Blame view
fs/squashfs/page_actor.c
3.35 KB
81f7e3824
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 |
/* * Copyright (c) 2013 * Phillip Lougher <phillip@squashfs.org.uk> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. */ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/pagemap.h> #include <linux/buffer_head.h> #include "page_actor.h" struct squashfs_page_actor *squashfs_page_actor_init(struct page **page, int pages, int length, void (*release_pages)(struct page **, int, int)) { struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL); if (actor == NULL) return NULL; actor->length = length ? : pages * PAGE_SIZE; actor->page = page; actor->pages = pages; actor->next_page = 0; actor->pageaddr = NULL; actor->release_pages = release_pages; return actor; } void squashfs_page_actor_free(struct squashfs_page_actor *actor, int error) { if (!actor) return; if (actor->release_pages) actor->release_pages(actor->page, actor->pages, error); kfree(actor); } void squashfs_actor_to_buf(struct squashfs_page_actor *actor, void *buf, int length) { void *pageaddr; int pos = 0, avail, i; for (i = 0; i < actor->pages && pos < length; ++i) { avail = min_t(int, length - pos, PAGE_SIZE); if (actor->page[i]) { pageaddr = kmap_atomic(actor->page[i]); memcpy(buf + pos, pageaddr, avail); kunmap_atomic(pageaddr); } pos += avail; } } void squashfs_buf_to_actor(void *buf, struct squashfs_page_actor *actor, int length) { void *pageaddr; int pos = 0, avail, i; for (i = 0; i < actor->pages && pos < length; ++i) { avail = min_t(int, length - pos, PAGE_SIZE); if (actor->page[i]) { pageaddr = kmap_atomic(actor->page[i]); memcpy(pageaddr, buf + pos, avail); kunmap_atomic(pageaddr); } pos += avail; } } void squashfs_bh_to_actor(struct buffer_head **bh, int nr_buffers, struct squashfs_page_actor *actor, int offset, int length, int blksz) { void *kaddr = NULL; int bytes = 0, pgoff = 0, b = 0, p = 0, avail, i; while (bytes < length) { if (actor->page[p]) { kaddr = kmap_atomic(actor->page[p]); while (pgoff < PAGE_SIZE && bytes < length) { avail = min_t(int, blksz - offset, PAGE_SIZE - pgoff); memcpy(kaddr + pgoff, bh[b]->b_data + offset, avail); pgoff += avail; bytes += avail; offset = (offset + avail) % blksz; if (!offset) { put_bh(bh[b]); ++b; } } kunmap_atomic(kaddr); pgoff = 0; } else { for (i = 0; i < PAGE_SIZE / blksz; ++i) { if (bh[b]) put_bh(bh[b]); ++b; } bytes += PAGE_SIZE; } ++p; } } void squashfs_bh_to_buf(struct buffer_head **bh, int nr_buffers, void *buf, int offset, int length, int blksz) { int i, avail, bytes = 0; for (i = 0; i < nr_buffers && bytes < length; ++i) { avail = min_t(int, length - bytes, blksz - offset); if (bh[i]) { memcpy(buf + bytes, bh[i]->b_data + offset, avail); put_bh(bh[i]); } bytes += avail; offset = 0; } } void free_page_array(struct page **page, int nr_pages) { int i; for (i = 0; i < nr_pages; ++i) __free_page(page[i]); kfree(page); } struct page **alloc_page_array(int nr_pages, int gfp_mask) { int i; struct page **page; page = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); if (!page) return NULL; for (i = 0; i < nr_pages; ++i) { page[i] = alloc_page(gfp_mask); if (!page[i]) { free_page_array(page, i); return NULL; } } return page; } |