From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Date: Fri, 16 Sep 2022 11:22:05 +0300

Subject: [PATCH] drm/omap: dsi: Fix excessive stack usage

References: bsc#1012628

Patch-mainline: 6.2.3

Git-commit: cfca78971b9233aef0891507a98fba62046d4542

[ Upstream commit cfca78971b9233aef0891507a98fba62046d4542 ]

dsi_dump_dsi_irqs(), a function used for debugfs prints, has a large

struct in its frame, which can result in:

drivers/gpu/drm/omapdrm/dss/dsi.c:1126:1: warning: the frame size of 1060 bytes is larger than 1024 bytes [-Wframe-larger-than=]

As the performance of the function is of no concern, let's allocate the

struct with kmalloc instead.

Compile-tested only.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Reported-by: kernel test robot <lkp@intel.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Link: https://patchwork.freedesktop.org/patch/msgid/20220916082206.167427-1-tomi.valkeinen@ideasonboard.com

Signed-off-by: Sasha Levin <sashal@kernel.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 drivers/gpu/drm/omapdrm/dss/dsi.c | 26 ++++++++++++++++----------

 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c

index a6845856..4c1084eb 100644

--- a/drivers/gpu/drm/omapdrm/dss/dsi.c

+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c

@@ -1039,22 +1039,26 @@ static int dsi_dump_dsi_irqs(struct seq_file *s, void *p)

 {

 	struct dsi_data *dsi = s->private;

 	unsigned long flags;

-	struct dsi_irq_stats stats;

+	struct dsi_irq_stats *stats;

+

+	stats = kmalloc(sizeof(*stats), GFP_KERNEL);

+	if (!stats)

+		return -ENOMEM;

 	spin_lock_irqsave(&dsi->irq_stats_lock, flags);

-	stats = dsi->irq_stats;

+	*stats = dsi->irq_stats;

 	memset(&dsi->irq_stats, 0, sizeof(dsi->irq_stats));

 	dsi->irq_stats.last_reset = jiffies;

 	spin_unlock_irqrestore(&dsi->irq_stats_lock, flags);

 	seq_printf(s, "period %u ms\n",

-			jiffies_to_msecs(jiffies - stats.last_reset));

+			jiffies_to_msecs(jiffies - stats->last_reset));

-	seq_printf(s, "irqs %d\n", stats.irq_count);

+	seq_printf(s, "irqs %d\n", stats->irq_count);

 #define PIS(x) \

-	seq_printf(s, "%-20s %10d\n", #x, stats.dsi_irqs[ffs(DSI_IRQ_##x)-1]);

+	seq_printf(s, "%-20s %10d\n", #x, stats->dsi_irqs[ffs(DSI_IRQ_##x)-1]);

 	seq_printf(s, "-- DSI%d interrupts --\n", dsi->module_id + 1);

 	PIS(VC0);

@@ -1078,10 +1082,10 @@ static int dsi_dump_dsi_irqs(struct seq_file *s, void *p)

 #define PIS(x) \

 	seq_printf(s, "%-20s %10d %10d %10d %10d\n", #x, \

-			stats.vc_irqs[0][ffs(DSI_VC_IRQ_##x)-1], \

-			stats.vc_irqs[1][ffs(DSI_VC_IRQ_##x)-1], \

-			stats.vc_irqs[2][ffs(DSI_VC_IRQ_##x)-1], \

-			stats.vc_irqs[3][ffs(DSI_VC_IRQ_##x)-1]);

+			stats->vc_irqs[0][ffs(DSI_VC_IRQ_##x)-1], \

+			stats->vc_irqs[1][ffs(DSI_VC_IRQ_##x)-1], \

+			stats->vc_irqs[2][ffs(DSI_VC_IRQ_##x)-1], \

+			stats->vc_irqs[3][ffs(DSI_VC_IRQ_##x)-1]);

 	seq_printf(s, "-- VC interrupts --\n");

 	PIS(CS);

@@ -1097,7 +1101,7 @@ static int dsi_dump_dsi_irqs(struct seq_file *s, void *p)

 #define PIS(x) \

 	seq_printf(s, "%-20s %10d\n", #x, \

-			stats.cio_irqs[ffs(DSI_CIO_IRQ_##x)-1]);

+			stats->cio_irqs[ffs(DSI_CIO_IRQ_##x)-1]);

 	seq_printf(s, "-- CIO interrupts --\n");

 	PIS(ERRSYNCESC1);

@@ -1122,6 +1126,8 @@ static int dsi_dump_dsi_irqs(struct seq_file *s, void *p)

 	PIS(ULPSACTIVENOT_ALL1);

 #undef PIS

+	kfree(stats);

+

 	return 0;

 }

 #endif

-- 

2.35.3