From: Milan Broz <mbroz@redhat.com>
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>
---
drivers/md/dm-crypt.c | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+)
Index: linux-2.6.24/drivers/md/dm-crypt.c
===================================================================
--- linux-2.6.24.orig/drivers/md/dm-crypt.c 2008-02-07 13:48:36.000000000 +0000
+++ linux-2.6.24/drivers/md/dm-crypt.c 2008-02-07 13:48:37.000000000 +0000
@@ -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 cr
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_co
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;
}