct page,
  22                                                      lru);
  23                 list_del(&page->lru);
  24                 __free_page(page);
  25         }
  26         return 0;
  27 }
  28
  29 static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
  30 {
  31         struct page *page = __page_cache_alloc(GFP_NOFS);
  32         if (!page)
  33                 return -ENOMEM;
  34         pl->room += PAGE_SIZE;
  35         list_add_tail(&page->lru, &pl->head);
  36         if (pl->mapped_tail)
  37                 ceph_pagelist_unmap_tail(pl);
  38         pl->mapped_tail = kmap(page);
  39         return 0;
  40 }
  41
  42 int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
  43 {
  44         while (pl->room < len) {
  45                 size_t bit = pl->room;
  46                 int ret;
  47
  48                 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
  49                        buf, bit);
  50                 pl->length += bit;
  51                 pl->room -= bit;
  52                 buf += bit;
  53                 len -= bit;
  54                 ret = ceph_pagelist_addpage(pl);
  55                 if (ret)
  56                         return ret;
  57         }
  58
  59         memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
  60         pl->length += len;
  61         pl->room -= len;
  62         return 0;
  63 }