Commit dad4c43a authored by Darek Stojaczyk's avatar Darek Stojaczyk Committed by Ben Walker
Browse files

vhost: add a single dpdk semaphore 



The semaphore was a part of struct spdk_vhost_session_fn_ctx
so far, but since there's only one pthread waiting on that
semaphore and hence only one event using it, we could just
use a single global sem_t. Same thing with response code
for those callbacks - there's only one needed.

Going a step further, the function complete_session_event()
was removed - it would only operate on global variables now,
and its signature wouldn't make much sense after this
refactor, so it's been inlined.

This serves as cleanup.

Change-Id: I63ef41d7e1564fff5e785de101d887bc1014aad9
Signed-off-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/459160


Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 5fb73301

lib/vhost/vhost.c

+28 −27
Original line number Diff line number Diff line
@@ -62,6 +62,16 @@ static struct spdk_thread *g_vhost_init_thread; 


static spdk_vhost_fini_cb g_fini_cpl_cb;



/**

 * DPDK calls our callbacks synchronously but the work those callbacks

 * perform needs to be async. Luckily, all DPDK callbacks are called on

 * a DPDK-internal pthread, so we'll just wait on a semaphore in there.

 */

static sem_t g_dpdk_sem;



/** Return code for the current DPDK callback */

static int g_dpdk_response;



struct spdk_vhost_session_fn_ctx {

	/** Device pointer obtained before enqueuing the event */

	struct spdk_vhost_dev *vdev;
@@ -72,12 +82,6 @@ struct spdk_vhost_session_fn_ctx { 
	/** User callback function to be executed on given thread. */

	spdk_vhost_session_fn cb_fn;



	/** Semaphore used to signal that event is done. */

	sem_t sem;



	/** Response to be written by enqueued event. */

	int response;



	/** Custom user context */

	void *user_ctx;

};
@@ -891,15 +895,6 @@ spdk_vhost_put_poll_group(struct vhost_poll_group *pg) 
	pg->ref--;

}



static void

complete_session_event(struct spdk_vhost_session *vsession, int response)

{

	struct spdk_vhost_session_fn_ctx *ctx = vsession->event_ctx;



	ctx->response = response;

	sem_post(&ctx->sem);

}



void

spdk_vhost_session_start_done(struct spdk_vhost_session *vsession, int response)

{
@@ -908,7 +903,9 @@ spdk_vhost_session_start_done(struct spdk_vhost_session *vsession, int response) 
		assert(vsession->vdev->active_session_num < UINT32_MAX);

		vsession->vdev->active_session_num++;

	}

	complete_session_event(vsession, response);



	g_dpdk_response = response;

	sem_post(&g_dpdk_sem);

}



void
@@ -919,7 +916,9 @@ spdk_vhost_session_stop_done(struct spdk_vhost_session *vsession, int response) 
		assert(vsession->vdev->active_session_num > 0);

		vsession->vdev->active_session_num--;

	}

	complete_session_event(vsession, response);



	g_dpdk_response = response;

	sem_post(&g_dpdk_sem);

}



static void
@@ -1000,12 +999,6 @@ spdk_vhost_session_send_event(struct vhost_poll_group *pg, 
	struct timespec timeout;

	int rc;



	rc = sem_init(&ev_ctx.sem, 0, 0);

	if (rc != 0) {

		SPDK_ERRLOG("Failed to initialize semaphore for vhost timed event\n");

		return -errno;

	}



	ev_ctx.vdev = vsession->vdev;

	ev_ctx.vsession_id = vsession->id;

	ev_ctx.cb_fn = cb_fn;
@@ -1018,16 +1011,15 @@ spdk_vhost_session_send_event(struct vhost_poll_group *pg, 
	clock_gettime(CLOCK_REALTIME, &timeout);

	timeout.tv_sec += timeout_sec;



	rc = sem_timedwait(&ev_ctx.sem, &timeout);

	rc = sem_timedwait(&g_dpdk_sem, &timeout);

	if (rc != 0) {

		SPDK_ERRLOG("Timeout waiting for event: %s.\n", errmsg);

		sem_wait(&ev_ctx.sem);

		sem_wait(&g_dpdk_sem);

	}



	sem_destroy(&ev_ctx.sem);

	pthread_mutex_lock(&g_spdk_vhost_mutex);

	vsession->event_ctx = NULL;

	return ev_ctx.response;

	return g_dpdk_response;

}



static int
@@ -1514,6 +1506,14 @@ spdk_vhost_init(spdk_vhost_init_cb init_cb) 
		goto err_out;

	}



	ret = sem_init(&g_dpdk_sem, 0, 0);

	if (ret != 0) {

		SPDK_ERRLOG("Failed to initialize semaphore for rte_vhost pthread.\n");

		spdk_cpuset_free(g_tmp_cpuset);

		ret = -1;

		goto err_out;

	}



	spdk_for_each_thread(vhost_create_poll_group,

			     init_cb,

			     vhost_create_poll_group_done);
@@ -1539,6 +1539,7 @@ _spdk_vhost_fini(void *arg1) 
	spdk_vhost_unlock();



	/* All devices are removed now. */

	sem_destroy(&g_dpdk_sem);

	spdk_cpuset_free(g_tmp_cpuset);

	TAILQ_FOREACH_SAFE(pg, &g_poll_groups, tailq, tpg) {

		TAILQ_REMOVE(&g_poll_groups, pg, tailq);