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vhost: add a single dpdk semaphore

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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: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/459160
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
This commit is contained in:
Darek Stojaczyk 2019-06-24 09:59:37 +02:00 committed by Ben Walker
parent 5fb7330151
commit dad4c43a88
1 changed files with 28 additions and 27 deletions
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55
lib/vhost/vhost.c
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@ -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);