root/include/crypto/scatterwalk.h

INCLUDED FROM

DEFINITIONS

1. crypto_kmap_type
2. crypto_kmap
3. crypto_kunmap
4. crypto_yield
5. scatterwalk_sg_chain
6. scatterwalk_sg_next
7. scatterwalk_samebuf
8. scatterwalk_pagelen
9. scatterwalk_clamp
10. scatterwalk_advance
11. scatterwalk_aligned
12. scatterwalk_page
13. scatterwalk_unmap

/*
 * Cryptographic scatter and gather helpers.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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.
 *
 */

#ifndef _CRYPTO_SCATTERWALK_H
#define _CRYPTO_SCATTERWALK_H

#include <asm/kmap_types.h>
#include <crypto/algapi.h>
#include <linux/hardirq.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>

static inline enum km_type crypto_kmap_type(int out)
{
        enum km_type type;

        if (in_softirq())
                type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
        else
                type = out * (KM_USER1 - KM_USER0) + KM_USER0;

        return type;
}

static inline void *crypto_kmap(struct page *page, int out)
{
        return kmap_atomic(page, crypto_kmap_type(out));
}

static inline void crypto_kunmap(void *vaddr, int out)
{
        kunmap_atomic(vaddr, crypto_kmap_type(out));
}

static inline void crypto_yield(u32 flags)
{
        if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
                cond_resched();
}

static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
                                        struct scatterlist *sg2)
{
        sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
        sg1[num - 1].page_link &= ~0x02;
}

static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
{
        if (sg_is_last(sg))
                return NULL;

        return (++sg)->length ? sg : (void *)sg_page(sg);
}

static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
                                                struct scatter_walk *walk_out)
{
        return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
                 (int)(walk_in->offset - walk_out->offset));
}

static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
{
        unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
        unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
        return len_this_page > len ? len : len_this_page;
}

static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
                                             unsigned int nbytes)
{
        unsigned int len_this_page = scatterwalk_pagelen(walk);
        return nbytes > len_this_page ? len_this_page : nbytes;
}

static inline void scatterwalk_advance(struct scatter_walk *walk,
                                       unsigned int nbytes)
{
        walk->offset += nbytes;
}

static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
                                               unsigned int alignmask)
{
        return !(walk->offset & alignmask);
}

static inline struct page *scatterwalk_page(struct scatter_walk *walk)
{
        return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
}

static inline void scatterwalk_unmap(void *vaddr, int out)
{
        crypto_kunmap(vaddr, out);
}

void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
                            size_t nbytes, int out);
void *scatterwalk_map(struct scatter_walk *walk, int out);
void scatterwalk_done(struct scatter_walk *walk, int out, int more);

void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
                              unsigned int start, unsigned int nbytes, int out);

#endif  /* _CRYPTO_SCATTERWALK_H */