[PATCH AUTOSEL 6.1 06/58] drm/omap: dsi: Fix excessive stack usage

Sasha Levin
2023-02-27T02:06:31Z

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

[ 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>
---
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 a6845856cbce4..4c1084eb01759 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
--
2.39.0