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e7cd2514ea
This patch makes chainiv avoid spinning by postponing requests on lock contention if the user allows the use of asynchronous algorithms. If a synchronous algorithm is requested then we behave as before. This should improve IPsec performance on SMP when two CPUs attempt to transmit over the same SA. Currently one of them will spin doing nothing waiting for the other CPU to finish its encryption. This patch makes it postpone the request and get on with other work. If only one CPU is transmitting for a given SA, then we will process the request synchronously as before. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
332 lines
8.0 KiB
C
332 lines
8.0 KiB
C
/*
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* chainiv: Chain IV Generator
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*
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* Generate IVs simply be using the last block of the previous encryption.
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* This is mainly useful for CBC with a synchronous algorithm.
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/internal/skcipher.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/workqueue.h>
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enum {
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CHAINIV_STATE_INUSE = 0,
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};
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struct chainiv_ctx {
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spinlock_t lock;
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char iv[];
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};
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struct async_chainiv_ctx {
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unsigned long state;
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spinlock_t lock;
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int err;
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struct crypto_queue queue;
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struct work_struct postponed;
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char iv[];
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};
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static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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unsigned int ivsize;
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int err;
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ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
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ablkcipher_request_set_callback(subreq, req->creq.base.flags &
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~CRYPTO_TFM_REQ_MAY_SLEEP,
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req->creq.base.complete,
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req->creq.base.data);
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ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
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req->creq.nbytes, req->creq.info);
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spin_lock_bh(&ctx->lock);
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ivsize = crypto_ablkcipher_ivsize(geniv);
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memcpy(req->giv, ctx->iv, ivsize);
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memcpy(subreq->info, ctx->iv, ivsize);
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err = crypto_ablkcipher_encrypt(subreq);
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if (err)
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goto unlock;
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memcpy(ctx->iv, subreq->info, ivsize);
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unlock:
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spin_unlock_bh(&ctx->lock);
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return err;
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}
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static int chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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spin_lock_bh(&ctx->lock);
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if (crypto_ablkcipher_crt(geniv)->givencrypt !=
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chainiv_givencrypt_first)
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goto unlock;
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crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
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get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
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unlock:
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spin_unlock_bh(&ctx->lock);
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return chainiv_givencrypt(req);
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}
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static int chainiv_init_common(struct crypto_tfm *tfm)
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{
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tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
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return skcipher_geniv_init(tfm);
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}
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static int chainiv_init(struct crypto_tfm *tfm)
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{
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struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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spin_lock_init(&ctx->lock);
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return chainiv_init_common(tfm);
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}
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static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
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{
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int queued;
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if (!ctx->queue.qlen) {
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smp_mb__before_clear_bit();
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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if (!ctx->queue.qlen ||
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test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto out;
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}
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queued = schedule_work(&ctx->postponed);
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BUG_ON(!queued);
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out:
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return ctx->err;
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}
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static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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int err;
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spin_lock_bh(&ctx->lock);
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err = skcipher_enqueue_givcrypt(&ctx->queue, req);
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spin_unlock_bh(&ctx->lock);
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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return err;
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ctx->err = err;
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return async_chainiv_schedule_work(ctx);
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}
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static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
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memcpy(req->giv, ctx->iv, ivsize);
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memcpy(subreq->info, ctx->iv, ivsize);
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ctx->err = crypto_ablkcipher_encrypt(subreq);
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if (ctx->err)
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goto out;
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memcpy(ctx->iv, subreq->info, ivsize);
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out:
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return async_chainiv_schedule_work(ctx);
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}
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static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
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ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
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ablkcipher_request_set_callback(subreq, req->creq.base.flags,
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req->creq.base.complete,
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req->creq.base.data);
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ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
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req->creq.nbytes, req->creq.info);
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto postpone;
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if (ctx->queue.qlen) {
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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goto postpone;
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}
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return async_chainiv_givencrypt_tail(req);
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postpone:
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return async_chainiv_postpone_request(req);
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}
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static int async_chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
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{
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struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
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struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
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if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
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goto out;
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if (crypto_ablkcipher_crt(geniv)->givencrypt !=
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async_chainiv_givencrypt_first)
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goto unlock;
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crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
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get_random_bytes(ctx->iv, crypto_ablkcipher_ivsize(geniv));
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unlock:
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clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
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out:
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return async_chainiv_givencrypt(req);
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}
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static void async_chainiv_do_postponed(struct work_struct *work)
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{
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struct async_chainiv_ctx *ctx = container_of(work,
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struct async_chainiv_ctx,
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postponed);
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struct skcipher_givcrypt_request *req;
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struct ablkcipher_request *subreq;
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/* Only handle one request at a time to avoid hogging keventd. */
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spin_lock_bh(&ctx->lock);
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req = skcipher_dequeue_givcrypt(&ctx->queue);
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spin_unlock_bh(&ctx->lock);
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if (!req) {
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async_chainiv_schedule_work(ctx);
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return;
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}
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subreq = skcipher_givcrypt_reqctx(req);
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subreq->base.flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
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async_chainiv_givencrypt_tail(req);
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}
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static int async_chainiv_init(struct crypto_tfm *tfm)
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{
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struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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spin_lock_init(&ctx->lock);
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crypto_init_queue(&ctx->queue, 100);
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INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
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return chainiv_init_common(tfm);
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}
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static void async_chainiv_exit(struct crypto_tfm *tfm)
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{
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struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
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BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) || ctx->queue.qlen);
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skcipher_geniv_exit(tfm);
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}
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static struct crypto_template chainiv_tmpl;
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static struct crypto_instance *chainiv_alloc(struct rtattr **tb)
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{
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struct crypto_attr_type *algt;
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struct crypto_instance *inst;
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int err;
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algt = crypto_get_attr_type(tb);
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err = PTR_ERR(algt);
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if (IS_ERR(algt))
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return ERR_PTR(err);
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inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
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if (IS_ERR(inst))
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goto out;
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inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;
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inst->alg.cra_init = chainiv_init;
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inst->alg.cra_exit = skcipher_geniv_exit;
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inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
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if (!crypto_requires_sync(algt->type, algt->mask)) {
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inst->alg.cra_flags |= CRYPTO_ALG_ASYNC;
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inst->alg.cra_ablkcipher.givencrypt =
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async_chainiv_givencrypt_first;
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inst->alg.cra_init = async_chainiv_init;
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inst->alg.cra_exit = async_chainiv_exit;
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inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
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}
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inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
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out:
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return inst;
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}
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static struct crypto_template chainiv_tmpl = {
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.name = "chainiv",
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.alloc = chainiv_alloc,
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.free = skcipher_geniv_free,
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.module = THIS_MODULE,
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};
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static int __init chainiv_module_init(void)
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{
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return crypto_register_template(&chainiv_tmpl);
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}
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static void __exit chainiv_module_exit(void)
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{
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crypto_unregister_template(&chainiv_tmpl);
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}
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module_init(chainiv_module_init);
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module_exit(chainiv_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Chain IV Generator");
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