diff options
Diffstat (limited to 'drivers/staging/rtl8192su/ieee80211/scatterwalk.c')
-rw-r--r-- | drivers/staging/rtl8192su/ieee80211/scatterwalk.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/staging/rtl8192su/ieee80211/scatterwalk.c b/drivers/staging/rtl8192su/ieee80211/scatterwalk.c new file mode 100644 index 000000000000..49f401fbce88 --- /dev/null +++ b/drivers/staging/rtl8192su/ieee80211/scatterwalk.c @@ -0,0 +1,126 @@ +/* + * Cryptographic API. + * + * Cipher operations. + * + * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> + * 2002 Adam J. Richter <adam@yggdrasil.com> + * 2004 Jean-Luc Cooke <jlcooke@certainkey.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + */ +#include "kmap_types.h" + +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <asm/scatterlist.h> +#include "internal.h" +#include "scatterwalk.h" + +enum km_type crypto_km_types[] = { + KM_USER0, + KM_USER1, + KM_SOFTIRQ0, + KM_SOFTIRQ1, +}; + +void *scatterwalk_whichbuf(struct scatter_walk *walk, unsigned int nbytes, void *scratch) +{ + if (nbytes <= walk->len_this_page && + (((unsigned long)walk->data) & (PAGE_CACHE_SIZE - 1)) + nbytes <= + PAGE_CACHE_SIZE) + return walk->data; + else + return scratch; +} + +static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) +{ + if (out) + memcpy(sgdata, buf, nbytes); + else + memcpy(buf, sgdata, nbytes); +} + +void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) +{ + unsigned int rest_of_page; + + walk->sg = sg; + + walk->page = sg->page; + walk->len_this_segment = sg->length; + + rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1)); + walk->len_this_page = min(sg->length, rest_of_page); + walk->offset = sg->offset; +} + +void scatterwalk_map(struct scatter_walk *walk, int out) +{ + walk->data = crypto_kmap(walk->page, out) + walk->offset; +} + +static void scatterwalk_pagedone(struct scatter_walk *walk, int out, + unsigned int more) +{ + /* walk->data may be pointing the first byte of the next page; + however, we know we transfered at least one byte. So, + walk->data - 1 will be a virtual address in the mapped page. */ + + if (out) + flush_dcache_page(walk->page); + + if (more) { + walk->len_this_segment -= walk->len_this_page; + + if (walk->len_this_segment) { + walk->page++; + walk->len_this_page = min(walk->len_this_segment, + (unsigned)PAGE_CACHE_SIZE); + walk->offset = 0; + } + else + scatterwalk_start(walk, sg_next(walk->sg)); + } +} + +void scatterwalk_done(struct scatter_walk *walk, int out, int more) +{ + crypto_kunmap(walk->data, out); + if (walk->len_this_page == 0 || !more) + scatterwalk_pagedone(walk, out, more); +} + +/* + * Do not call this unless the total length of all of the fragments + * has been verified as multiple of the block size. + */ +int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, + size_t nbytes, int out) +{ + if (buf != walk->data) { + while (nbytes > walk->len_this_page) { + memcpy_dir(buf, walk->data, walk->len_this_page, out); + buf += walk->len_this_page; + nbytes -= walk->len_this_page; + + crypto_kunmap(walk->data, out); + scatterwalk_pagedone(walk, out, 1); + scatterwalk_map(walk, out); + } + + memcpy_dir(buf, walk->data, nbytes, out); + } + + walk->offset += nbytes; + walk->len_this_page -= nbytes; + walk->len_this_segment -= nbytes; + return 0; +} |