linux-kernel - [PATCH v2 6/6] drm/lima: handle shared irq case for lima_pp_bcast_irq

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Date:   Fri, 19 Apr 2019 09:33:01 +0100
From:   Peter Griffin <peter.griffin@...aro.org>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        john.stultz@...aro.org, airlied@...ux.ie, daniel@...ll.ch,
        robh+dt@...nel.org, mark.rutland@....com, p.zabel@...gutronix.de,
        xuwei5@...ilicon.com, mturquette@...libre.com, sboyd@...nel.org,
        yuq825@...il.com
Cc:     dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-clk@...r.kernel.org, lima@...ts.freedesktop.org,
        Rob Herring <robh@...nel.org>
Subject: [PATCH v2 6/6] drm/lima: handle shared irq case for lima_pp_bcast_irq_handler

On Hikey board all lima ip blocks are shared with one irq.
This patch avoids a NULL ptr deref crash on this platform
on startup. Tested with Weston and kmscube.

Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
Cc: Rob Herring <robh@...nel.org>
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: Qiang Yu <yuq825@...il.com>
---
 drivers/gpu/drm/lima/lima_pp.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/lima/lima_pp.c b/drivers/gpu/drm/lima/lima_pp.c
index d29721e..8fef224 100644
--- a/drivers/gpu/drm/lima/lima_pp.c
+++ b/drivers/gpu/drm/lima/lima_pp.c
@@ -64,7 +64,13 @@ static irqreturn_t lima_pp_bcast_irq_handler(int irq, void *data)
 	struct lima_ip *pp_bcast = data;
 	struct lima_device *dev = pp_bcast->dev;
 	struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_pp;
-	struct drm_lima_m450_pp_frame *frame = pipe->current_task->frame;
+	struct drm_lima_m450_pp_frame *frame;
+
+	/* for shared irq case */
+	if (!pipe->current_task)
+		return IRQ_NONE;
+
+	frame = pipe->current_task->frame;
 
 	for (i = 0; i < frame->num_pp; i++) {
 		struct lima_ip *ip = pipe->processor[i];
-- 
2.7.4