dm crypt: tidy ctx pending

Move the initialisation of ctx->pending into one place, at the
start of crypt_convert().

Introduce crypt_finished to indicate whether or not the encryption
is finished, for use in a later patch.

No functional change.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 262ed18..f6018f5 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -333,7 +333,6 @@ static void crypt_convert_init(struct crypt_config *cc,
        ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
        ctx->sector = sector + cc->iv_offset;
        init_completion(&ctx->restart);
-       atomic_set(&ctx->pending, 1);
 }
 
 static int crypt_convert_block(struct crypt_config *cc,
@@ -408,6 +407,8 @@ static int crypt_convert(struct crypt_config *cc,
 {
        int r;
 
+       atomic_set(&ctx->pending, 1);
+
        while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
              ctx->idx_out < ctx->bio_out->bi_vcnt) {
 
@@ -694,6 +695,7 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
 {
        struct crypt_config *cc = io->target->private;
        struct bio *clone;
+       int crypt_finished;
        unsigned remaining = io->base_bio->bi_size;
        int r;
 
@@ -721,19 +723,23 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
 
                crypt_inc_pending(io);
                r = crypt_convert(cc, &io->ctx);
+               crypt_finished = atomic_dec_and_test(&io->ctx.pending);
 
-               if (atomic_dec_and_test(&io->ctx.pending)) {
-                       /* processed, no running async crypto  */
+               /* Encryption was already finished, submit io now */
+               if (crypt_finished) {
                        kcryptd_crypt_write_io_submit(io, r, 0);
+
+                       /*
+                        * If there was an error, do not try next fragments.
+                        * For async, error is processed in async handler.
+                        */
                        if (unlikely(r < 0))
                                break;
                }
 
                /* out of memory -> run queues */
                if (unlikely(remaining)) {
-                       /* wait for async crypto then reinitialize pending */
                        wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
-                       atomic_set(&io->ctx.pending, 1);
                        congestion_wait(WRITE, HZ/100);
                }
        }