3 files changed, 23 insertions, 6 deletions

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index d6c821d48090..51bfd7737552 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1369,10 +1369,13 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
 	}
 
 	if (dev->zoned)
-		cmd->error = null_process_zoned_cmd(cmd, op,
-						    sector, nr_sectors);
+		sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
 	else
-		cmd->error = null_process_cmd(cmd, op, sector, nr_sectors);
+		sts = null_process_cmd(cmd, op, sector, nr_sectors);
+
+	/* Do not overwrite errors (e.g. timeout errors) */
+	if (cmd->error == BLK_STS_OK)
+		cmd->error = sts;
 
 out:
 	nullb_complete_cmd(cmd);
@@ -1451,8 +1454,20 @@ static bool should_requeue_request(struct request *rq)
 
 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
 {
+	struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+
 	pr_info("rq %p timed out\n", rq);
-	blk_mq_complete_request(rq);
+
+	/*
+	 * If the device is marked as blocking (i.e. memory backed or zoned
+	 * device), the submission path may be blocked waiting for resources
+	 * and cause real timeouts. For these real timeouts, the submission
+	 * path will complete the request using blk_mq_complete_request().
+	 * Only fake timeouts need to execute blk_mq_complete_request() here.
+	 */
+	cmd->error = BLK_STS_TIMEOUT;
+	if (cmd->fake_timeout)
+		blk_mq_complete_request(rq);
 	return BLK_EH_DONE;
 }
 
@@ -1473,6 +1488,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 	cmd->rq = bd->rq;
 	cmd->error = BLK_STS_OK;
 	cmd->nq = nq;
+	cmd->fake_timeout = should_timeout_request(bd->rq);
 
 	blk_mq_start_request(bd->rq);
 
@@ -1489,7 +1505,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 			return BLK_STS_OK;
 		}
 	}
-	if (should_timeout_request(bd->rq))
+	if (cmd->fake_timeout)
 		return BLK_STS_OK;
 
 	return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
index 83504f3cc9d6..4876d5adb12d 100644
--- a/drivers/block/null_blk/null_blk.h
+++ b/drivers/block/null_blk/null_blk.h
@@ -22,6 +22,7 @@ struct nullb_cmd {
 	blk_status_t error;
 	struct nullb_queue *nq;
 	struct hrtimer timer;
+	bool fake_timeout;
 };
 
 struct nullb_queue {
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 1cdf09ff67b6..14e452896d04 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -891,7 +891,7 @@ next:
 out:
 	for (i = last_map; i < num; i++) {
 		/* Don't zap current batch's valid persistent grants. */
-		if(i >= last_map + segs_to_map)
+		if(i >= map_until)
 			pages[i]->persistent_gnt = NULL;
 		pages[i]->handle = BLKBACK_INVALID_HANDLE;
 	}