virtio-mem: print debug messages from virtio_mem_send_*_request()

Let's move the existing dev_dbg() into the functions, print if something
went wrong, and also print for virtio_mem_send_unplug_all_request().
Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20201112133815.13332-8-david@redhat.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_mem.c

@@ -869,23 +869,33 @@ static int virtio_mem_send_plug_request(struct virtio_mem *vm, uint64_t addr,
 		.u.plug.addr = cpu_to_virtio64(vm->vdev, addr),
 		.u.plug.nb_blocks = cpu_to_virtio16(vm->vdev, nb_vm_blocks),
 	};
+	int rc = -ENOMEM;
 
 	if (atomic_read(&vm->config_changed))
 		return -EAGAIN;
 
+	dev_dbg(&vm->vdev->dev, "plugging memory: 0x%llx - 0x%llx\n", addr,
+		addr + size - 1);
+
 	switch (virtio_mem_send_request(vm, &req)) {
 	case VIRTIO_MEM_RESP_ACK:
 		vm->plugged_size += size;
 		return 0;
 	case VIRTIO_MEM_RESP_NACK:
-		return -EAGAIN;
+		rc = -EAGAIN;
+		break;
 	case VIRTIO_MEM_RESP_BUSY:
-		return -ETXTBSY;
+		rc = -ETXTBSY;
+		break;
 	case VIRTIO_MEM_RESP_ERROR:
-		return -EINVAL;
+		rc = -EINVAL;
+		break;
 	default:
-		return -ENOMEM;
+		break;
 	}
+
+	dev_dbg(&vm->vdev->dev, "plugging memory failed: %d\n", rc);
+	return rc;
 }
 
 static int virtio_mem_send_unplug_request(struct virtio_mem *vm, uint64_t addr,
@@ -897,21 +907,30 @@ static int virtio_mem_send_unplug_request(struct virtio_mem *vm, uint64_t addr,
 		.u.unplug.addr = cpu_to_virtio64(vm->vdev, addr),
 		.u.unplug.nb_blocks = cpu_to_virtio16(vm->vdev, nb_vm_blocks),
 	};
+	int rc = -ENOMEM;
 
 	if (atomic_read(&vm->config_changed))
 		return -EAGAIN;
 
+	dev_dbg(&vm->vdev->dev, "unplugging memory: 0x%llx - 0x%llx\n", addr,
+		addr + size - 1);
+
 	switch (virtio_mem_send_request(vm, &req)) {
 	case VIRTIO_MEM_RESP_ACK:
 		vm->plugged_size -= size;
 		return 0;
 	case VIRTIO_MEM_RESP_BUSY:
-		return -ETXTBSY;
+		rc = -ETXTBSY;
+		break;
 	case VIRTIO_MEM_RESP_ERROR:
-		return -EINVAL;
+		rc = -EINVAL;
+		break;
 	default:
-		return -ENOMEM;
+		break;
 	}
+
+	dev_dbg(&vm->vdev->dev, "unplugging memory failed: %d\n", rc);
+	return rc;
 }
 
 static int virtio_mem_send_unplug_all_request(struct virtio_mem *vm)
@@ -919,6 +938,9 @@ static int virtio_mem_send_unplug_all_request(struct virtio_mem *vm)
 	const struct virtio_mem_req req = {
 		.type = cpu_to_virtio16(vm->vdev, VIRTIO_MEM_REQ_UNPLUG_ALL),
 	};
+	int rc = -ENOMEM;
+
+	dev_dbg(&vm->vdev->dev, "unplugging all memory");
 
 	switch (virtio_mem_send_request(vm, &req)) {
 	case VIRTIO_MEM_RESP_ACK:
@@ -928,10 +950,14 @@ static int virtio_mem_send_unplug_all_request(struct virtio_mem *vm)
 		atomic_set(&vm->config_changed, 1);
 		return 0;
 	case VIRTIO_MEM_RESP_BUSY:
-		return -ETXTBSY;
+		rc = -ETXTBSY;
+		break;
 	default:
-		return -ENOMEM;
+		break;
 	}
+
+	dev_dbg(&vm->vdev->dev, "unplugging all memory failed: %d\n", rc);
+	return rc;
 }
 
 /*
@@ -946,9 +972,6 @@ static int virtio_mem_mb_plug_sb(struct virtio_mem *vm, unsigned long mb_id,
 	const uint64_t size = count * vm->subblock_size;
 	int rc;
 
-	dev_dbg(&vm->vdev->dev, "plugging memory block: %lu : %i - %i\n", mb_id,
-		sb_id, sb_id + count - 1);
-
 	rc = virtio_mem_send_plug_request(vm, addr, size);
 	if (!rc)
 		virtio_mem_mb_set_sb_plugged(vm, mb_id, sb_id, count);
@@ -967,9 +990,6 @@ static int virtio_mem_mb_unplug_sb(struct virtio_mem *vm, unsigned long mb_id,
 	const uint64_t size = count * vm->subblock_size;
 	int rc;
 
-	dev_dbg(&vm->vdev->dev, "unplugging memory block: %lu : %i - %i\n",
-		mb_id, sb_id, sb_id + count - 1);
-
 	rc = virtio_mem_send_unplug_request(vm, addr, size);
 	if (!rc)
 		virtio_mem_mb_set_sb_unplugged(vm, mb_id, sb_id, count);