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    SubjectRe: dm-crypt using kthread
    On Sun, Feb 15, 2004 at 09:58:39PM -0500, Jeff Garzik wrote:

    > This sounds like a lot of work, just to reimplement what a semaphore
    > does for you :)

    I've fixed the small bugs you guys found and tried some more alternatives.
    I've got three versions now:

    - kthread and set_current_state/schedule/wake_up_process
    - kthread and semaphores
    - workqueue

    The version using a workqueue is the shortest of all:

    diff -Nur linux-2.6.3-rc3-mm1.orig/drivers/md/dm-crypt.c linux-2.6.3-rc3-mm1/drivers/md/dm-crypt.c
    --- linux-2.6.3-rc3-mm1.orig/drivers/md/dm-crypt.c 1970-01-01 01:00:00.000000000 +0100
    +++ linux-2.6.3-rc3-mm1/drivers/md/dm-crypt.c 2004-02-16 01:47:37.000000000 +0100
    @@ -0,0 +1,776 @@
    +/*
    + * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
    + *
    + * This file is released under the GPL.
    + */
    +
    +#include <linux/module.h>
    +#include <linux/init.h>
    +#include <linux/kernel.h>
    +#include <linux/bio.h>
    +#include <linux/mempool.h>
    +#include <linux/slab.h>
    +#include <linux/crypto.h>
    +#include <linux/spinlock.h>
    +#include <linux/workqueue.h>
    +#include <asm/scatterlist.h>
    +
    +#include "dm.h"
    +
    +/*
    + * per bio private data
    + */
    +struct crypt_io {
    + struct dm_target *target;
    + struct bio *bio;
    + struct bio *first_clone;
    + struct work_struct work;
    + atomic_t pending;
    + int error;
    +};
    +
    +/*
    + * context holding the current state of a multi-part conversion
    + */
    +struct convert_context {
    + struct bio *bio_in;
    + struct bio *bio_out;
    + unsigned int offset_in;
    + unsigned int offset_out;
    + int idx_in;
    + int idx_out;
    + sector_t sector;
    + int write;
    +};
    +
    +/*
    + * Crypt: maps a linear range of a block device
    + * and encrypts / decrypts at the same time.
    + */
    +struct crypt_config {
    + struct dm_dev *dev;
    + sector_t start;
    +
    + /*
    + * pool for per bio private data and
    + * for encryption buffer pages
    + */
    + mempool_t *io_pool;
    + mempool_t *page_pool;
    +
    + /*
    + * crypto related data
    + */
    + struct crypto_tfm *tfm;
    + sector_t iv_offset;
    + int (*iv_generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
    + int iv_size;
    + int key_size;
    + u8 key[0];
    +};
    +
    +#define MIN_IOS 256
    +#define MIN_POOL_PAGES 32
    +#define MIN_BIO_PAGES 8
    +
    +static kmem_cache_t *_crypt_io_pool;
    +
    +/*
    + * Mempool alloc and free functions for the page
    + */
    +static void *mempool_alloc_page(int gfp_mask, void *data)
    +{
    + return alloc_page(gfp_mask);
    +}
    +
    +static void mempool_free_page(void *page, void *data)
    +{
    + __free_page(page);
    +}
    +
    +
    +/*
    + * Different IV generation algorithms
    + */
    +static int crypt_iv_plain(struct crypt_config *cc, u8 *iv, sector_t sector)
    +{
    + *(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
    + if (cc->iv_size > sizeof(u32) / sizeof(u8))
    + memset(iv + (sizeof(u32) / sizeof(u8)), 0,
    + cc->iv_size - (sizeof(u32) / sizeof(u8)));
    +
    + return 0;
    +}
    +
    +static inline int
    +crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
    + struct scatterlist *in, unsigned int length,
    + int write, sector_t sector)
    +{
    + u8 iv[cc->iv_size];
    + int r;
    +
    + if (cc->iv_generator) {
    + r = cc->iv_generator(cc, iv, sector);
    + if (r < 0)
    + return r;
    +
    + if (write)
    + r = crypto_cipher_encrypt_iv(cc->tfm, out, in, length, iv);
    + else
    + r = crypto_cipher_decrypt_iv(cc->tfm, out, in, length, iv);
    + } else {
    + if (write)
    + r = crypto_cipher_encrypt(cc->tfm, out, in, length);
    + else
    + r = crypto_cipher_decrypt(cc->tfm, out, in, length);
    + }
    +
    + return r;
    +}
    +
    +static void
    +crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx,
    + struct bio *bio_out, struct bio *bio_in,
    + sector_t sector, int write)
    +{
    + ctx->bio_in = bio_in;
    + ctx->bio_out = bio_out;
    + ctx->offset_in = 0;
    + ctx->offset_out = 0;
    + ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
    + ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
    + ctx->sector = sector + cc->iv_offset;
    + ctx->write = write;
    +}
    +
    +/*
    + * Encrypt / decrypt data from one bio to another one (can be the same one)
    + */
    +static int crypt_convert(struct crypt_config *cc,
    + struct convert_context *ctx)
    +{
    + int r = 0;
    +
    + while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
    + ctx->idx_out < ctx->bio_out->bi_vcnt) {
    + struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
    + struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
    + struct scatterlist sg_in = {
    + .page = bv_in->bv_page,
    + .offset = bv_in->bv_offset + ctx->offset_in,
    + .length = 1 << SECTOR_SHIFT
    + };
    + struct scatterlist sg_out = {
    + .page = bv_out->bv_page,
    + .offset = bv_out->bv_offset + ctx->offset_out,
    + .length = 1 << SECTOR_SHIFT
    + };
    +
    + ctx->offset_in += sg_in.length;
    + if (ctx->offset_in >= bv_in->bv_len) {
    + ctx->offset_in = 0;
    + ctx->idx_in++;
    + }
    +
    + ctx->offset_out += sg_out.length;
    + if (ctx->offset_out >= bv_out->bv_len) {
    + ctx->offset_out = 0;
    + ctx->idx_out++;
    + }
    +
    + r = crypt_convert_scatterlist(cc, &sg_out, &sg_in, sg_in.length,
    + ctx->write, ctx->sector);
    + if (r < 0)
    + break;
    +
    + ctx->sector++;
    + }
    +
    + return r;
    +}
    +
    +/*
    + * Generate a new unfragmented bio with the given size
    + * This should never violate the device limitations
    + * May return a smaller bio when running out of pages
    + */
    +static struct bio *
    +crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
    + struct bio *base_bio, int *bio_vec_idx)
    +{
    + struct bio *bio;
    + int nr_iovecs = dm_div_up(size, PAGE_SIZE);
    + int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
    + int flags = current->flags;
    + int i;
    +
    + /*
    + * Tell VM to act less aggressively and fail earlier.
    + * This is not necessary but increases throughput.
    + * FIXME: Is this really intelligent?
    + */
    + current->flags &= ~PF_MEMALLOC;
    +
    + if (base_bio)
    + bio = bio_clone(base_bio, GFP_NOIO);
    + else
    + bio = bio_alloc(GFP_NOIO, nr_iovecs);
    + if (!bio) {
    + if (flags & PF_MEMALLOC)
    + current->flags |= PF_MEMALLOC;
    + return NULL;
    + }
    +
    + /* if the last bio was not complete, continue where that one ended */
    + bio->bi_idx = *bio_vec_idx;
    + bio->bi_vcnt = *bio_vec_idx;
    + bio->bi_size = 0;
    + bio->bi_flags &= ~(1 << BIO_SEG_VALID);
    +
    + /* bio->bi_idx pages have already been allocated */
    + size -= bio->bi_idx * PAGE_SIZE;
    +
    + for(i = bio->bi_idx; i < nr_iovecs; i++) {
    + struct bio_vec *bv = bio_iovec_idx(bio, i);
    +
    + bv->bv_page = mempool_alloc(cc->page_pool, gfp_mask);
    + if (!bv->bv_page)
    + break;
    +
    + /*
    + * if additional pages cannot be allocated without waiting,
    + * return a partially allocated bio, the caller will then try
    + * to allocate additional bios while submitting this partial bio
    + */
    + if ((i - bio->bi_idx) == (MIN_BIO_PAGES - 1))
    + gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
    +
    + bv->bv_offset = 0;
    + if (size > PAGE_SIZE)
    + bv->bv_len = PAGE_SIZE;
    + else
    + bv->bv_len = size;
    +
    + bio->bi_size += bv->bv_len;
    + bio->bi_vcnt++;
    + size -= bv->bv_len;
    + }
    +
    + if (flags & PF_MEMALLOC)
    + current->flags |= PF_MEMALLOC;
    +
    + if (!bio->bi_size) {
    + bio_put(bio);
    + return NULL;
    + }
    +
    + /*
    + * Remember the last bio_vec allocated to be able
    + * to correctly continue after the splitting.
    + */
    + *bio_vec_idx = bio->bi_vcnt;
    +
    + return bio;
    +}
    +
    +static void crypt_free_buffer_pages(struct crypt_config *cc,
    + struct bio *bio, unsigned int bytes)
    +{
    + unsigned int start, end;
    + struct bio_vec *bv;
    + int i;
    +
    + /*
    + * This is ugly, but Jens Axboe thinks that using bi_idx in the
    + * endio function is too dangerous at the moment, so I calculate the
    + * correct position using bi_vcnt and bi_size.
    + * The bv_offset and bv_len fields might already be modified but we
    + * know that we always allocated whole pages.
    + * A fix to the bi_idx issue in the kernel is in the works, so
    + * we will hopefully be able to revert to the cleaner solution soon.
    + */
    + i = bio->bi_vcnt - 1;
    + bv = bio_iovec_idx(bio, i);
    + end = (i << PAGE_SHIFT) + (bv->bv_offset + bv->bv_len) - bio->bi_size;
    + start = end - bytes;
    +
    + start >>= PAGE_SHIFT;
    + if (!bio->bi_size)
    + end = bio->bi_vcnt;
    + else
    + end >>= PAGE_SHIFT;
    +
    + for(i = start; i < end; i++) {
    + bv = bio_iovec_idx(bio, i);
    + BUG_ON(!bv->bv_page);
    + mempool_free(bv->bv_page, cc->page_pool);
    + bv->bv_page = NULL;
    + }
    +}
    +
    +/*
    + * One of the bios was finished. Check for completion of
    + * the whole request and correctly clean up the buffer.
    + */
    +static void dec_pending(struct crypt_io *io, int error)
    +{
    + struct crypt_config *cc = (struct crypt_config *) io->target->private;
    +
    + if (error < 0)
    + io->error = error;
    +
    + if (!atomic_dec_and_test(&io->pending))
    + return;
    +
    + if (io->first_clone)
    + bio_put(io->first_clone);
    +
    + bio_endio(io->bio, io->bio->bi_size, io->error);
    +
    + mempool_free(io, cc->io_pool);
    +}
    +
    +/*
    + * kcryptd:
    + *
    + * Needed because it would be very unwise to do decryption in an
    + * interrupt context, so bios returning from read requests get
    + * queued here.
    + */
    +static struct workqueue_struct *_kcryptd_workqueue;
    +
    +static void kcryptd_do_work(void *data)
    +{
    + struct crypt_io *io = (struct crypt_io *) data;
    + struct crypt_config *cc = (struct crypt_config *) io->target->private;
    + struct convert_context ctx;
    + int r;
    +
    + crypt_convert_init(cc, &ctx, io->bio, io->bio,
    + io->bio->bi_sector - io->target->begin, 0);
    + r = crypt_convert(cc, &ctx);
    +
    + dec_pending(io, r);
    +}
    +
    +static void kcryptd_queue_io(struct crypt_io *io)
    +{
    + /* with the work struct in crypt_io we can only queue whole io's */
    + BUG_ON(atomic_read(&io->pending) != 1);
    +
    + INIT_WORK(&io->work, kcryptd_do_work, io);
    + queue_work(_kcryptd_workqueue, &io->work);
    +}
    +
    +/*
    + * Decode key from its hex representation
    + */
    +static int crypt_decode_key(u8 *key, char *hex, int size)
    +{
    + char buffer[3];
    + char *endp;
    + int i;
    +
    + buffer[2] = '\0';
    +
    + for(i = 0; i < size; i++) {
    + buffer[0] = *hex++;
    + buffer[1] = *hex++;
    +
    + key[i] = (u8)simple_strtoul(buffer, &endp, 16);
    +
    + if (endp != &buffer[2])
    + return -EINVAL;
    + }
    +
    + if (*hex != '\0')
    + return -EINVAL;
    +
    + return 0;
    +}
    +
    +/*
    + * Encode key into its hex representation
    + */
    +static void crypt_encode_key(char *hex, u8 *key, int size)
    +{
    + int i;
    +
    + for(i = 0; i < size; i++) {
    + sprintf(hex, "%02x", *key);
    + hex += 2;
    + key++;
    + }
    +}
    +
    +/*
    + * Construct an encryption mapping:
    + * <cipher> <key> <iv_offset> <dev_path> <start>
    + */
    +static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
    +{
    + struct crypt_config *cc;
    + struct crypto_tfm *tfm;
    + char *tmp;
    + char *cipher;
    + char *mode;
    + int crypto_flags;
    + int key_size;
    +
    + if (argc != 5) {
    + ti->error = "dm-crypt: Not enough arguments";
    + return -EINVAL;
    + }
    +
    + tmp = argv[0];
    + cipher = strsep(&tmp, "-");
    + mode = strsep(&tmp, "-");
    +
    + if (tmp)
    + DMWARN("dm-crypt: Unexpected additional cipher options");
    +
    + key_size = strlen(argv[1]) >> 1;
    +
    + cc = kmalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
    + if (cc == NULL) {
    + ti->error =
    + "dm-crypt: Cannot allocate transparent encryption context";
    + return -ENOMEM;
    + }
    +
    + if (!mode || strcmp(mode, "plain") == 0)
    + cc->iv_generator = crypt_iv_plain;
    + else if (strcmp(mode, "ecb") == 0)
    + cc->iv_generator = NULL;
    + else {
    + ti->error = "dm-crypt: Invalid chaining mode";
    + goto bad1;
    + }
    +
    + if (cc->iv_generator)
    + crypto_flags = CRYPTO_TFM_MODE_CBC;
    + else
    + crypto_flags = CRYPTO_TFM_MODE_ECB;
    +
    + tfm = crypto_alloc_tfm(cipher, crypto_flags);
    + if (!tfm) {
    + ti->error = "dm-crypt: Error allocating crypto tfm";
    + goto bad1;
    + }
    +
    + if (tfm->crt_u.cipher.cit_decrypt_iv && tfm->crt_u.cipher.cit_encrypt_iv)
    + /* at least a 32 bit sector number should fit in our buffer */
    + cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
    + (unsigned int)(sizeof(u32) / sizeof(u8)));
    + else {
    + cc->iv_size = 0;
    + if (cc->iv_generator) {
    + DMWARN("dm-crypt: Selected cipher does not support IVs");
    + cc->iv_generator = NULL;
    + }
    + }
    +
    + cc->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
    + mempool_free_slab, _crypt_io_pool);
    + if (!cc->io_pool) {
    + ti->error = "dm-crypt: Cannot allocate crypt io mempool";
    + goto bad2;
    + }
    +
    + cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page,
    + mempool_free_page, NULL);
    + if (!cc->page_pool) {
    + ti->error = "dm-crypt: Cannot allocate page mempool";
    + goto bad3;
    + }
    +
    + cc->tfm = tfm;
    + cc->key_size = key_size;
    + if ((key_size == 0 && strcmp(argv[1], "-") != 0)
    + || crypt_decode_key(cc->key, argv[1], key_size) < 0) {
    + ti->error = "dm-crypt: Error decoding key";
    + goto bad4;
    + }
    +
    + if (tfm->crt_u.cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
    + ti->error = "dm-crypt: Error setting key";
    + goto bad4;
    + }
    +
    + if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) {
    + ti->error = "dm-crypt: Invalid iv_offset sector";
    + goto bad4;
    + }
    +
    + if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) {
    + ti->error = "dm-crypt: Invalid device sector";
    + goto bad4;
    + }
    +
    + if (dm_get_device(ti, argv[3], cc->start, ti->len,
    + dm_table_get_mode(ti->table), &cc->dev)) {
    + ti->error = "dm-crypt: Device lookup failed";
    + goto bad4;
    + }
    +
    + ti->private = cc;
    + return 0;
    +
    +bad4:
    + mempool_destroy(cc->page_pool);
    +bad3:
    + mempool_destroy(cc->io_pool);
    +bad2:
    + crypto_free_tfm(tfm);
    +bad1:
    + kfree(cc);
    + return -EINVAL;
    +}
    +
    +static void crypt_dtr(struct dm_target *ti)
    +{
    + struct crypt_config *cc = (struct crypt_config *) ti->private;
    +
    + mempool_destroy(cc->page_pool);
    + mempool_destroy(cc->io_pool);
    +
    + crypto_free_tfm(cc->tfm);
    + dm_put_device(ti, cc->dev);
    + kfree(cc);
    +}
    +
    +static int crypt_endio(struct bio *bio, unsigned int done, int error)
    +{
    + struct crypt_io *io = (struct crypt_io *) bio->bi_private;
    + struct crypt_config *cc = (struct crypt_config *) io->target->private;
    +
    + if (bio_rw(bio) == WRITE) {
    + /*
    + * free the processed pages, even if
    + * it's only a partially completed write
    + */
    + crypt_free_buffer_pages(cc, bio, done);
    + }
    +
    + if (bio->bi_size)
    + return 1;
    +
    + bio_put(bio);
    +
    + /*
    + * successful reads are decrypted by the worker thread
    + */
    + if ((bio_rw(bio) == READ || bio_rw(bio) == READA)
    + && bio_flagged(bio, BIO_UPTODATE)) {
    + kcryptd_queue_io(io);
    + return 0;
    + }
    +
    + dec_pending(io, error);
    + return error;
    +}
    +
    +static inline struct bio *
    +crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
    + sector_t sector, int *bvec_idx, struct convert_context *ctx)
    +{
    + struct bio *clone;
    +
    + if (bio_rw(bio) == WRITE) {
    + clone = crypt_alloc_buffer(cc, bio->bi_size,
    + io->first_clone, bvec_idx);
    + if (clone) {
    + ctx->bio_out = clone;
    + if (crypt_convert(cc, ctx) < 0) {
    + crypt_free_buffer_pages(cc, clone,
    + clone->bi_size);
    + bio_put(clone);
    + return NULL;
    + }
    + }
    + } else
    + clone = bio_clone(bio, GFP_NOIO);
    +
    + if (!clone)
    + return NULL;
    +
    + clone->bi_private = io;
    + clone->bi_end_io = crypt_endio;
    + clone->bi_bdev = cc->dev->bdev;
    + clone->bi_sector = cc->start + sector;
    + clone->bi_rw = bio->bi_rw;
    +
    + return clone;
    +}
    +
    +static int crypt_map(struct dm_target *ti, struct bio *bio)
    +{
    + struct crypt_config *cc = (struct crypt_config *) ti->private;
    + struct crypt_io *io = mempool_alloc(cc->io_pool, GFP_NOIO);
    + struct convert_context ctx;
    + struct bio *clone;
    + unsigned int remaining = bio->bi_size;
    + sector_t sector = bio->bi_sector - ti->begin;
    + int bvec_idx = 0;
    +
    + io->target = ti;
    + io->bio = bio;
    + io->first_clone = NULL;
    + io->error = 0;
    + atomic_set(&io->pending, 1); /* hold a reference */
    +
    + if (bio_rw(bio) == WRITE)
    + crypt_convert_init(cc, &ctx, NULL, bio, sector, 1);
    +
    + /*
    + * The allocated buffers can be smaller than the whole bio,
    + * so repeat the whole process until all the data can be handled.
    + */
    + while (remaining) {
    + clone = crypt_clone(cc, io, bio, sector, &bvec_idx, &ctx);
    + if (!clone)
    + goto cleanup;
    +
    + if (!io->first_clone) {
    + /*
    + * hold a reference to the first clone, because it
    + * holds the bio_vec array and that can't be freed
    + * before all other clones are released
    + */
    + bio_get(clone);
    + io->first_clone = clone;
    + }
    + atomic_inc(&io->pending);
    +
    + remaining -= clone->bi_size;
    + sector += bio_sectors(clone);
    +
    + generic_make_request(clone);
    + }
    +
    + /* drop reference, clones could have returned before we reach this */
    + dec_pending(io, 0);
    + return 0;
    +
    +cleanup:
    + if (io->first_clone) {
    + dec_pending(io, -ENOMEM);
    + return 0;
    + }
    +
    + /* if no bio has been dispatched yet, we can directly return the error */
    + mempool_free(io, cc->io_pool);
    + return -ENOMEM;
    +}
    +
    +static int crypt_status(struct dm_target *ti, status_type_t type,
    + char *result, unsigned int maxlen)
    +{
    + struct crypt_config *cc = (struct crypt_config *) ti->private;
    + char buffer[32];
    + const char *cipher;
    + const char *mode = NULL;
    + int offset;
    +
    + switch (type) {
    + case STATUSTYPE_INFO:
    + result[0] = '\0';
    + break;
    +
    + case STATUSTYPE_TABLE:
    + cipher = crypto_tfm_alg_name(cc->tfm);
    +
    + switch(cc->tfm->crt_u.cipher.cit_mode) {
    + case CRYPTO_TFM_MODE_CBC:
    + mode = "plain";
    + break;
    + case CRYPTO_TFM_MODE_ECB:
    + mode = "ecb";
    + break;
    + default:
    + BUG();
    + }
    +
    + snprintf(result, maxlen, "%s-%s ", cipher, mode);
    + offset = strlen(result);
    +
    + if (cc->key_size > 0) {
    + if ((maxlen - offset) < ((cc->key_size << 1) + 1))
    + return -ENOMEM;
    +
    + crypt_encode_key(result + offset, cc->key, cc->key_size);
    + offset += cc->key_size << 1;
    + } else {
    + if (offset >= maxlen)
    + return -ENOMEM;
    + result[offset++] = '-';
    + }
    +
    + format_dev_t(buffer, cc->dev->bdev->bd_dev);
    + snprintf(result + offset, maxlen - offset, " " SECTOR_FORMAT
    + " %s " SECTOR_FORMAT, cc->iv_offset,
    + buffer, cc->start);
    + break;
    + }
    + return 0;
    +}
    +
    +static struct target_type crypt_target = {
    + .name = "crypt",
    + .module = THIS_MODULE,
    + .ctr = crypt_ctr,
    + .dtr = crypt_dtr,
    + .map = crypt_map,
    + .status = crypt_status,
    +};
    +
    +static int __init dm_crypt_init(void)
    +{
    + int r;
    +
    + _crypt_io_pool = kmem_cache_create("dm-crypt_io",
    + sizeof(struct crypt_io),
    + 0, 0, NULL, NULL);
    + if (!_crypt_io_pool)
    + return -ENOMEM;
    +
    + _kcryptd_workqueue = create_workqueue("kcryptd");
    + if (!_kcryptd_workqueue) {
    + r = -ENOMEM;
    + DMERR("couldn't create kcryptd");
    + goto bad1;
    + }
    +
    + r = dm_register_target(&crypt_target);
    + if (r < 0) {
    + DMERR("crypt: register failed %d", r);
    + goto bad2;
    + }
    +
    + return 0;
    +
    +bad2:
    + destroy_workqueue(_kcryptd_workqueue);
    +bad1:
    + kmem_cache_destroy(_crypt_io_pool);
    + return r;
    +}
    +
    +static void __exit dm_crypt_exit(void)
    +{
    + int r = dm_unregister_target(&crypt_target);
    +
    + if (r < 0)
    + DMERR("crypt: unregister failed %d", r);
    +
    + destroy_workqueue(_kcryptd_workqueue);
    + kmem_cache_destroy(_crypt_io_pool);
    +}
    +
    +module_init(dm_crypt_init);
    +module_exit(dm_crypt_exit);
    +
    +MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
    +MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
    +MODULE_LICENSE("GPL");
    diff -Nur linux-2.6.3-rc3-mm1.orig/drivers/md/Kconfig linux-2.6.3-rc3-mm1/drivers/md/Kconfig
    --- linux-2.6.3-rc3-mm1.orig/drivers/md/Kconfig 2004-02-10 18:06:13.000000000 +0100
    +++ linux-2.6.3-rc3-mm1/drivers/md/Kconfig 2004-02-16 01:30:51.000000000 +0100
    @@ -170,5 +170,17 @@
    Recent tools use a new version of the ioctl interface, only
    select this option if you intend using such tools.

    +config DM_CRYPT
    + tristate "Crypt target support"
    + depends on BLK_DEV_DM && EXPERIMENTAL
    + select CRYPTO
    + ---help---
    + This device-mapper target allows you to create a device that
    + transparently encrypts the data on it. You'll need to activate
    + the required ciphers in the cryptoapi configuration in order to
    + be able to use it.
    +
    + If unsure, say N.
    +
    endmenu

    diff -Nur linux-2.6.3-rc3-mm1.orig/drivers/md/Makefile linux-2.6.3-rc3-mm1/drivers/md/Makefile
    --- linux-2.6.3-rc3-mm1.orig/drivers/md/Makefile 2004-02-16 01:24:17.000000000 +0100
    +++ linux-2.6.3-rc3-mm1/drivers/md/Makefile 2004-02-16 01:30:51.000000000 +0100
    @@ -23,6 +23,7 @@
    obj-$(CONFIG_MD_MULTIPATH) += multipath.o
    obj-$(CONFIG_BLK_DEV_MD) += md.o
    obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o
    +obj-$(CONFIG_DM_CRYPT) += dm-crypt.o

    quiet_cmd_unroll = UNROLL $@
    cmd_unroll = $(PERL) $(srctree)/$(src)/unroll.pl $(UNROLL) \
    -
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      Last update: 2005-03-22 14:00    [W:0.061 / U:0.692 seconds]
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