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dm crypt: add completion for async 

dm-crypt: Use crypto ablkcipher interface
Prepare completion for async crypto request.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz 2008-02-08 02:11:09 +00:00 committed by Alasdair G Kergon
parent ddd42edfd8
commit 43d6903482
1 changed files with 21 additions and 0 deletions
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21
drivers/md/dm-crypt.c
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@ -6,6 +6,7 @@
* This file is released under the GPL.
*/
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
@ -31,6 +32,7 @@
* context holding the current state of a multi-part conversion
*/
struct convert_context {
struct completion restart;
struct bio *bio_in;
struct bio *bio_out;
unsigned int offset_in;
@ -38,6 +40,7 @@ struct convert_context {
unsigned int idx_in;
unsigned int idx_out;
sector_t sector;
atomic_t pending;
};
/*
@ -359,6 +362,15 @@ static void crypt_convert_init(struct crypt_config *cc,
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;
init_completion(&ctx->restart);
/*
* Crypto operation can be asynchronous,
* ctx->pending is increased after request submission.
* We need to ensure that we don't call the crypt finish
* operation before pending got incremented
* (dependent on crypt submission return code).
*/
atomic_set(&ctx->pending, 2);
}
static int crypt_convert_block(struct crypt_config *cc,
@ -418,6 +430,15 @@ static int crypt_convert(struct crypt_config *cc,
ctx->sector++;
}
/*
* If there are pending crypto operation run async
* code. Otherwise process return code synchronously.
* The step of 2 ensures that async finish doesn't
* call crypto finish too early.
*/
if (atomic_sub_return(2, &ctx->pending))
return -EINPROGRESS;
return r;
}