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-rw-r--r--net/ceph/pagelist.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/net/ceph/pagelist.c b/net/ceph/pagelist.c
new file mode 100644
index 00000000000..3b146cfac18
--- /dev/null
+++ b/net/ceph/pagelist.c
@@ -0,0 +1,65 @@
+
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/ceph/pagelist.h>
+
+static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
+{
+ struct page *page = list_entry(pl->head.prev, struct page,
+ lru);
+ kunmap(page);
+}
+
+int ceph_pagelist_release(struct ceph_pagelist *pl)
+{
+ if (pl->mapped_tail)
+ ceph_pagelist_unmap_tail(pl);
+
+ while (!list_empty(&pl->head)) {
+ struct page *page = list_first_entry(&pl->head, struct page,
+ lru);
+ list_del(&page->lru);
+ __free_page(page);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(ceph_pagelist_release);
+
+static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
+{
+ struct page *page = __page_cache_alloc(GFP_NOFS);
+ if (!page)
+ return -ENOMEM;
+ pl->room += PAGE_SIZE;
+ list_add_tail(&page->lru, &pl->head);
+ if (pl->mapped_tail)
+ ceph_pagelist_unmap_tail(pl);
+ pl->mapped_tail = kmap(page);
+ return 0;
+}
+
+int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
+{
+ while (pl->room < len) {
+ size_t bit = pl->room;
+ int ret;
+
+ memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
+ buf, bit);
+ pl->length += bit;
+ pl->room -= bit;
+ buf += bit;
+ len -= bit;
+ ret = ceph_pagelist_addpage(pl);
+ if (ret)
+ return ret;
+ }
+
+ memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
+ pl->length += len;
+ pl->room -= len;
+ return 0;
+}
+EXPORT_SYMBOL(ceph_pagelist_append);