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authorSteve Wise <swise@opengridcomputing.com>2016-07-29 18:00:54 (GMT)
committerDoug Ledford <dledford@redhat.com>2016-08-02 17:15:17 (GMT)
commitad61a4c7a9b7ae7e10ca93b0d2b357e02c208e75 (patch)
tree4de771678e532015a7793120a386d2e5bab372c8 /drivers/infiniband/hw/cxgb4
parent1b1a889dbb9f007bc8fc916f172701cd8b1f7098 (diff)
downloadlinux-ad61a4c7a9b7ae7e10ca93b0d2b357e02c208e75.tar.xz
iw_cxgb4: don't block in destroy_qp awaiting the last deref
Blocking in c4iw_destroy_qp() causes a deadlock when apps destroy a qp or disconnect a cm_id from their cm event handler function. There is no need to block here anyway, so just replace the refcnt atomic with a kref object and free the memory on the last put. Signed-off-by: Steve Wise <swise@opengridcomputing.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband/hw/cxgb4')
-rw-r--r--drivers/infiniband/hw/cxgb4/iw_cxgb4.h2
-rw-r--r--drivers/infiniband/hw/cxgb4/qp.c21
2 files changed, 15 insertions, 8 deletions
diff --git a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
index c5f5881..aa47e0a 100644
--- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
+++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
@@ -475,7 +475,7 @@ struct c4iw_qp {
struct t4_wq wq;
spinlock_t lock;
struct mutex mutex;
- atomic_t refcnt;
+ struct kref kref;
wait_queue_head_t wait;
struct timer_list timer;
int sq_sig_all;
diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
index 28a76a5..edb1172 100644
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -683,17 +683,25 @@ static int build_inv_stag(union t4_wr *wqe, struct ib_send_wr *wr,
return 0;
}
+void _free_qp(struct kref *kref)
+{
+ struct c4iw_qp *qhp;
+
+ qhp = container_of(kref, struct c4iw_qp, kref);
+ PDBG("%s qhp %p\n", __func__, qhp);
+ kfree(qhp);
+}
+
void c4iw_qp_add_ref(struct ib_qp *qp)
{
PDBG("%s ib_qp %p\n", __func__, qp);
- atomic_inc(&(to_c4iw_qp(qp)->refcnt));
+ kref_get(&to_c4iw_qp(qp)->kref);
}
void c4iw_qp_rem_ref(struct ib_qp *qp)
{
PDBG("%s ib_qp %p\n", __func__, qp);
- if (atomic_dec_and_test(&(to_c4iw_qp(qp)->refcnt)))
- wake_up(&(to_c4iw_qp(qp)->wait));
+ kref_put(&to_c4iw_qp(qp)->kref, _free_qp);
}
static void add_to_fc_list(struct list_head *head, struct list_head *entry)
@@ -1594,8 +1602,6 @@ int c4iw_destroy_qp(struct ib_qp *ib_qp)
wait_event(qhp->wait, !qhp->ep);
remove_handle(rhp, &rhp->qpidr, qhp->wq.sq.qid);
- atomic_dec(&qhp->refcnt);
- wait_event(qhp->wait, !atomic_read(&qhp->refcnt));
spin_lock_irq(&rhp->lock);
if (!list_empty(&qhp->db_fc_entry))
@@ -1608,8 +1614,9 @@ int c4iw_destroy_qp(struct ib_qp *ib_qp)
destroy_qp(&rhp->rdev, &qhp->wq,
ucontext ? &ucontext->uctx : &rhp->rdev.uctx);
+ c4iw_qp_rem_ref(ib_qp);
+
PDBG("%s ib_qp %p qpid 0x%0x\n", __func__, ib_qp, qhp->wq.sq.qid);
- kfree(qhp);
return 0;
}
@@ -1706,7 +1713,7 @@ struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
init_completion(&qhp->rq_drained);
mutex_init(&qhp->mutex);
init_waitqueue_head(&qhp->wait);
- atomic_set(&qhp->refcnt, 1);
+ kref_init(&qhp->kref);
ret = insert_handle(rhp, &rhp->qpidr, qhp, qhp->wq.sq.qid);
if (ret)