ath10k: prevent CE from looping indefinitely

The double while() could end up running forever.
Inner while() would complete very fast. However
the completion processing could take enough time
for more completions to flow in. In that case the
outer while() would not terminate and run again,
and again. This could happen especially on a slow
host system.

This could lead to a system freeze during heavy
traffic. Note: this doesn't solve all known
starvation issues yet.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

1 files changed, 10 insertions, 47 deletions

diff --git a/drivers/net/wireless/ath/ath10k/ce.c b/drivers/net/wireless/ath/ath10k/ce.c
index afe5df404ce6..924b29ec7a74 100644
--- a/drivers/net/wireless/ath/ath10k/ce.c
+++ b/drivers/net/wireless/ath/ath10k/ce.c
@@ -742,11 +742,6 @@ void ath10k_ce_per_engine_service(struct ath10k *ar, unsigned int ce_id)
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	struct ath10k_ce_pipe *ce_state = &ar_pci->ce_states[ce_id];
 	u32 ctrl_addr = ce_state->ctrl_addr;
-	void *transfer_context;
-	u32 buf;
-	unsigned int nbytes;
-	unsigned int id;
-	unsigned int flags;
 	int ret;
 
 	ret = ath10k_pci_wake(ar);
@@ -759,38 +754,15 @@ void ath10k_ce_per_engine_service(struct ath10k *ar, unsigned int ce_id)
 	ath10k_ce_engine_int_status_clear(ar, ctrl_addr,
 					  HOST_IS_COPY_COMPLETE_MASK);
 
-	if (ce_state->recv_cb) {
-		/*
-		 * Pop completed recv buffers and call the registered
-		 * recv callback for each
-		 */
-		while (ath10k_ce_completed_recv_next_nolock(ce_state,
-							    &transfer_context,
-							    &buf, &nbytes,
-							    &id, &flags) == 0) {
-			spin_unlock_bh(&ar_pci->ce_lock);
-			ce_state->recv_cb(ce_state, transfer_context, buf,
-					  nbytes, id, flags);
-			spin_lock_bh(&ar_pci->ce_lock);
-		}
-	}
+	spin_unlock_bh(&ar_pci->ce_lock);
 
-	if (ce_state->send_cb) {
-		/*
-		 * Pop completed send buffers and call the registered
-		 * send callback for each
-		 */
-		while (ath10k_ce_completed_send_next_nolock(ce_state,
-							    &transfer_context,
-							    &buf,
-							    &nbytes,
-							    &id) == 0) {
-			spin_unlock_bh(&ar_pci->ce_lock);
-			ce_state->send_cb(ce_state, transfer_context,
-					  buf, nbytes, id);
-			spin_lock_bh(&ar_pci->ce_lock);
-		}
-	}
+	if (ce_state->recv_cb)
+		ce_state->recv_cb(ce_state);
+
+	if (ce_state->send_cb)
+		ce_state->send_cb(ce_state);
+
+	spin_lock_bh(&ar_pci->ce_lock);
 
 	/*
 	 * Misc CE interrupts are not being handled, but still need
@@ -881,11 +853,7 @@ void ath10k_ce_disable_interrupts(struct ath10k *ar)
 }
 
 void ath10k_ce_send_cb_register(struct ath10k_ce_pipe *ce_state,
-				void (*send_cb)(struct ath10k_ce_pipe *ce_state,
-						void *transfer_context,
-						u32 buffer,
-						unsigned int nbytes,
-						unsigned int transfer_id),
+				void (*send_cb)(struct ath10k_ce_pipe *),
 				int disable_interrupts)
 {
 	struct ath10k *ar = ce_state->ar;
@@ -898,12 +866,7 @@ void ath10k_ce_send_cb_register(struct ath10k_ce_pipe *ce_state,
 }
 
 void ath10k_ce_recv_cb_register(struct ath10k_ce_pipe *ce_state,
-				void (*recv_cb)(struct ath10k_ce_pipe *ce_state,
-						void *transfer_context,
-						u32 buffer,
-						unsigned int nbytes,
-						unsigned int transfer_id,
-						unsigned int flags))
+				void (*recv_cb)(struct ath10k_ce_pipe *))
 {
 	struct ath10k *ar = ce_state->ar;
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);