1 files changed, 66 insertions, 43 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 1395643..682ef9e 100644
--- 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) {
 
@@ -456,9 +457,11 @@ static void dm_crypt_bio_destructor(struct bio *bio)
 /*
  * Generate a new unfragmented bio with the given size
  * This should never violate the device limitations
- * May return a smaller bio when running out of pages
+ * May return a smaller bio when running out of pages, indicated by
+ * *out_of_pages set to 1.
  */
-static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
+static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
+				      unsigned *out_of_pages)
 {
 	struct crypt_config *cc = io->target->private;
 	struct bio *clone;
@@ -472,11 +475,14 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
 		return NULL;
 
 	clone_init(io, clone);
+	*out_of_pages = 0;
 
 	for (i = 0; i < nr_iovecs; i++) {
 		page = mempool_alloc(cc->page_pool, gfp_mask);
-		if (!page)
+		if (!page) {
+			*out_of_pages = 1;
 			break;
+		}
 
 		/*
 		 * if additional pages cannot be allocated without waiting,
@@ -517,6 +523,27 @@ static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
 	}
 }
 
+static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
+					  struct bio *bio, sector_t sector)
+{
+	struct crypt_config *cc = ti->private;
+	struct dm_crypt_io *io;
+
+	io = mempool_alloc(cc->io_pool, GFP_NOIO);
+	io->target = ti;
+	io->base_bio = bio;
+	io->sector = sector;
+	io->error = 0;
+	atomic_set(&io->pending, 0);
+
+	return io;
+}
+
+static void crypt_inc_pending(struct dm_crypt_io *io)
+{
+	atomic_inc(&io->pending);
+}
+
 /*
  * One of the bios was finished. Check for completion of
  * the whole request and correctly clean up the buffer.
@@ -591,7 +618,7 @@ static void kcryptd_io_read(struct dm_crypt_io *io)
 	struct bio *base_bio = io->base_bio;
 	struct bio *clone;
 
-	atomic_inc(&io->pending);
+	crypt_inc_pending(io);
 
 	/*
 	 * The block layer might modify the bvec array, so always
@@ -653,6 +680,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
 		crypt_free_buffer_pages(cc, clone);
 		bio_put(clone);
 		io->error = -EIO;
+		crypt_dec_pending(io);
 		return;
 	}
 
@@ -664,28 +692,34 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
 
 	if (async)
 		kcryptd_queue_io(io);
-	else {
-		atomic_inc(&io->pending);
+	else
 		generic_make_request(clone);
-	}
 }
 
-static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
+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 out_of_pages = 0;
 	unsigned remaining = io->base_bio->bi_size;
 	int r;
 
 	/*
+	 * Prevent io from disappearing until this function completes.
+	 */
+	crypt_inc_pending(io);
+	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
+
+	/*
 	 * The allocated buffers can be smaller than the whole bio,
 	 * so repeat the whole process until all the data can be handled.
 	 */
 	while (remaining) {
-		clone = crypt_alloc_buffer(io, remaining);
+		clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
 		if (unlikely(!clone)) {
 			io->error = -ENOMEM;
-			return;
+			break;
 		}
 
 		io->ctx.bio_out = clone;
@@ -693,37 +727,32 @@ static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
 
 		remaining -= clone->bi_size;
 
+		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 (unlikely(r < 0))
-				return;
-		} else
-			atomic_inc(&io->pending);
 
-		/* 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);
+			/*
+			 * If there was an error, do not try next fragments.
+			 * For async, error is processed in async handler.
+			 */
+			if (unlikely(r < 0))
+				break;
 		}
-	}
-}
 
-static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
-{
-	struct crypt_config *cc = io->target->private;
-
-	/*
-	 * Prevent io from disappearing until this function completes.
-	 */
-	atomic_inc(&io->pending);
+		/*
+		 * Out of memory -> run queues
+		 * But don't wait if split was due to the io size restriction
+		 */
+		if (unlikely(out_of_pages))
+			congestion_wait(WRITE, HZ/100);
 
-	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
-	kcryptd_crypt_write_convert_loop(io);
+		if (unlikely(remaining))
+			wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
+	}
 
 	crypt_dec_pending(io);
 }
@@ -741,7 +770,7 @@ static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
 	struct crypt_config *cc = io->target->private;
 	int r = 0;
 
-	atomic_inc(&io->pending);
+	crypt_inc_pending(io);
 
 	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
 			   io->sector);
@@ -1108,15 +1137,9 @@ static void crypt_dtr(struct dm_target *ti)
 static int crypt_map(struct dm_target *ti, struct bio *bio,
 		     union map_info *map_context)
 {
-	struct crypt_config *cc = ti->private;
 	struct dm_crypt_io *io;
 
-	io = mempool_alloc(cc->io_pool, GFP_NOIO);
-	io->target = ti;
-	io->base_bio = bio;
-	io->sector = bio->bi_sector - ti->begin;
-	io->error = 0;
-	atomic_set(&io->pending, 0);
+	io = crypt_io_alloc(ti, bio, bio->bi_sector - ti->begin);
 
 	if (bio_data_dir(io->base_bio) == READ)
 		kcryptd_queue_io(io);