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IB/iser: Fix DEVICE REMOVAL handling in the absence of iscsi daemon

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iscsi daemon is in user-space, thus we can't rely on it to be invoked
at connection teardown (if not running or does not receive CPU time).

This patch addresses the issue by re-structuring iSER connection
teardown logic and CM events handling.

The CM events will dictate the RDMA resources destruction (ib_conn)
and iser_conn is kept around as long as iscsi_conn is left around
allowing iscsi/iser callbacks to continue after RDMA transport was
destroyed.

This patch introduces a separation in logic when handling CM events:

- DISCONNECTED_HANDLER, ADDR_CHANGED
  This events indicate the start of teardown process.
  Actions:
  1. Terminate the connection: rdma_disconnect (send DREQ/DREP)
  2. Notify iSCSI of connection failure
  3. Change state to TERMINATING
  4. Poll for all flush errors to be consumed

- TIMEWAIT_EXIT, DEVICE_REMOVAL
  These events indicate the final stage of termination process and
  we can free RDMA related resources.
  Actions:
  1. Call disconnected handler (we are not guaranteed that DISCONNECTED
     event was invoked in the past)
  2. Cleanup RDMA related resources
  3. For DEVICE_REMOVAL return non-zero rc from cma_handler to
     implicitly destroy the cm_id (Can't rely on user-space, make sure
     we have forward progress)

We replace flush_completion (indicate all flushes were consumed) with
ib_completion (rdma resources were cleaned up).

The iser_conn_release_work will wait for teardown completions:

- conn_stop was completed (tasks were cleaned-up) - stop_completion
- RDMA resources were destroyed - ib_completion

And then will continue to free iser connection representation (iser_conn).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Sagi Grimberg 2014-10-01 14:02:01 +03:00 committed by Roland Dreier
parent 96f15198c1
commit c47a3c9ed5
2 changed files with 111 additions and 64 deletions
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6
drivers/infiniband/ulp/iser/iscsi_iser.h
View File

@ -370,9 +370,9 @@ struct iser_conn {
unsigned min_posted_rx; /* qp_max_recv_dtos >> 2 */
char name[ISER_OBJECT_NAME_SIZE];
struct work_struct release_work;
struct completion stop_completion;
struct mutex state_mutex;
struct completion flush_completion;
struct completion stop_completion;
struct completion ib_completion;
struct completion up_completion;
struct list_head conn_list; /* entry in ig conn list */
@ -442,7 +442,7 @@ void iser_conn_init(struct iser_conn *iser_conn);
void iser_conn_release(struct iser_conn *iser_conn);
void iser_conn_terminate(struct iser_conn *iser_conn);
int iser_conn_terminate(struct iser_conn *iser_conn);
void iser_release_work(struct work_struct *work);

169
drivers/infiniband/ulp/iser/iser_verbs.c
View File

@ -44,6 +44,7 @@
static void iser_cq_tasklet_fn(unsigned long data);
static void iser_cq_callback(struct ib_cq *cq, void *cq_context);
static int iser_drain_tx_cq(struct iser_device *device, int cq_index);
static void iser_cq_event_callback(struct ib_event *cause, void *context)
{
@ -573,11 +574,10 @@ void iser_release_work(struct work_struct *work)
rc = wait_for_completion_timeout(&iser_conn->stop_completion, 30 * HZ);
WARN_ON(rc == 0);
/* wait for the qp`s post send and post receive buffers to empty */
rc = wait_for_completion_timeout(&iser_conn->flush_completion, 30 * HZ);
WARN_ON(rc == 0);
iser_conn->state = ISER_CONN_DOWN;
rc = wait_for_completion_timeout(&iser_conn->ib_completion, 30 * HZ);
if (rc == 0)
iser_warn("conn %p, IB cleanup didn't complete in 30 "
"seconds, continue with release\n", iser_conn);
mutex_lock(&iser_conn->state_mutex);
iser_conn->state = ISER_CONN_DOWN;
@ -589,12 +589,16 @@ void iser_release_work(struct work_struct *work)
/**
* iser_free_ib_conn_res - release IB related resources
* @iser_conn: iser connection struct
* @destroy_device: indicator if we need to try to release
* the iser device (only iscsi shutdown and DEVICE_REMOVAL
* will use this.
*
* This routine is called with the iser state mutex held
* so the cm_id removal is out of here. It is Safe to
* be invoked multiple times.
*/
static void iser_free_ib_conn_res(struct iser_conn *iser_conn)
static void iser_free_ib_conn_res(struct iser_conn *iser_conn,
bool destroy_device)
{
struct ib_conn *ib_conn = &iser_conn->ib_conn;
struct iser_device *device = ib_conn->device;
@ -610,7 +614,7 @@ static void iser_free_ib_conn_res(struct iser_conn *iser_conn)
ib_conn->qp = NULL;
}
if (device != NULL) {
if (destroy_device && device != NULL) {
iser_device_try_release(device);
ib_conn->device = NULL;
}
@ -629,7 +633,11 @@ void iser_conn_release(struct iser_conn *iser_conn)
mutex_lock(&iser_conn->state_mutex);
BUG_ON(iser_conn->state != ISER_CONN_DOWN);
iser_free_ib_conn_res(iser_conn);
/*
* In case we never got to bind stage, we still need to
* release IB resources (which is safe to call more than once).
*/
iser_free_ib_conn_res(iser_conn, true);
mutex_unlock(&iser_conn->state_mutex);
if (ib_conn->cma_id != NULL) {
@ -641,23 +649,68 @@ void iser_conn_release(struct iser_conn *iser_conn)
}
/**
* triggers start of the disconnect procedures and wait for them to be done
* iser_poll_for_flush_errors - Don't settle for less than all.
* @struct ib_conn: IB context of the connection
*
* This routine is called when the QP is in error state
* It polls the send CQ until all flush errors are consumed and
* returns when all flush errors were processed.
*/
void iser_conn_terminate(struct iser_conn *iser_conn)
static void iser_poll_for_flush_errors(struct ib_conn *ib_conn)
{
struct iser_device *device = ib_conn->device;
int count = 0;
while (ib_conn->post_recv_buf_count > 0 ||
atomic_read(&ib_conn->post_send_buf_count) > 0) {
msleep(100);
if (atomic_read(&ib_conn->post_send_buf_count) > 0)
iser_drain_tx_cq(device, ib_conn->cq_index);
count++;
/* Don't flood with prints */
if (count % 30 == 0)
iser_dbg("post_recv %d post_send %d",
ib_conn->post_recv_buf_count,
atomic_read(&ib_conn->post_send_buf_count));
}
}
/**
* triggers start of the disconnect procedures and wait for them to be done
* Called with state mutex held
*/
int iser_conn_terminate(struct iser_conn *iser_conn)
{
struct ib_conn *ib_conn = &iser_conn->ib_conn;
int err = 0;
/* change the ib conn state only if the conn is UP, however always call
* rdma_disconnect since this is the only way to cause the CMA to change
* the QP state to ERROR
*/
/* terminate the iser conn only if the conn state is UP */
if (!iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
ISER_CONN_TERMINATING))
return 0;
iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
err = rdma_disconnect(ib_conn->cma_id);
if (err)
iser_err("Failed to disconnect, conn: 0x%p err %d\n",
iser_conn, err);
iser_info("iser_conn %p state %d\n", iser_conn, iser_conn->state);
/* suspend queuing of new iscsi commands */
if (iser_conn->iscsi_conn)
iscsi_suspend_queue(iser_conn->iscsi_conn);
/*
* In case we didn't already clean up the cma_id (peer initiated
* a disconnection), we need to Cause the CMA to change the QP
* state to ERROR.
*/
if (ib_conn->cma_id) {
err = rdma_disconnect(ib_conn->cma_id);
if (err)
iser_err("Failed to disconnect, conn: 0x%p err %d\n",
iser_conn, err);
iser_poll_for_flush_errors(ib_conn);
}
return 1;
}
/**
@ -780,34 +833,36 @@ static void iser_connected_handler(struct rdma_cm_id *cma_id)
static void iser_disconnected_handler(struct rdma_cm_id *cma_id)
{
struct iser_conn *iser_conn;
struct ib_conn *ib_conn = &iser_conn->ib_conn;
struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
iser_conn = (struct iser_conn *)cma_id->context;
/* getting here when the state is UP means that the conn is being *
* terminated asynchronously from the iSCSI layer's perspective. */
if (iser_conn_state_comp_exch(iser_conn, ISER_CONN_UP,
ISER_CONN_TERMINATING)){
if (iser_conn_terminate(iser_conn)) {
if (iser_conn->iscsi_conn)
iscsi_conn_failure(iser_conn->iscsi_conn, ISCSI_ERR_CONN_FAILED);
iscsi_conn_failure(iser_conn->iscsi_conn,
ISCSI_ERR_CONN_FAILED);
else
iser_err("iscsi_iser connection isn't bound\n");
}
/* Complete the termination process if no posts are pending. This code
* block also exists in iser_handle_comp_error(), but it is needed here
* for cases of no flushes at all, e.g. discovery over rdma.
*/
if (ib_conn->post_recv_buf_count == 0 &&
(atomic_read(&ib_conn->post_send_buf_count) == 0)) {
complete(&iser_conn->flush_completion);
}
}
static void iser_cleanup_handler(struct rdma_cm_id *cma_id,
bool destroy_device)
{
struct iser_conn *iser_conn = (struct iser_conn *)cma_id->context;
/*
* We are not guaranteed that we visited disconnected_handler
* by now, call it here to be safe that we handle CM drep
* and flush errors.
*/
iser_disconnected_handler(cma_id);
iser_free_ib_conn_res(iser_conn, destroy_device);
complete(&iser_conn->ib_completion);
};
static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
{
struct iser_conn *iser_conn;
int ret = 0;
iser_conn = (struct iser_conn *)cma_id->context;
iser_info("event %d status %d conn %p id %p\n",
@ -832,17 +887,29 @@ static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *eve
iser_connect_error(cma_id);
break;
case RDMA_CM_EVENT_DISCONNECTED:
case RDMA_CM_EVENT_DEVICE_REMOVAL:
case RDMA_CM_EVENT_ADDR_CHANGE:
case RDMA_CM_EVENT_TIMEWAIT_EXIT:
iser_disconnected_handler(cma_id);
break;
case RDMA_CM_EVENT_DEVICE_REMOVAL:
/*
* we *must* destroy the device as we cannot rely
* on iscsid to be around to initiate error handling.
* also implicitly destroy the cma_id.
*/
iser_cleanup_handler(cma_id, true);
iser_conn->ib_conn.cma_id = NULL;
ret = 1;
break;
case RDMA_CM_EVENT_TIMEWAIT_EXIT:
iser_cleanup_handler(cma_id, false);
break;
default:
iser_err("Unexpected RDMA CM event (%d)\n", event->event);
break;
}
mutex_unlock(&iser_conn->state_mutex);
return 0;
return ret;
}
void iser_conn_init(struct iser_conn *iser_conn)
@ -851,7 +918,7 @@ void iser_conn_init(struct iser_conn *iser_conn)
iser_conn->ib_conn.post_recv_buf_count = 0;
atomic_set(&iser_conn->ib_conn.post_send_buf_count, 0);
init_completion(&iser_conn->stop_completion);
init_completion(&iser_conn->flush_completion);
init_completion(&iser_conn->ib_completion);
init_completion(&iser_conn->up_completion);
INIT_LIST_HEAD(&iser_conn->conn_list);
spin_lock_init(&iser_conn->ib_conn.lock);
@ -1100,28 +1167,8 @@ int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc)
static void iser_handle_comp_error(struct iser_tx_desc *desc,
struct ib_conn *ib_conn)
{
struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
ib_conn);
if (desc && desc->type == ISCSI_TX_DATAOUT)
kmem_cache_free(ig.desc_cache, desc);
if (ib_conn->post_recv_buf_count == 0 &&
atomic_read(&ib_conn->post_send_buf_count) == 0) {
/**
* getting here when the state is UP means that the conn is
* being terminated asynchronously from the iSCSI layer's
* perspective. It is safe to peek at the connection state
* since iscsi_conn_failure is allowed to be called twice.
**/
if (iser_conn->state == ISER_CONN_UP)
iscsi_conn_failure(iser_conn->iscsi_conn,
ISCSI_ERR_CONN_FAILED);
/* no more non completed posts to the QP, complete the
* termination process w.o worrying on disconnect event */
complete(&iser_conn->flush_completion);
}
}
static int iser_drain_tx_cq(struct iser_device *device, int cq_index)