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IB/isert: Properly release resources on DEVICE_REMOVAL

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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 <rajur@chelsio.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Raju Rangoju 2016-08-29 17:15:49 +05:30 committed by Doug Ledford
parent 6aaa382f12
commit 63b268d232
2 changed files with 22 additions and 3 deletions
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21
drivers/infiniband/ulp/isert/ib_isert.c
View File

@ -403,6 +403,7 @@ 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);
@ -578,7 +579,8 @@ 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) {
@ -593,6 +595,9 @@ isert_connect_release(struct isert_conn *isert_conn)
isert_device_put(device);
if (isert_conn->dev_removed)
wake_up_interruptible(&isert_conn->rem_wait);
else
kfree(isert_conn);
}
@ -753,6 +758,7 @@ 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",
@ -773,10 +779,21 @@ 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:

2
drivers/infiniband/ulp/isert/ib_isert.h
View File

@ -158,6 +158,8 @@ 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