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IB/cm: Fix sleeping in atomic when RoCE is used

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A couple of places in the CM do

    spin_lock_irq(&cm_id_priv->lock);
    ...
    if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg))

However when the underlying transport is RoCE, this leads to a sleeping function
being called with the lock held - the callchain is

    cm_alloc_response_msg() ->
      ib_create_ah_from_wc() ->
        ib_init_ah_from_wc() ->
          rdma_addr_find_l2_eth_by_grh() ->
            rdma_resolve_ip()

and rdma_resolve_ip() starts out by doing

    req = kzalloc(sizeof *req, GFP_KERNEL);

not to mention rdma_addr_find_l2_eth_by_grh() doing

    wait_for_completion(&ctx.comp);

to wait for the task that rdma_resolve_ip() queues up.

Fix this by moving the AH creation out of the lock.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Roland Dreier 2017-08-29 10:34:43 -07:00 committed by Doug Ledford
parent f43dbebfa3
commit c761611811
1 changed files with 44 additions and 19 deletions
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63
drivers/infiniband/core/cm.c
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@ -373,11 +373,19 @@ static int cm_alloc_msg(struct cm_id_private *cm_id_priv,
return ret;
}
static int cm_alloc_response_msg(struct cm_port *port,
struct ib_mad_recv_wc *mad_recv_wc,
struct ib_mad_send_buf **msg)
static struct ib_mad_send_buf *cm_alloc_response_msg_no_ah(struct cm_port *port,
struct ib_mad_recv_wc *mad_recv_wc)
{
return ib_create_send_mad(port->mad_agent, 1, mad_recv_wc->wc->pkey_index,
0, IB_MGMT_MAD_HDR, IB_MGMT_MAD_DATA,
GFP_ATOMIC,
IB_MGMT_BASE_VERSION);
}
static int cm_create_response_msg_ah(struct cm_port *port,
struct ib_mad_recv_wc *mad_recv_wc,
struct ib_mad_send_buf *msg)
{
struct ib_mad_send_buf *m;
struct ib_ah *ah;
ah = ib_create_ah_from_wc(port->mad_agent->qp->pd, mad_recv_wc->wc,
@ -385,27 +393,40 @@ static int cm_alloc_response_msg(struct cm_port *port,
if (IS_ERR(ah))
return PTR_ERR(ah);
m = ib_create_send_mad(port->mad_agent, 1, mad_recv_wc->wc->pkey_index,
0, IB_MGMT_MAD_HDR, IB_MGMT_MAD_DATA,
GFP_ATOMIC,
IB_MGMT_BASE_VERSION);
if (IS_ERR(m)) {
rdma_destroy_ah(ah);
return PTR_ERR(m);
}
m->ah = ah;
*msg = m;
msg->ah = ah;
return 0;
}
static void cm_free_msg(struct ib_mad_send_buf *msg)
{
rdma_destroy_ah(msg->ah);
if (msg->ah)
rdma_destroy_ah(msg->ah);
if (msg->context[0])
cm_deref_id(msg->context[0]);
ib_free_send_mad(msg);
}
static int cm_alloc_response_msg(struct cm_port *port,
struct ib_mad_recv_wc *mad_recv_wc,
struct ib_mad_send_buf **msg)
{
struct ib_mad_send_buf *m;
int ret;
m = cm_alloc_response_msg_no_ah(port, mad_recv_wc);
if (IS_ERR(m))
return PTR_ERR(m);
ret = cm_create_response_msg_ah(port, mad_recv_wc, m);
if (ret) {
cm_free_msg(m);
return ret;
}
*msg = m;
return 0;
}
static void * cm_copy_private_data(const void *private_data,
u8 private_data_len)
{
@ -2497,7 +2518,8 @@ static int cm_dreq_handler(struct cm_work *work)
case IB_CM_TIMEWAIT:
atomic_long_inc(&work->port->counter_group[CM_RECV_DUPLICATES].
counter[CM_DREQ_COUNTER]);
if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg))
msg = cm_alloc_response_msg_no_ah(work->port, work->mad_recv_wc);
if (IS_ERR(msg))
goto unlock;
cm_format_drep((struct cm_drep_msg *) msg->mad, cm_id_priv,
@ -2505,7 +2527,8 @@ static int cm_dreq_handler(struct cm_work *work)
cm_id_priv->private_data_len);
spin_unlock_irq(&cm_id_priv->lock);
if (ib_post_send_mad(msg, NULL))
if (cm_create_response_msg_ah(work->port, work->mad_recv_wc, msg) ||
ib_post_send_mad(msg, NULL))
cm_free_msg(msg);
goto deref;
case IB_CM_DREQ_RCVD:
@ -3083,7 +3106,8 @@ static int cm_lap_handler(struct cm_work *work)
case IB_CM_MRA_LAP_SENT:
atomic_long_inc(&work->port->counter_group[CM_RECV_DUPLICATES].
counter[CM_LAP_COUNTER]);
if (cm_alloc_response_msg(work->port, work->mad_recv_wc, &msg))
msg = cm_alloc_response_msg_no_ah(work->port, work->mad_recv_wc);
if (IS_ERR(msg))
goto unlock;
cm_format_mra((struct cm_mra_msg *) msg->mad, cm_id_priv,
@ -3093,7 +3117,8 @@ static int cm_lap_handler(struct cm_work *work)
cm_id_priv->private_data_len);
spin_unlock_irq(&cm_id_priv->lock);
if (ib_post_send_mad(msg, NULL))
if (cm_create_response_msg_ah(work->port, work->mad_recv_wc, msg) ||
ib_post_send_mad(msg, NULL))
cm_free_msg(msg);
goto deref;
case IB_CM_LAP_RCVD: