usb: dwc3: gadget: Fix BUG in RT config

Roger Quadros · nsekhar · commit 4996a1e78360 · 2015-09-30T15:53:41.000+05:30
commit a66c275 upstream. Using spin_lock() in hard irq handler is pointless and causes a BUG() in RT (real-time) configuration so get rid of it. The reason it's pointless is because the driver is basically accessing register which is, anyways, atomic. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
@@ -2775,8 +2775,6 @@ static irqreturn_t dwc3_interrupt(int irq, void *_dwc)
 	int				i;
 	irqreturn_t			ret = IRQ_NONE;
 
-	spin_lock(&dwc->lock);
-
 	for (i = 0; i < dwc->num_event_buffers; i++) {
 		irqreturn_t status;
 
@@ -2785,8 +2783,6 @@ static irqreturn_t dwc3_interrupt(int irq, void *_dwc)
 			ret = status;
 	}
 
-	spin_unlock(&dwc->lock);
-
 	return ret;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -2775,8 +2775,6 @@ static irqreturn_t dwc3_interrupt(int irq, void *_dwc)`
`2775`	`2775`	`int i;`
`2776`	`2776`	`irqreturn_t ret = IRQ_NONE;`
`2777`	`2777`
`2778`		`- spin_lock(&dwc->lock);`
`2779`		`-`
`2780`	`2778`	`for (i = 0; i < dwc->num_event_buffers; i++) {`
`2781`	`2779`	`irqreturn_t status;`
`2782`	`2780`
`@@ -2785,8 +2783,6 @@ static irqreturn_t dwc3_interrupt(int irq, void *_dwc)`
`2785`	`2783`	`ret = status;`
`2786`	`2784`	`}`
`2787`	`2785`
`2788`		`- spin_unlock(&dwc->lock);`
`2789`		`-`
`2790`	`2786`	`return ret;`
`2791`	`2787`	`}`
`2792`	`2788`