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vhost: ignore sessions that weren't ever started

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The previous patches described as optimizations also
fixed some issues. They seem sufficient to cover all
the error cases, but the real source of the problem
lies in foreach_session() initiated by the device backend,
which can use sessions that were never seen by the
backend.

The backends are only notified when a session is
*started*, but foreach_session() iterates through
all the sessions - even those that were never started.
Vhost SCSI, for example, in the foreach_session() callbacks
used to expect svsession->svdev to be always set, but
that field is only set when the session gets started.

A perfect solution would to introduce a new backend
callback to be called on new connection. Vhost SCSI
could set e.g. svsession->svdev inside. For now we go
with much easier solution that prevents sessions from
being used in foreach-session() unless they were
started at least once. (...and e.g. got their ->svdev set)

Change-Id: Ida30a1f27f99977360d08a71a64fc92931b25b75
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/449394
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
This commit is contained in:
Darek Stojaczyk 2019-03-27 14:59:45 +01:00 committed by Jim Harris
parent bf77d4b774
commit e051a5366e
2 changed files with 10 additions and 4 deletions
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7
lib/vhost/vhost.c
View File

@ -943,7 +943,7 @@ spdk_vhost_event_async_foreach_fn(void *arg1, void *arg2)
}
vsession = spdk_vhost_session_find_by_id(vdev, ctx->vsession_id);
if (vsession == NULL) {
if (vsession == NULL || !vsession->initialized) {
/* The session must have been removed in the meantime, so we
* just skip it in our foreach chain
*/
@ -1183,6 +1183,7 @@ start_device(int vid)
spdk_vhost_session_set_coalescing(vdev, vsession, NULL);
spdk_vhost_session_mem_register(vsession);
vsession->initialized = true;
rc = vdev->backend->start_session(vsession);
if (rc != 0) {
spdk_vhost_session_mem_unregister(vsession);
@ -1346,6 +1347,7 @@ new_connection(int vid)
vsession->id = vdev->vsessions_num++;
vsession->vid = vid;
vsession->lcore = -1;
vsession->initialized = false;
vsession->next_stats_check_time = 0;
vsession->stats_check_interval = SPDK_VHOST_STATS_CHECK_INTERVAL_MS *
spdk_get_ticks_hz() / 1000UL;
@ -1390,10 +1392,13 @@ spdk_vhost_external_event_foreach_continue(struct spdk_vhost_dev *vdev,
}
while (vsession->lcore == -1) {
if (vsession->initialized) {
rc = fn(vdev, vsession, arg);
if (rc < 0) {
return;
}
}
vsession = spdk_vhost_session_next(vdev, vsession->id);
if (vsession == NULL) {
goto out_finish_foreach;

1
lib/vhost/vhost_internal.h
View File

@ -126,6 +126,7 @@ struct spdk_vhost_session {
int32_t lcore;
bool initialized;
bool needs_restart;
bool forced_polling;