From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH v2 1/1] IB/iSER-Target: Release connection resources properly when receiving RDMA_CM_EVENT_DEVICE_REMOVAL Date: Tue, 2 Aug 2016 12:15:47 +0300 Message-ID: References: <20160802084635.14414-1-rajur@chelsio.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160802084635.14414-1-rajur-ut6Up61K2wZBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Raju Rangoju , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org, target-devel , "Nicholas A. Bellinger" List-Id: linux-rdma@vger.kernel.org > 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 > > Signed-off-by: Raju Rangoju > --- > Changes since v1: > - Added S.O.B note Hi Raju, I forgot to mention it, but iser-target patches usually go via the scsi target tree. CCing target-devel and Nic. And, you forgot my ack tag: Acked-by: Sagi Grimberg > > drivers/infiniband/ulp/isert/ib_isert.c | 23 ++++++++++++++++++++--- > drivers/infiniband/ulp/isert/ib_isert.h | 2 ++ > 2 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c > index a990c04..3dfd903 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", > @@ -775,10 +781,21 @@ isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event) > break; > case RDMA_CM_EVENT_ADDR_CHANGE: /* FALLTHRU */ > case RDMA_CM_EVENT_DISCONNECTED: /* FALLTHRU */ > - case RDMA_CM_EVENT_DEVICE_REMOVAL: /* FALLTHRU */ > case RDMA_CM_EVENT_TIMEWAIT_EXIT: /* FALLTHRU */ > ret = isert_disconnected_handler(cma_id, event->event); > break; > + case RDMA_CM_EVENT_DEVICE_REMOVAL: > + isert_conn = cma_id->qp->qp_context; > + isert_conn->dev_removed = true; > + isert_disconnected_handler(cma_id, event->event); > + 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; > case RDMA_CM_EVENT_REJECTED: /* FALLTHRU */ > case RDMA_CM_EVENT_UNREACHABLE: /* FALLTHRU */ > case RDMA_CM_EVENT_CONNECT_ERROR: > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html