1 files changed, 51 insertions, 86 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index c3a6072134f5..2559206d8704 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -531,20 +531,8 @@ struct bnx2x_fastpath {
 	struct napi_struct	napi;
 
 #ifdef CONFIG_NET_RX_BUSY_POLL
-	unsigned int state;
-#define BNX2X_FP_STATE_IDLE		      0
-#define BNX2X_FP_STATE_NAPI		(1 << 0)    /* NAPI owns this FP */
-#define BNX2X_FP_STATE_POLL		(1 << 1)    /* poll owns this FP */
-#define BNX2X_FP_STATE_DISABLED		(1 << 2)
-#define BNX2X_FP_STATE_NAPI_YIELD	(1 << 3)    /* NAPI yielded this FP */
-#define BNX2X_FP_STATE_POLL_YIELD	(1 << 4)    /* poll yielded this FP */
-#define BNX2X_FP_OWNED	(BNX2X_FP_STATE_NAPI | BNX2X_FP_STATE_POLL)
-#define BNX2X_FP_YIELD	(BNX2X_FP_STATE_NAPI_YIELD | BNX2X_FP_STATE_POLL_YIELD)
-#define BNX2X_FP_LOCKED	(BNX2X_FP_OWNED | BNX2X_FP_STATE_DISABLED)
-#define BNX2X_FP_USER_PEND (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_POLL_YIELD)
-	/* protect state */
-	spinlock_t lock;
-#endif /* CONFIG_NET_RX_BUSY_POLL */
+	unsigned long		busy_poll_state;
+#endif
 
 	union host_hc_status_block	status_blk;
 	/* chip independent shortcuts into sb structure */
@@ -619,104 +607,83 @@ struct bnx2x_fastpath {
 #define bnx2x_fp_qstats(bp, fp)	(&((bp)->fp_stats[(fp)->index].eth_q_stats))
 
 #ifdef CONFIG_NET_RX_BUSY_POLL
-static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp)
+
+enum bnx2x_fp_state {
+	BNX2X_STATE_FP_NAPI	= BIT(0), /* NAPI handler owns the queue */
+
+	BNX2X_STATE_FP_NAPI_REQ_BIT = 1, /* NAPI would like to own the queue */
+	BNX2X_STATE_FP_NAPI_REQ = BIT(1),
+
+	BNX2X_STATE_FP_POLL_BIT = 2,
+	BNX2X_STATE_FP_POLL     = BIT(2), /* busy_poll owns the queue */
+
+	BNX2X_STATE_FP_DISABLE_BIT = 3, /* queue is dismantled */
+};
+
+static inline void bnx2x_fp_busy_poll_init(struct bnx2x_fastpath *fp)
 {
-	spin_lock_init(&fp->lock);
-	fp->state = BNX2X_FP_STATE_IDLE;
+	WRITE_ONCE(fp->busy_poll_state, 0);
 }
 
 /* called from the device poll routine to get ownership of a FP */
 static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
 {
-	bool rc = true;
-
-	spin_lock_bh(&fp->lock);
-	if (fp->state & BNX2X_FP_LOCKED) {
-		WARN_ON(fp->state & BNX2X_FP_STATE_NAPI);
-		fp->state |= BNX2X_FP_STATE_NAPI_YIELD;
-		rc = false;
-	} else {
-		/* we don't care if someone yielded */
-		fp->state = BNX2X_FP_STATE_NAPI;
+	unsigned long prev, old = READ_ONCE(fp->busy_poll_state);
+
+	while (1) {
+		switch (old) {
+		case BNX2X_STATE_FP_POLL:
+			/* make sure bnx2x_fp_lock_poll() wont starve us */
+			set_bit(BNX2X_STATE_FP_NAPI_REQ_BIT,
+				&fp->busy_poll_state);
+			/* fallthrough */
+		case BNX2X_STATE_FP_POLL | BNX2X_STATE_FP_NAPI_REQ:
+			return false;
+		default:
+			break;
+		}
+		prev = cmpxchg(&fp->busy_poll_state, old, BNX2X_STATE_FP_NAPI);
+		if (unlikely(prev != old)) {
+			old = prev;
+			continue;
+		}
+		return true;
 	}
-	spin_unlock_bh(&fp->lock);
-	return rc;
 }
 
-/* returns true is someone tried to get the FP while napi had it */
-static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
+static inline void bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
 {
-	bool rc = false;
-
-	spin_lock_bh(&fp->lock);
-	WARN_ON(fp->state &
-		(BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_NAPI_YIELD));
-
-	if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
-		rc = true;
-
-	/* state ==> idle, unless currently disabled */
-	fp->state &= BNX2X_FP_STATE_DISABLED;
-	spin_unlock_bh(&fp->lock);
-	return rc;
+	smp_wmb();
+	fp->busy_poll_state = 0;
 }
 
 /* called from bnx2x_low_latency_poll() */
 static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp)
 {
-	bool rc = true;
-
-	spin_lock_bh(&fp->lock);
-	if ((fp->state & BNX2X_FP_LOCKED)) {
-		fp->state |= BNX2X_FP_STATE_POLL_YIELD;
-		rc = false;
-	} else {
-		/* preserve yield marks */
-		fp->state |= BNX2X_FP_STATE_POLL;
-	}
-	spin_unlock_bh(&fp->lock);
-	return rc;
+	return cmpxchg(&fp->busy_poll_state, 0, BNX2X_STATE_FP_POLL) == 0;
 }
 
-/* returns true if someone tried to get the FP while it was locked */
-static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
+static inline void bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
 {
-	bool rc = false;
-
-	spin_lock_bh(&fp->lock);
-	WARN_ON(fp->state & BNX2X_FP_STATE_NAPI);
-
-	if (fp->state & BNX2X_FP_STATE_POLL_YIELD)
-		rc = true;
-
-	/* state ==> idle, unless currently disabled */
-	fp->state &= BNX2X_FP_STATE_DISABLED;
-	spin_unlock_bh(&fp->lock);
-	return rc;
+	smp_mb__before_atomic();
+	clear_bit(BNX2X_STATE_FP_POLL_BIT, &fp->busy_poll_state);
 }
 
-/* true if a socket is polling, even if it did not get the lock */
+/* true if a socket is polling */
 static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)
 {
-	WARN_ON(!(fp->state & BNX2X_FP_OWNED));
-	return fp->state & BNX2X_FP_USER_PEND;
+	return READ_ONCE(fp->busy_poll_state) & BNX2X_STATE_FP_POLL;
 }
 
 /* false if fp is currently owned */
 static inline bool bnx2x_fp_ll_disable(struct bnx2x_fastpath *fp)
 {
-	int rc = true;
-
-	spin_lock_bh(&fp->lock);
-	if (fp->state & BNX2X_FP_OWNED)
-		rc = false;
-	fp->state |= BNX2X_FP_STATE_DISABLED;
-	spin_unlock_bh(&fp->lock);
+	set_bit(BNX2X_STATE_FP_DISABLE_BIT, &fp->busy_poll_state);
+	return !bnx2x_fp_ll_polling(fp);
 
-	return rc;
 }
 #else
-static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp)
+static inline void bnx2x_fp_busy_poll_init(struct bnx2x_fastpath *fp)
 {
 }
 
@@ -725,9 +692,8 @@ static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp)
 	return true;
 }
 
-static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
+static inline void bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp)
 {
-	return false;
 }
 
 static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp)
@@ -735,9 +701,8 @@ static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp)
 	return false;
 }
 
-static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
+static inline void bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp)
 {
-	return false;
 }
 
 static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp)