64 строки
1.3 KiB
C
64 строки
1.3 KiB
C
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#include <linux/gfp.h>
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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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static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
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{
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struct page *page = list_entry(pl->head.prev, struct page,
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lru);
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kunmap(page);
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}
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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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ceph_pagelist_unmap_tail(pl);
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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 = __page_cache_alloc(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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ceph_pagelist_unmap_tail(pl);
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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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