net/ceph/pagelist.c

   1
   2 #include <linux/module.h>
   3 #include <linux/gfp.h>
   4 #include <linux/pagemap.h>
   5 #include <linux/highmem.h>
   6 #include <linux/ceph/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 EXPORT_SYMBOL(ceph_pagelist_release);
  29
  30 static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
  31 {
  32         struct page *page = __page_cache_alloc(GFP_NOFS);
  33         if (!page)
  34                 return -ENOMEM;
  35         pl->room += PAGE_SIZE;
  36         list_add_tail(&page->lru, &pl->head);
  37         if (pl->mapped_tail)
  38                 ceph_pagelist_unmap_tail(pl);
  39         pl->mapped_tail = kmap(page);
  40         return 0;
  41 }
  42
  43 int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
  44 {
  45         while (pl->room < len) {
  46                 size_t bit = pl->room;
  47                 int ret;
  48
  49                 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
  50                        buf, bit);
  51                 pl->length += bit;
  52                 pl->room -= bit;
  53                 buf += bit;
  54                 len -= bit;
  55                 ret = ceph_pagelist_addpage(pl);
  56                 if (ret)
  57                         return ret;
  58         }
  59
  60         memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
  61         pl->length += len;
  62         pl->room -= len;
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(ceph_pagelist_append);