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171 lines
4.0 KiB
171 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/module.h> |
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#include <linux/gfp.h> |
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#include <linux/slab.h> |
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#include <linux/pagemap.h> |
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#include <linux/highmem.h> |
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#include <linux/ceph/pagelist.h> |
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struct ceph_pagelist *ceph_pagelist_alloc(gfp_t gfp_flags) |
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{ |
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struct ceph_pagelist *pl; |
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pl = kmalloc(sizeof(*pl), gfp_flags); |
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if (!pl) |
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return NULL; |
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INIT_LIST_HEAD(&pl->head); |
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pl->mapped_tail = NULL; |
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pl->length = 0; |
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pl->room = 0; |
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INIT_LIST_HEAD(&pl->free_list); |
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pl->num_pages_free = 0; |
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refcount_set(&pl->refcnt, 1); |
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return pl; |
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} |
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EXPORT_SYMBOL(ceph_pagelist_alloc); |
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static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl) |
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{ |
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if (pl->mapped_tail) { |
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struct page *page = list_entry(pl->head.prev, struct page, lru); |
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kunmap(page); |
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pl->mapped_tail = NULL; |
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} |
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} |
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void ceph_pagelist_release(struct ceph_pagelist *pl) |
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{ |
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if (!refcount_dec_and_test(&pl->refcnt)) |
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return; |
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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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ceph_pagelist_free_reserve(pl); |
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kfree(pl); |
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} |
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EXPORT_SYMBOL(ceph_pagelist_release); |
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static int ceph_pagelist_addpage(struct ceph_pagelist *pl) |
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{ |
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struct page *page; |
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if (!pl->num_pages_free) { |
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page = __page_cache_alloc(GFP_NOFS); |
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} else { |
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page = list_first_entry(&pl->free_list, struct page, lru); |
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list_del(&page->lru); |
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--pl->num_pages_free; |
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} |
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if (!page) |
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return -ENOMEM; |
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pl->room += PAGE_SIZE; |
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ceph_pagelist_unmap_tail(pl); |
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list_add_tail(&page->lru, &pl->head); |
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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, const 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_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_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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EXPORT_SYMBOL(ceph_pagelist_append); |
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/* Allocate enough pages for a pagelist to append the given amount |
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* of data without allocating. |
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* Returns: 0 on success, -ENOMEM on error. |
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*/ |
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int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space) |
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{ |
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if (space <= pl->room) |
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return 0; |
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space -= pl->room; |
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space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */ |
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while (space > pl->num_pages_free) { |
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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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list_add_tail(&page->lru, &pl->free_list); |
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++pl->num_pages_free; |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL(ceph_pagelist_reserve); |
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/* Free any pages that have been preallocated. */ |
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int ceph_pagelist_free_reserve(struct ceph_pagelist *pl) |
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{ |
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while (!list_empty(&pl->free_list)) { |
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struct page *page = list_first_entry(&pl->free_list, |
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struct page, lru); |
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list_del(&page->lru); |
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__free_page(page); |
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--pl->num_pages_free; |
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} |
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BUG_ON(pl->num_pages_free); |
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return 0; |
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} |
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EXPORT_SYMBOL(ceph_pagelist_free_reserve); |
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/* Create a truncation point. */ |
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void ceph_pagelist_set_cursor(struct ceph_pagelist *pl, |
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struct ceph_pagelist_cursor *c) |
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{ |
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c->pl = pl; |
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c->page_lru = pl->head.prev; |
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c->room = pl->room; |
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} |
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EXPORT_SYMBOL(ceph_pagelist_set_cursor); |
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/* Truncate a pagelist to the given point. Move extra pages to reserve. |
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* This won't sleep. |
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* Returns: 0 on success, |
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* -EINVAL if the pagelist doesn't match the trunc point pagelist |
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*/ |
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int ceph_pagelist_truncate(struct ceph_pagelist *pl, |
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struct ceph_pagelist_cursor *c) |
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{ |
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struct page *page; |
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if (pl != c->pl) |
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return -EINVAL; |
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ceph_pagelist_unmap_tail(pl); |
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while (pl->head.prev != c->page_lru) { |
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page = list_entry(pl->head.prev, struct page, lru); |
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/* move from pagelist to reserve */ |
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list_move_tail(&page->lru, &pl->free_list); |
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++pl->num_pages_free; |
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} |
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pl->room = c->room; |
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if (!list_empty(&pl->head)) { |
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page = list_entry(pl->head.prev, struct page, lru); |
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pl->mapped_tail = kmap(page); |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL(ceph_pagelist_truncate);
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