#include #include #include #include #include #include static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl) { if (pl->mapped_tail) { struct page *page = list_entry(pl->head.prev, struct page, lru); kunmap(page); pl->mapped_tail = NULL; } } void ceph_pagelist_release(struct ceph_pagelist *pl) { if (!atomic_dec_and_test(&pl->refcnt)) return; 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); } ceph_pagelist_free_reserve(pl); kfree(pl); } EXPORT_SYMBOL(ceph_pagelist_release); static int ceph_pagelist_addpage(struct ceph_pagelist *pl) { struct page *page; if (!pl->num_pages_free) { page = __page_cache_alloc(GFP_NOFS); } else { page = list_first_entry(&pl->free_list, struct page, lru); list_del(&page->lru); --pl->num_pages_free; } if (!page) return -ENOMEM; pl->room += PAGE_SIZE; ceph_pagelist_unmap_tail(pl); list_add_tail(&page->lru, &pl->head); 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_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_MASK), buf, len); pl->length += len; pl->room -= len; return 0; } EXPORT_SYMBOL(ceph_pagelist_append); /* Allocate enough pages for a pagelist to append the given amount * of data without without allocating. * Returns: 0 on success, -ENOMEM on error. */ int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space) { if (space <= pl->room) return 0; space -= pl->room; space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */ while (space > pl->num_pages_free) { struct page *page = __page_cache_alloc(GFP_NOFS); if (!page) return -ENOMEM; list_add_tail(&page->lru, &pl->free_list); ++pl->num_pages_free; } return 0; } EXPORT_SYMBOL(ceph_pagelist_reserve); /* Free any pages that have been preallocated. */ int ceph_pagelist_free_reserve(struct ceph_pagelist *pl) { while (!list_empty(&pl->free_list)) { struct page *page = list_first_entry(&pl->free_list, struct page, lru); list_del(&page->lru); __free_page(page); --pl->num_pages_free; } BUG_ON(pl->num_pages_free); return 0; } EXPORT_SYMBOL(ceph_pagelist_free_reserve); /* Create a truncation point. */ void ceph_pagelist_set_cursor(struct ceph_pagelist *pl, struct ceph_pagelist_cursor *c) { c->pl = pl; c->page_lru = pl->head.prev; c->room = pl->room; } EXPORT_SYMBOL(ceph_pagelist_set_cursor); /* Truncate a pagelist to the given point. Move extra pages to reserve. * This won't sleep. * Returns: 0 on success, * -EINVAL if the pagelist doesn't match the trunc point pagelist */ int ceph_pagelist_truncate(struct ceph_pagelist *pl, struct ceph_pagelist_cursor *c) { struct page *page; if (pl != c->pl) return -EINVAL; ceph_pagelist_unmap_tail(pl); while (pl->head.prev != c->page_lru) { page = list_entry(pl->head.prev, struct page, lru); /* move from pagelist to reserve */ list_move_tail(&page->lru, &pl->free_list); ++pl->num_pages_free; } pl->room = c->room; if (!list_empty(&pl->head)) { page = list_entry(pl->head.prev, struct page, lru); pl->mapped_tail = kmap(page); } return 0; } EXPORT_SYMBOL(ceph_pagelist_truncate); 1b17d3d4ab0c8b47f81ccb1efcb75'/>


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