| Message ID | 20160727050918.12772-1-rajur@chelsio.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Wed, Jul 27, 2016 at 10:39:18AM +0530, Raju Rangoju wrote: > When the low level driver exercises the hot unplug they would call > rdma_cm cma_remove_one which would fire DEVICE_REMOVAL event to all cma > consumers. Now, if consumer doesn't make sure they destroy all IB > objects created on that IB device instance prior to finalizing all > processing of DEVICE_REMOVAL callback, rdma_cm will let the lld to > de-register with IB core and destroy the IB device instance. And if the > consumer calls (say) ib_dereg_mr(), it will crash since that dev object > is NULL. > > In the current implementation, iser-target just initiates the cleanup > and returns from DEVICE_REMOVAL callback. This deferred work creates a > race between iser-target cleaning IB objects(say MR) and lld destroying > IB device instance. > > This patch includes the following fixes > -> make sure that consumer frees all IB objects associated with device > instance > -> return non-zero from the callback to destroy the rdma_cm id > --- > drivers/infiniband/ulp/isert/ib_isert.c | 24 ++++++++++++++++++++++-- > drivers/infiniband/ulp/isert/ib_isert.h | 2 ++ > 2 files changed, 24 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c > index a990c04..9adc38d 100644 > --- a/drivers/infiniband/ulp/isert/ib_isert.c > +++ b/drivers/infiniband/ulp/isert/ib_isert.c > @@ -405,6 +405,7 @@ isert_init_conn(struct isert_conn *isert_conn) > INIT_LIST_HEAD(&isert_conn->node); > init_completion(&isert_conn->login_comp); > init_completion(&isert_conn->login_req_comp); > + init_waitqueue_head(&isert_conn->rem_wait); > kref_init(&isert_conn->kref); > mutex_init(&isert_conn->mutex); > INIT_WORK(&isert_conn->release_work, isert_release_work); > @@ -580,7 +581,8 @@ isert_connect_release(struct isert_conn *isert_conn) > BUG_ON(!device); > > isert_free_rx_descriptors(isert_conn); > - if (isert_conn->cm_id) > + if (isert_conn->cm_id && > + !isert_conn->dev_removed) > rdma_destroy_id(isert_conn->cm_id); > > if (isert_conn->qp) { > @@ -595,7 +597,10 @@ isert_connect_release(struct isert_conn *isert_conn) > > isert_device_put(device); > > - kfree(isert_conn); > + if (isert_conn->dev_removed) > + wake_up_interruptible(&isert_conn->rem_wait); > + else > + kfree(isert_conn); > } > > static void > @@ -755,6 +760,7 @@ static int > isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) > { > struct isert_np *isert_np = cma_id->context; > + struct isert_conn *isert_conn; > int ret = 0; > > isert_info("%s (%d): status %d id %p np %p\n", > @@ -778,6 +784,20 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) > case RDMA_CM_EVENT_DEVICE_REMOVAL: /* FALLTHRU */ > case RDMA_CM_EVENT_TIMEWAIT_EXIT: /* FALLTHRU */ > ret = isert_disconnected_handler(cma_id, event->event); > + > + if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL) { It will be nicer if you can reshuffle cases in original switch in such was that will eliminate the need of this "if". > + isert_conn = cma_id->qp->qp_context; > + isert_conn->dev_removed = true; > + wait_event_interruptible(isert_conn->rem_wait, > + isert_conn->state == ISER_CONN_DOWN); > + > + kfree(isert_conn); > + /* > + * return non-zero from the callback to destroy > + * the rdma cm id > + */ > + return 1; > + } > break; > case RDMA_CM_EVENT_REJECTED: /* FALLTHRU */ > case RDMA_CM_EVENT_UNREACHABLE: /* FALLTHRU */ > diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h > index e512ba9..d0c5c2c 100644 > --- a/drivers/infiniband/ulp/isert/ib_isert.h > +++ b/drivers/infiniband/ulp/isert/ib_isert.h > @@ -159,6 +159,8 @@ struct isert_conn { > struct work_struct release_work; > bool logout_posted; > bool snd_w_inv; > + wait_queue_head_t rem_wait; > + bool dev_removed; > }; > > #define ISERT_MAX_CQ 64 > -- > 2.8.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index a990c04..9adc38d 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -405,6 +405,7 @@ isert_init_conn(struct isert_conn *isert_conn) INIT_LIST_HEAD(&isert_conn->node); init_completion(&isert_conn->login_comp); init_completion(&isert_conn->login_req_comp); + init_waitqueue_head(&isert_conn->rem_wait); kref_init(&isert_conn->kref); mutex_init(&isert_conn->mutex); INIT_WORK(&isert_conn->release_work, isert_release_work); @@ -580,7 +581,8 @@ isert_connect_release(struct isert_conn *isert_conn) BUG_ON(!device); isert_free_rx_descriptors(isert_conn); - if (isert_conn->cm_id) + if (isert_conn->cm_id && + !isert_conn->dev_removed) rdma_destroy_id(isert_conn->cm_id); if (isert_conn->qp) { @@ -595,7 +597,10 @@ isert_connect_release(struct isert_conn *isert_conn) isert_device_put(device); - kfree(isert_conn); + if (isert_conn->dev_removed) + wake_up_interruptible(&isert_conn->rem_wait); + else + kfree(isert_conn); } static void @@ -755,6 +760,7 @@ static int isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) { struct isert_np *isert_np = cma_id->context; + struct isert_conn *isert_conn; int ret = 0; isert_info("%s (%d): status %d id %p np %p\n", @@ -778,6 +784,20 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) case RDMA_CM_EVENT_DEVICE_REMOVAL: /* FALLTHRU */ case RDMA_CM_EVENT_TIMEWAIT_EXIT: /* FALLTHRU */ ret = isert_disconnected_handler(cma_id, event->event); + + if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL) { + isert_conn = cma_id->qp->qp_context; + isert_conn->dev_removed = true; + wait_event_interruptible(isert_conn->rem_wait, + isert_conn->state == ISER_CONN_DOWN); + + kfree(isert_conn); + /* + * return non-zero from the callback to destroy + * the rdma cm id + */ + return 1; + } break; case RDMA_CM_EVENT_REJECTED: /* FALLTHRU */ case RDMA_CM_EVENT_UNREACHABLE: /* FALLTHRU */ diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h index e512ba9..d0c5c2c 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.h +++ b/drivers/infiniband/ulp/isert/ib_isert.h @@ -159,6 +159,8 @@ struct isert_conn { struct work_struct release_work; bool logout_posted; bool snd_w_inv; + wait_queue_head_t rem_wait; + bool dev_removed; }; #define ISERT_MAX_CQ 64
When the low level driver exercises the hot unplug they would call rdma_cm cma_remove_one which would fire DEVICE_REMOVAL event to all cma consumers. Now, if consumer doesn't make sure they destroy all IB objects created on that IB device instance prior to finalizing all processing of DEVICE_REMOVAL callback, rdma_cm will let the lld to de-register with IB core and destroy the IB device instance. And if the consumer calls (say) ib_dereg_mr(), it will crash since that dev object is NULL. In the current implementation, iser-target just initiates the cleanup and returns from DEVICE_REMOVAL callback. This deferred work creates a race between iser-target cleaning IB objects(say MR) and lld destroying IB device instance. This patch includes the following fixes -> make sure that consumer frees all IB objects associated with device instance -> return non-zero from the callback to destroy the rdma_cm id --- drivers/infiniband/ulp/isert/ib_isert.c | 24 ++++++++++++++++++++++-- drivers/infiniband/ulp/isert/ib_isert.h | 2 ++ 2 files changed, 24 insertions(+), 2 deletions(-)