From: Amir Vadai <amirv@mellanox.co.il>
Date: Mon, 7 Dec 2009 13:31:58 +0000 (+0200)
Subject: sdp: fix lockup on mthca cards
X-Git-Tag: v4.1.12-92~264^2~5^2~230
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=26daa321e6ae93215e36c86e6794936069807d37;p=users%2Fjedix%2Flinux-maple.git

sdp: fix lockup on mthca cards

- rx_irq called sdp_sock_queue_rcv_skb() who calls
  sk->sk_data_ready() == sock_def_readable

- sock_def_readable() can't be called from interrupt context
  because it takes read_lock (the writer to the lock uses
  write_lock_bh)

- moved rx processing to tasklet

sock_def_readable was trying to take read_lock

Signed-off-by: Amir Vadai <amirv@mellanox.co.il>
---

diff --git a/drivers/infiniband/ulp/sdp/sdp.h b/drivers/infiniband/ulp/sdp/sdp.h
index 3bbabd21a2c1..09bea8711352 100644
--- a/drivers/infiniband/ulp/sdp/sdp.h
+++ b/drivers/infiniband/ulp/sdp/sdp.h
@@ -277,6 +277,8 @@ struct sdp_rx_ring {
 
 	int		 destroyed;
 	rwlock_t 	 destroyed_lock;
+
+	struct tasklet_struct 	tasklet;
 };
 
 struct sdp_device {
@@ -414,18 +416,16 @@ static inline void tx_sa_reset(struct tx_srcavail_state *tx_sa)
 			sizeof(*tx_sa) - offsetof(typeof(*tx_sa), busy));
 }
 
-static inline void rx_ring_unlock(struct sdp_rx_ring *rx_ring,
-		unsigned long *flags)
+static inline void rx_ring_unlock(struct sdp_rx_ring *rx_ring)
 {
-	read_unlock_irqrestore(&rx_ring->destroyed_lock, *flags);
+	read_unlock_bh(&rx_ring->destroyed_lock);
 }
 
-static inline int rx_ring_trylock(struct sdp_rx_ring *rx_ring,
-		unsigned long *flags)
+static inline int rx_ring_trylock(struct sdp_rx_ring *rx_ring)
 {
-	read_lock_irqsave(&rx_ring->destroyed_lock, *flags);
+	read_lock_bh(&rx_ring->destroyed_lock);
 	if (rx_ring->destroyed) {
-		rx_ring_unlock(rx_ring, flags);
+		rx_ring_unlock(rx_ring);
 		return 0;
 	}
 	return 1;
@@ -433,11 +433,9 @@ static inline int rx_ring_trylock(struct sdp_rx_ring *rx_ring,
 
 static inline void rx_ring_destroy_lock(struct sdp_rx_ring *rx_ring)
 {
-	unsigned long flags;
-
-	write_lock_irqsave(&rx_ring->destroyed_lock, flags);
+	write_lock_bh(&rx_ring->destroyed_lock);
 	rx_ring->destroyed = 1;
-	write_unlock_irqrestore(&rx_ring->destroyed_lock, flags);
+	write_unlock_bh(&rx_ring->destroyed_lock);
 }
 
 static inline struct sdp_sock *sdp_sk(const struct sock *sk)
diff --git a/drivers/infiniband/ulp/sdp/sdp_rx.c b/drivers/infiniband/ulp/sdp/sdp_rx.c
index 3e65b2608cb6..e6dd79f75b0b 100644
--- a/drivers/infiniband/ulp/sdp/sdp_rx.c
+++ b/drivers/infiniband/ulp/sdp/sdp_rx.c
@@ -798,9 +798,6 @@ static void sdp_rx_irq(struct ib_cq *cq, void *cq_context)
 {
 	struct sock *sk = cq_context;
 	struct sdp_sock *ssk = sdp_sk(sk);
-	unsigned long flags;
-	int wc_processed = 0;
-	int credits_before;
 
 	if (cq != ssk->rx_ring.cq) {
 		sdp_dbg(sk, "cq = %p, ssk->cq = %p\n", cq, ssk->rx_ring.cq);
@@ -811,7 +808,17 @@ static void sdp_rx_irq(struct ib_cq *cq, void *cq_context)
 
 	sdp_prf(sk, NULL, "rx irq");
 
-	if (!rx_ring_trylock(&ssk->rx_ring, &flags)) {
+	tasklet_hi_schedule(&ssk->rx_ring.tasklet);
+}
+
+static void sdp_process_rx(unsigned long data)
+{
+	struct sdp_sock *ssk = (struct sdp_sock *)data;
+	struct sock *sk = &ssk->isk.sk;
+	int wc_processed = 0;
+	int credits_before;
+
+	if (!rx_ring_trylock(&ssk->rx_ring)) {
 		sdp_dbg(&ssk->isk.sk, "ring destroyed. not polling it\n");
 		return;
 	}
@@ -840,7 +847,7 @@ static void sdp_rx_irq(struct ib_cq *cq, void *cq_context)
 	}
 	sdp_arm_rx_cq(sk);
 
-	rx_ring_unlock(&ssk->rx_ring, &flags);
+	rx_ring_unlock(&ssk->rx_ring);
 }
 
 static void sdp_rx_ring_purge(struct sdp_sock *ssk)
@@ -898,6 +905,8 @@ int sdp_rx_ring_create(struct sdp_sock *ssk, struct ib_device *device)
 	sdp_sk(&ssk->isk.sk)->rx_ring.cq = rx_cq;
 
 	INIT_WORK(&ssk->rx_comp_work, sdp_rx_comp_work);
+	tasklet_init(&ssk->rx_ring.tasklet, sdp_process_rx,
+			(unsigned long) ssk);
 
 	sdp_arm_rx_cq(&ssk->isk.sk);