1 files changed, 30 insertions, 28 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index b04f98df94ea..835def11419d 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
  * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
- * Copyright (C) 2006-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
  *
  * This file is released under the GPL.
  */
@@ -93,6 +93,8 @@ struct crypt_config {
 
         struct workqueue_struct *io_queue;
         struct workqueue_struct *crypt_queue;
+        wait_queue_head_t writeq;
+
         /*
          * crypto related data
          */
@@ -331,14 +333,7 @@ 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);
-        /*
-         * 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);
+        atomic_set(&ctx->pending, 1);
 }
 
 static int crypt_convert_block(struct crypt_config *cc,
@@ -411,43 +406,42 @@ static void crypt_alloc_req(struct crypt_config *cc,
 static int crypt_convert(struct crypt_config *cc,
                          struct convert_context *ctx)
 {
-        int r = 0;
+        int r;
 
         while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
               ctx->idx_out < ctx->bio_out->bi_vcnt) {
 
                 crypt_alloc_req(cc, ctx);
 
+                atomic_inc(&ctx->pending);
+
                 r = crypt_convert_block(cc, ctx, cc->req);
 
                 switch (r) {
+                /* async */
                 case -EBUSY:
                         wait_for_completion(&ctx->restart);
                         INIT_COMPLETION(ctx->restart);
                         /* fall through*/
                 case -EINPROGRESS:
-                        atomic_inc(&ctx->pending);
                         cc->req = NULL;
-                        r = 0;
-                        /* fall through*/
+                        ctx->sector++;
+                        continue;
+
+                /* sync */
                 case 0:
+                        atomic_dec(&ctx->pending);
                         ctx->sector++;
                         continue;
-                }
 
-                break;
+                /* error */
+                default:
+                        atomic_dec(&ctx->pending);
+                        return r;
+                }
         }
 
-        /*
-         * 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;
+        return 0;
 }
 
 static void dm_crypt_bio_destructor(struct bio *bio)
@@ -624,8 +618,10 @@ static void kcryptd_io_read(struct dm_crypt_io *io)
 static void kcryptd_io_write(struct dm_crypt_io *io)
 {
         struct bio *clone = io->ctx.bio_out;
+        struct crypt_config *cc = io->target->private;
 
         generic_make_request(clone);
+        wake_up(&cc->writeq);
 }
 
 static void kcryptd_io(struct work_struct *work)
@@ -698,7 +694,8 @@ static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
 
                 r = crypt_convert(cc, &io->ctx);
 
-                if (r != -EINPROGRESS) {
+                if (atomic_dec_and_test(&io->ctx.pending)) {
+                        /* processed, no running async crypto  */
                         kcryptd_crypt_write_io_submit(io, r, 0);
                         if (unlikely(r < 0))
                                 return;
@@ -706,8 +703,12 @@ static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
                         atomic_inc(&io->pending);
 
                 /* out of memory -> run queues */
-                if (unlikely(remaining))
+                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);
+                }
         }
 }
 
@@ -746,7 +747,7 @@ static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
 
         r = crypt_convert(cc, &io->ctx);
 
-        if (r != -EINPROGRESS)
+        if (atomic_dec_and_test(&io->ctx.pending))
                 kcryptd_crypt_read_done(io, r);
 
         crypt_dec_pending(io);
@@ -1047,6 +1048,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                 goto bad_crypt_queue;
         }
 
+        init_waitqueue_head(&cc->writeq);
         ti->private = cc;
         return 0;