Commit 376d893a authored by Darek Stojaczyk's avatar Darek Stojaczyk Committed by Jim Harris
Browse files

vhost: introduce vsession->started 



We used to rely on lcore >= 0 for sessions that are
started (have their pollers running) and in order to
prevent data races, that lcore field had to be set from
the same thread that runs the pollers, directly after
registering/unregistering them. The lcore was always
set to spdk_env_get_current_core(), but we won't be able
to use an equivalent get_current_poll_group() function
after we switch to poll groups. We will have a poll group
object only inside spdk_vhost_session_send_event() that's
called from the DPDK rte_vhost thread.

In order to change the lcore field (or a poll group one)
from spdk_vhost_session_send_event(), we'll need a separate
field to maintain the started/stopped status that's only
going to be modified from the session's thread.

Change-Id: Idb09cae3c4715eebb20282aad203987b26be707b
Signed-off-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/452394


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
parent 838949ea

lib/vhost/rte_vhost_compat.c

+4 −4
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ spdk_extern_vhost_pre_msg_handler(int vid, void *_msg) 


	switch (msg->request) {

	case VHOST_USER_GET_VRING_BASE:

		if (vsession->forced_polling && vsession->lcore != -1) {

		if (vsession->forced_polling && vsession->started) {

			/* Our queue is stopped for whatever reason, but we may still

			 * need to poll it after it's initialized again.

			 */
@@ -77,7 +77,7 @@ spdk_extern_vhost_pre_msg_handler(int vid, void *_msg) 
	case VHOST_USER_SET_VRING_ADDR:

	case VHOST_USER_SET_VRING_NUM:

	case VHOST_USER_SET_VRING_KICK:

		if (vsession->forced_polling && vsession->lcore != -1) {

		if (vsession->forced_polling && vsession->started) {

			/* Additional queues are being initialized, so we either processed

			 * enough I/Os and are switching from SeaBIOS to the OS now, or

			 * we were never in SeaBIOS in the first place. Either way, we
@@ -105,7 +105,7 @@ spdk_extern_vhost_pre_msg_handler(int vid, void *_msg) 
		 * We will start the device again from the post-processing

		 * message handler.

		 */

		if (vsession->lcore != -1) {

		if (vsession->started) {

			g_spdk_vhost_ops.destroy_device(vid);

			vsession->needs_restart = true;

		}
@@ -187,7 +187,7 @@ spdk_extern_vhost_post_msg_handler(int vid, void *_msg) 
		/* vhost-user spec tells us to start polling a queue after receiving

		 * its SET_VRING_KICK message. Let's do it!

		 */

		if (vsession->forced_polling && vsession->lcore == -1) {

		if (vsession->forced_polling && !vsession->started) {

			g_spdk_vhost_ops.new_device(vid);

		}

		break;

lib/vhost/vhost.c

+8 −5
Original line number Diff line number Diff line
@@ -899,6 +899,7 @@ spdk_vhost_session_start_done(struct spdk_vhost_session *vsession, int response) 
{

	if (response == 0) {

		vsession->lcore = spdk_env_get_current_core();

		vsession->started = true;

		assert(vsession->vdev->active_session_num < UINT32_MAX);

		vsession->vdev->active_session_num++;

	}
@@ -910,6 +911,7 @@ spdk_vhost_session_stop_done(struct spdk_vhost_session *vsession, int response) 
{

	if (response == 0) {

		vsession->lcore = -1;

		vsession->started = false;

		assert(vsession->vdev->active_session_num > 0);

		vsession->vdev->active_session_num--;

	}
@@ -963,7 +965,7 @@ spdk_vhost_event_async_foreach_fn(void *arg1, void *arg2) 
		goto out_unlock_continue;

	}



	if (vsession->lcore >= 0 &&

	if (vsession->started &&

	    (uint32_t)vsession->lcore != spdk_env_get_current_core()) {

		/* if session has been relocated to other core, it is no longer thread-safe

		 * to access its contents here. Even though we're running under the global
@@ -1099,7 +1101,7 @@ stop_device(int vid) 
		return;

	}



	if (vsession->lcore == -1) {

	if (!vsession->started) {

		/* already stopped, nothing to do */

		pthread_mutex_unlock(&g_spdk_vhost_mutex);

		return;
@@ -1126,7 +1128,7 @@ start_device(int vid) 
	}



	vdev = vsession->vdev;

	if (vsession->lcore != -1) {

	if (vsession->started) {

		/* already started, nothing to do */

		rc = 0;

		goto out;
@@ -1345,6 +1347,7 @@ new_connection(int vid) 
	vsession->id = vdev->vsessions_num++;

	vsession->vid = vid;

	vsession->lcore = -1;

	vsession->started = false;

	vsession->initialized = false;

	vsession->next_stats_check_time = 0;

	vsession->stats_check_interval = SPDK_VHOST_STATS_CHECK_INTERVAL_MS *
@@ -1369,7 +1372,7 @@ destroy_connection(int vid) 
		return;

	}



	if (vsession->lcore != -1) {

	if (vsession->started) {

		_stop_session(vsession);

	}
@@ -1389,7 +1392,7 @@ spdk_vhost_external_event_foreach_continue(struct spdk_vhost_dev *vdev, 
		goto out_finish_foreach;

	}



	while (vsession->lcore == -1) {

	while (!vsession->started) {

		if (vsession->initialized) {

			rc = fn(vdev, vsession, arg);

			if (rc < 0) {

lib/vhost/vhost_internal.h

+1 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ struct spdk_vhost_session { 
	int32_t lcore;



	bool initialized;

	bool started;

	bool needs_restart;

	bool forced_polling;

lib/vhost/vhost_scsi.c

+2 −2
Original line number Diff line number Diff line
@@ -947,7 +947,7 @@ spdk_vhost_scsi_session_add_tgt(struct spdk_vhost_dev *vdev, 


	svsession = (struct spdk_vhost_scsi_session *)vsession;

	session_sdev = &svsession->scsi_dev_state[scsi_tgt_num];

	if (vsession->lcore == -1 || session_sdev->dev != NULL) {

	if (!vsession->started || session_sdev->dev != NULL) {

		/* Nothing to do. */

		return 0;

	}
@@ -1092,7 +1092,7 @@ spdk_vhost_scsi_session_remove_tgt(struct spdk_vhost_dev *vdev, 
	svsession = (struct spdk_vhost_scsi_session *)vsession;

	state = &svsession->scsi_dev_state[scsi_tgt_num];



	if (vsession->lcore == -1 || state->dev == NULL) {

	if (!vsession->started || state->dev == NULL) {

		/* Nothing to do */

		return 0;

	}

test/unit/lib/vhost/vhost.c/vhost_ut.c

+1 −0
Original line number Diff line number Diff line
@@ -164,6 +164,7 @@ start_vdev(struct spdk_vhost_dev *vdev) 
	CU_ASSERT(rc == 0);

	SPDK_CU_ASSERT_FATAL(vsession != NULL);

	vsession->lcore = 0;

	vsession->started = true;

	vsession->vid = 0;

	vsession->mem = mem;

	TAILQ_INSERT_TAIL(&vdev->vsessions, vsession, tailq);