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RDMA/iwcm: iw_cm_id destruction race fixes

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iwcm iw_cm_id destruction race condition fixes:

- iwcm_deref_id() always wakes up if there's another reference.
- clean up race condition in cm_work_handler().
- create static void free_cm_id() which deallocs the work entries and then
  kfrees the cm_id memory.  This reduces code replication.
- rem_ref() if this is the last reference -and- the IWCM owns freeing the
  cm_id, then free it.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Steve Wise 2007-02-15 08:09:36 -06:00 committed by Roland Dreier
parent 6bbcea0d42
commit ebb90986e1
1 changed files with 25 additions and 22 deletions
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47
drivers/infiniband/core/iwcm.c
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@ -146,6 +146,12 @@ static int copy_private_data(struct iw_cm_event *event)
return 0;
}
static void free_cm_id(struct iwcm_id_private *cm_id_priv)
{
dealloc_work_entries(cm_id_priv);
kfree(cm_id_priv);
}
/*
* Release a reference on cm_id. If the last reference is being
* released, enable the waiting thread (in iw_destroy_cm_id) to
@ -153,21 +159,14 @@ static int copy_private_data(struct iw_cm_event *event)
*/
static int iwcm_deref_id(struct iwcm_id_private *cm_id_priv)
{
int ret = 0;
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
if (atomic_dec_and_test(&cm_id_priv->refcount)) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
if (waitqueue_active(&cm_id_priv->destroy_comp.wait)) {
BUG_ON(cm_id_priv->state != IW_CM_STATE_DESTROYING);
BUG_ON(test_bit(IWCM_F_CALLBACK_DESTROY,
&cm_id_priv->flags));
ret = 1;
}
complete(&cm_id_priv->destroy_comp);
return 1;
}
return ret;
return 0;
}
static void add_ref(struct iw_cm_id *cm_id)
@ -181,7 +180,11 @@ static void rem_ref(struct iw_cm_id *cm_id)
{
struct iwcm_id_private *cm_id_priv;
cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
iwcm_deref_id(cm_id_priv);
if (iwcm_deref_id(cm_id_priv) &&
test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}
}
static int cm_event_handler(struct iw_cm_id *cm_id, struct iw_cm_event *event);
@ -355,7 +358,9 @@ static void destroy_cm_id(struct iw_cm_id *cm_id)
case IW_CM_STATE_CONN_RECV:
/*
* App called destroy before/without calling accept after
* receiving connection request event notification.
* receiving connection request event notification or
* returned non zero from the event callback function.
* In either case, must tell the provider to reject.
*/
cm_id_priv->state = IW_CM_STATE_DESTROYING;
break;
@ -391,9 +396,7 @@ void iw_destroy_cm_id(struct iw_cm_id *cm_id)
wait_for_completion(&cm_id_priv->destroy_comp);
dealloc_work_entries(cm_id_priv);
kfree(cm_id_priv);
free_cm_id(cm_id_priv);
}
EXPORT_SYMBOL(iw_destroy_cm_id);
@ -647,10 +650,11 @@ static void cm_conn_req_handler(struct iwcm_id_private *listen_id_priv,
/* Call the client CM handler */
ret = cm_id->cm_handler(cm_id, iw_event);
if (ret) {
iw_cm_reject(cm_id, NULL, 0);
set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
destroy_cm_id(cm_id);
if (atomic_read(&cm_id_priv->refcount)==0)
kfree(cm_id);
free_cm_id(cm_id_priv);
}
out:
@ -854,13 +858,12 @@ static void cm_work_handler(struct work_struct *_work)
destroy_cm_id(&cm_id_priv->id);
}
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
if (iwcm_deref_id(cm_id_priv))
return;
if (atomic_read(&cm_id_priv->refcount)==0 &&
test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags)) {
dealloc_work_entries(cm_id_priv);
kfree(cm_id_priv);
if (iwcm_deref_id(cm_id_priv)) {
if (test_bit(IWCM_F_CALLBACK_DESTROY,
&cm_id_priv->flags)) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}
return;
}
spin_lock_irqsave(&cm_id_priv->lock, flags);