Previous atomic increment decrement logic expects the atomic count
to be '0' after the final decrement. Replacing atomic count with
refcount does not allow that, as refcount_dec() considers count of 1
as underflow. Therefore fix the current refcount logic by decrementing
the refcount and test if it is '0' on the final deref in
c4iw_destroy_cq(). Use wait_for_completion() instead of wait_event().
Fixes: 7183451f846d (RDMA/cxgb4: Use refcount_t instead of atomic_t for reference counting")
Signed-off-by: Dakshaja Uppalapati <dakshaja@xxxxxxxxxxx>
Reviewed-by: Potnuri Bharat Teja <bharat@xxxxxxxxxxx>
---
changelog:
v0->v1: used wait for completion instead of wait_event.
---
drivers/infiniband/hw/cxgb4/cq.c | 12 +++++++++---
drivers/infiniband/hw/cxgb4/ev.c | 6 ++----
drivers/infiniband/hw/cxgb4/iw_cxgb4.h | 3 ++-
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/infiniband/hw/cxgb4/cq.c b/drivers/infiniband/hw/cxgb4/cq.c
index 6c8c910..53f52fc 100644
--- a/drivers/infiniband/hw/cxgb4/cq.c
+++ b/drivers/infiniband/hw/cxgb4/cq.c
@@ -967,6 +967,12 @@ int c4iw_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
return !err || err == -ENODATA ? npolled : err;
}
+void c4iw_cq_rem_ref(struct c4iw_cq *chp)
+{
+ if (refcount_dec_and_test(&chp->refcnt))
+ complete(&chp->cq_rel_comp);
+}
+
int c4iw_destroy_cq(struct ib_cq *ib_cq, struct ib_udata *udata)
{
struct c4iw_cq *chp;
@@ -976,8 +982,8 @@ int c4iw_destroy_cq(struct ib_cq *ib_cq, struct ib_udata *udata)
chp = to_c4iw_cq(ib_cq);
xa_erase_irq(&chp->rhp->cqs, chp->cq.cqid);
- refcount_dec(&chp->refcnt);
- wait_event(chp->wait, !refcount_read(&chp->refcnt));
+ c4iw_cq_rem_ref(chp);
+ wait_for_completion(&chp->cq_rel_comp);
ucontext = rdma_udata_to_drv_context(udata, struct c4iw_ucontext,
ibucontext);
@@ -1081,7 +1087,7 @@ int c4iw_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
spin_lock_init(&chp->lock);
spin_lock_init(&chp->comp_handler_lock);
refcount_set(&chp->refcnt, 1);
- init_waitqueue_head(&chp->wait);
+ init_completion(&chp->cq_rel_comp);
ret = xa_insert_irq(&rhp->cqs, chp->cq.cqid, chp, GFP_KERNEL);
if (ret)
goto err_destroy_cq;
diff --git a/drivers/infiniband/hw/cxgb4/ev.c b/drivers/infiniband/hw/cxgb4/ev.c
index 7798d090..34211a5 100644
--- a/drivers/infiniband/hw/cxgb4/ev.c
+++ b/drivers/infiniband/hw/cxgb4/ev.c
@@ -213,8 +213,7 @@ void c4iw_ev_dispatch(struct c4iw_dev *dev, struct t4_cqe *err_cqe)
break;
}
done:
- if (refcount_dec_and_test(&chp->refcnt))
- wake_up(&chp->wait);
+ c4iw_cq_rem_ref(chp);
c4iw_qp_rem_ref(&qhp->ibqp);
out:
return;
@@ -234,8 +233,7 @@ int c4iw_ev_handler(struct c4iw_dev *dev, u32 qid)
spin_lock_irqsave(&chp->comp_handler_lock, flag);
(*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context);
spin_unlock_irqrestore(&chp->comp_handler_lock, flag);
- if (refcount_dec_and_test(&chp->refcnt))
- wake_up(&chp->wait);
+ c4iw_cq_rem_ref(chp);
} else {
pr_debug("unknown cqid 0x%x\n", qid);
xa_unlock_irqrestore(&dev->cqs, flag);
diff --git a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
index 3883af3..ac5f581 100644
--- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
+++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
@@ -428,7 +428,7 @@ struct c4iw_cq {
spinlock_t lock;
spinlock_t comp_handler_lock;
refcount_t refcnt;
- wait_queue_head_t wait;
+ struct completion cq_rel_comp;
struct c4iw_wr_wait *wr_waitp;
};
@@ -979,6 +979,7 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start,
struct ib_mr *c4iw_get_dma_mr(struct ib_pd *pd, int acc);
int c4iw_dereg_mr(struct ib_mr *ib_mr, struct ib_udata *udata);
int c4iw_destroy_cq(struct ib_cq *ib_cq, struct ib_udata *udata);
+void c4iw_cq_rem_ref(struct c4iw_cq *chp);
int c4iw_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
struct ib_udata *udata);
int c4iw_arm_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags);
--
1.8.3.1
