vhost: remove session type checks

When rte_vhost tells us to start a session with given
vid, we lookup the corresponsing session object from
an spdk-internal session list and tell it to start
polling without even specifying any backend. The vsession->vdev->type
checks could only fail as a result of some spdk data
corruption, so replace those with just asserts now. This
code path could have never been hit in our tests anyway.

Change-Id: I97c6cbe7088f338b684d291c93cbc59c44cfdc4e
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/466042
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

lib/vhost/vhost_blk.c

@@ -528,15 +528,7 @@ no_bdev_vdev_worker(void *arg)
 static struct spdk_vhost_blk_session *
 to_blk_session(struct spdk_vhost_session *vsession)
 {
-	if (vsession == NULL) {
+	assert(vsession->vdev->backend == &vhost_blk_device_backend);
-		return NULL;
-	}
-
-	if (vsession->vdev->backend != &vhost_blk_device_backend) {
-		SPDK_ERRLOG("%s: not a vhost-blk device\n", vsession->vdev->name);
-		return NULL;
-	}
-
 	return (struct spdk_vhost_blk_session *)vsession;
 }
 
@@ -580,7 +572,6 @@ _spdk_vhost_session_bdev_remove_cb(struct spdk_vhost_dev *vdev, struct spdk_vhos
 		struct spdk_vhost_blk_dev *bvdev = to_blk_dev(vdev);
 
 		assert(bvdev != NULL);
-
 		spdk_bdev_close(bvdev->bdev_desc);
 		bvdev->bdev_desc = NULL;
 		bvdev->bdev = NULL;
@@ -676,18 +667,10 @@ static int
 spdk_vhost_blk_start_cb(struct spdk_vhost_dev *vdev,
 			struct spdk_vhost_session *vsession, void *unused)
 {
+	struct spdk_vhost_blk_session *bvsession = to_blk_session(vsession);
 	struct spdk_vhost_blk_dev *bvdev;
-	struct spdk_vhost_blk_session *bvsession;
 	int i, rc = 0;
 
-	bvsession = to_blk_session(vsession);
-	if (bvsession == NULL) {
-		SPDK_ERRLOG("%s: trying to start non-blk session as a blk one.\n",
-			    vdev->name);
-		rc = -1;
-		goto out;
-	}
-
 	bvdev = to_blk_dev(vdev);
 	assert(bvdev != NULL);
 	bvsession->bvdev = bvdev;
@@ -783,22 +766,12 @@ static int
 spdk_vhost_blk_stop_cb(struct spdk_vhost_dev *vdev,
 		       struct spdk_vhost_session *vsession, void *unused)
 {
-	struct spdk_vhost_blk_session *bvsession;
+	struct spdk_vhost_blk_session *bvsession = to_blk_session(vsession);
-
-	bvsession = to_blk_session(vsession);
-	if (bvsession == NULL) {
-		SPDK_ERRLOG("Trying to stop non-blk controller as a blk one.\n");
-		goto err;
-	}
 
 	spdk_poller_unregister(&bvsession->requestq_poller);
 	bvsession->stop_poller = spdk_poller_register(destroy_session_poller_cb,
 				 bvsession, 1000);
 	return 0;
-
-err:
-	spdk_vhost_session_stop_done(vsession, -1);
-	return -1;
 }
 
 static int
@@ -815,10 +788,6 @@ spdk_vhost_blk_dump_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_writ
 	struct spdk_vhost_blk_dev *bvdev;
 
 	bvdev = to_blk_dev(vdev);
-	if (bvdev == NULL) {
-		return;
-	}
-
 	assert(bvdev != NULL);
 	spdk_json_write_named_object_begin(w, "block");
 
@@ -840,10 +809,7 @@ spdk_vhost_blk_write_config_json(struct spdk_vhost_dev *vdev, struct spdk_json_w
 	struct spdk_vhost_blk_dev *bvdev;
 
 	bvdev = to_blk_dev(vdev);
-	if (bvdev == NULL) {
+	assert(bvdev != NULL);
-		return;
-	}
-
 	if (!bvdev->bdev) {
 		return;
 	}
@@ -874,11 +840,7 @@ spdk_vhost_blk_get_config(struct spdk_vhost_dev *vdev, uint8_t *config,
 	uint64_t blkcnt;
 
 	bvdev = to_blk_dev(vdev);
-	if (bvdev == NULL) {
+	assert(bvdev != NULL);
-		SPDK_ERRLOG("Trying to get virito_blk configuration failed\n");
-		return -1;
-	}
-
 	bdev = bvdev->bdev;
 	if (bdev == NULL) {
 		/* We can't just return -1 here as this GET_CONFIG message might
@@ -1075,10 +1037,7 @@ spdk_vhost_blk_destroy(struct spdk_vhost_dev *vdev)
 	struct spdk_vhost_blk_dev *bvdev = to_blk_dev(vdev);
 	int rc;
 
-	if (!bvdev) {
+	assert(bvdev != NULL);
-		return -EINVAL;
-	}
-
 	rc = spdk_vhost_dev_unregister(&bvdev->vdev);
 	if (rc != 0) {
 		return rc;

lib/vhost/vhost_scsi.c

@@ -815,15 +815,7 @@ to_scsi_dev(struct spdk_vhost_dev *ctrlr)
 static struct spdk_vhost_scsi_session *
 to_scsi_session(struct spdk_vhost_session *vsession)
 {
-	if (vsession == NULL) {
+	assert(vsession->vdev->backend == &spdk_vhost_scsi_device_backend);
-		return NULL;
-	}
-
-	if (vsession->vdev->backend != &spdk_vhost_scsi_device_backend) {
-		SPDK_ERRLOG("%s: not a vhost-scsi device.\n", vsession->vdev->name);
-		return NULL;
-	}
-
 	return (struct spdk_vhost_scsi_session *)vsession;
 }
 
@@ -855,10 +847,7 @@ spdk_vhost_scsi_dev_remove(struct spdk_vhost_dev *vdev)
 	struct spdk_vhost_scsi_dev *svdev = to_scsi_dev(vdev);
 	int rc, i;
 
-	if (svdev == NULL) {
+	assert(svdev != NULL);
-		return -EINVAL;
-	}
-
 	for (i = 0; i < SPDK_VHOST_SCSI_CTRLR_MAX_DEVS; ++i) {
 		if (svdev->scsi_dev_state[i].dev) {
 			if (vdev->registered) {
@@ -890,7 +879,8 @@ spdk_vhost_scsi_dev_get_tgt(struct spdk_vhost_dev *vdev, uint8_t num)
 
 	assert(num < SPDK_VHOST_SCSI_CTRLR_MAX_DEVS);
 	svdev = to_scsi_dev(vdev);
-	if (svdev == NULL || svdev->scsi_dev_state[num].status != VHOST_SCSI_DEV_PRESENT) {
+	assert(svdev != NULL);
+	if (svdev->scsi_dev_state[num].status != VHOST_SCSI_DEV_PRESENT) {
 		return NULL;
 	}
 
@@ -998,10 +988,7 @@ spdk_vhost_scsi_dev_add_tgt(struct spdk_vhost_dev *vdev, int scsi_tgt_num,
 	const char *bdev_names_list[1];
 
 	svdev = to_scsi_dev(vdev);
-	if (svdev == NULL) {
+	assert(svdev != NULL);
-		return -EINVAL;
-	}
-
 	if (scsi_tgt_num < 0) {
 		for (scsi_tgt_num = 0; scsi_tgt_num < SPDK_VHOST_SCSI_CTRLR_MAX_DEVS; scsi_tgt_num++) {
 			if (svdev->scsi_dev_state[scsi_tgt_num].dev == NULL) {
@@ -1127,10 +1114,7 @@ spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_nu
 	}
 
 	svdev = to_scsi_dev(vdev);
-	if (svdev == NULL) {
+	assert(svdev != NULL);
-		return -ENODEV;
-	}
-
 	scsi_dev_state = &svdev->scsi_dev_state[scsi_tgt_num];
 	if (scsi_dev_state->dev == NULL || scsi_dev_state->status == VHOST_SCSI_DEV_ADDING) {
 		SPDK_ERRLOG("%s: SCSI target %u is not occupied\n", vdev->name, scsi_tgt_num);
@@ -1296,16 +1280,12 @@ static int
 spdk_vhost_scsi_start_cb(struct spdk_vhost_dev *vdev,
 			 struct spdk_vhost_session *vsession, void *unused)
 {
-	struct spdk_vhost_scsi_dev *svdev;
+	struct spdk_vhost_scsi_session *svsession = to_scsi_session(vsession);
-	struct spdk_vhost_scsi_session *svsession;
+	struct spdk_vhost_scsi_dev *svdev = svsession->svdev;
 	struct spdk_scsi_dev_vhost_state *state;
 	uint32_t i;
 	int rc;
 
-	svsession = to_scsi_session(vsession);
-	assert(svsession != NULL);
-	svdev = svsession->svdev;
-
 	/* validate all I/O queues are in a contiguous index range */
 	for (i = VIRTIO_SCSI_REQUESTQ; i < vsession->max_queues; i++) {
 		if (vsession->virtqueue[i].vring.desc == NULL) {
@@ -1360,17 +1340,10 @@ out:
 static int
 spdk_vhost_scsi_start(struct spdk_vhost_session *vsession)
 {
-	struct spdk_vhost_scsi_session *svsession;
+	struct spdk_vhost_scsi_session *svsession = to_scsi_session(vsession);
 	struct spdk_vhost_scsi_dev *svdev;
 	int rc;
 
-	svsession = to_scsi_session(vsession);
-	if (svsession == NULL) {
-		SPDK_ERRLOG("%s: trying to start non-scsi session as a scsi one.\n",
-			    vsession->name);
-		return -1;
-	}
-
 	svdev = to_scsi_dev(vsession->vdev);
 	assert(svdev != NULL);
 	svsession->svdev = svdev;
@@ -1450,10 +1423,7 @@ static int
 spdk_vhost_scsi_stop_cb(struct spdk_vhost_dev *vdev,
 			struct spdk_vhost_session *vsession, void *unused)
 {
-	struct spdk_vhost_scsi_session *svsession;
+	struct spdk_vhost_scsi_session *svsession = to_scsi_session(vsession);
-
-	svsession = to_scsi_session(vsession);
-	assert(svsession != NULL);
 
 	/* Stop receiving new I/O requests */
 	spdk_poller_unregister(&svsession->requestq_poller);
@@ -1476,14 +1446,9 @@ spdk_vhost_scsi_stop_cb(struct spdk_vhost_dev *vdev,
 static int
 spdk_vhost_scsi_stop(struct spdk_vhost_session *vsession)
 {
-	struct spdk_vhost_scsi_session *svsession;
+	struct spdk_vhost_scsi_session *svsession = to_scsi_session(vsession);
 	int rc;
 
-	svsession = to_scsi_session(vsession);
-	if (svsession == NULL) {
-		SPDK_ERRLOG("Trying to stop non-scsi session as a scsi one.\n");
-		return -1;
-	}
 	rc = spdk_vhost_session_send_event(vsession->poll_group, vsession,
 					   spdk_vhost_scsi_stop_cb, 3, "stop session");
 	if (rc != 0) {
@@ -1552,10 +1517,6 @@ spdk_vhost_scsi_write_config_json(struct spdk_vhost_dev *vdev, struct spdk_json_
 	struct spdk_scsi_lun *lun;
 	uint32_t i;
 
-	if (to_scsi_dev(vdev) == NULL) {
-		return;
-	}
-
 	spdk_json_write_object_begin(w);
 	spdk_json_write_named_string(w, "method", "construct_vhost_scsi_controller");