58bb3b374b
The ceph_pagelist is a simple list of whole pages, strung together via their lru list_head. It facilitates encoding to a "buffer" of unknown size. Allow its use in place of the ceph_msg page vector. This will be used to fix the huge buffer preallocation woes of MDS reconnection. Signed-off-by: Sage Weil <sage@newdream.net>
55 lines
1.1 KiB
C
55 lines
1.1 KiB
C
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include "pagelist.h"
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int ceph_pagelist_release(struct ceph_pagelist *pl)
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{
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if (pl->mapped_tail)
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kunmap(pl->mapped_tail);
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while (!list_empty(&pl->head)) {
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struct page *page = list_first_entry(&pl->head, struct page,
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lru);
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list_del(&page->lru);
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__free_page(page);
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}
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return 0;
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}
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static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
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{
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struct page *page = alloc_page(GFP_NOFS);
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if (!page)
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return -ENOMEM;
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pl->room += PAGE_SIZE;
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list_add_tail(&page->lru, &pl->head);
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if (pl->mapped_tail)
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kunmap(pl->mapped_tail);
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pl->mapped_tail = kmap(page);
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return 0;
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}
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int ceph_pagelist_append(struct ceph_pagelist *pl, void *buf, size_t len)
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{
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while (pl->room < len) {
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size_t bit = pl->room;
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int ret;
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memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
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buf, bit);
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pl->length += bit;
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pl->room -= bit;
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buf += bit;
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len -= bit;
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ret = ceph_pagelist_addpage(pl);
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if (ret)
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return ret;
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}
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memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
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pl->length += len;
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pl->room -= len;
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return 0;
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}
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