linux-kernel - [PATCH 3.2 029/106] usb: host: xhci: simplify irq handler return

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Date:   Sat, 09 Sep 2017 22:47:39 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Mathias Nyman" <mathias.nyman@...ux.intel.com>,
        "Felipe Balbi" <felipe.balbi@...ux.intel.com>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>
Subject: [PATCH 3.2 029/106] usb: host: xhci: simplify irq handler return

3.2.93-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Felipe Balbi <felipe.balbi@...ux.intel.com>

commit 76a35293b901915c5dcb4a87a4a0da8d7caf39fe upstream.

Instead of having several return points, let's use a local variable and
a single place to return. This makes the code slightly easier to read.

[set ret = IRQ_HANDLED in default working case  -Mathias]
Signed-off-by: Felipe Balbi <felipe.balbi@...ux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/usb/host/xhci-ring.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2642,29 +2642,30 @@ static int xhci_handle_event(struct xhci
 irqreturn_t xhci_irq(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	u32 status;
 	union xhci_trb *trb;
-	u64 temp_64;
 	union xhci_trb *event_ring_deq;
+	irqreturn_t ret = IRQ_NONE;
 	dma_addr_t deq;
+	u64 temp_64;
+	u32 status;
 
 	spin_lock(&xhci->lock);
 	trb = xhci->event_ring->dequeue;
 	/* Check if the xHC generated the interrupt, or the irq is shared */
 	status = xhci_readl(xhci, &xhci->op_regs->status);
-	if (status == 0xffffffff)
-		goto hw_died;
-
-	if (!(status & STS_EINT)) {
-		spin_unlock(&xhci->lock);
-		return IRQ_NONE;
+	if (status == 0xffffffff) {
+		ret = IRQ_HANDLED;
+		goto out;
 	}
+
+	if (!(status & STS_EINT))
+		goto out;
+
 	if (status & STS_FATAL) {
 		xhci_warn(xhci, "WARNING: Host System Error\n");
 		xhci_halt(xhci);
-hw_died:
-		spin_unlock(&xhci->lock);
-		return IRQ_HANDLED;
+		ret = IRQ_HANDLED;
+		goto out;
 	}
 
 	/*
@@ -2694,9 +2695,8 @@ hw_died:
 		temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
 		xhci_write_64(xhci, temp_64 | ERST_EHB,
 				&xhci->ir_set->erst_dequeue);
-		spin_unlock(&xhci->lock);
-
-		return IRQ_HANDLED;
+		ret = IRQ_HANDLED;
+		goto out;
 	}
 
 	event_ring_deq = xhci->event_ring->dequeue;
@@ -2721,10 +2721,12 @@ hw_died:
 	/* Clear the event handler busy flag (RW1C); event ring is empty. */
 	temp_64 |= ERST_EHB;
 	xhci_write_64(xhci, temp_64, &xhci->ir_set->erst_dequeue);
+	ret = IRQ_HANDLED;
 
+out:
 	spin_unlock(&xhci->lock);
 
-	return IRQ_HANDLED;
+	return ret;
 }
 
 irqreturn_t xhci_msi_irq(int irq, struct usb_hcd *hcd)