Simultaneous accesses to MC_STAT h/w shouldn't be allowed since one
collection process stomps on another. There is no good reason for
polling stats in parallel in practice, nevertheless let's add a
protection lock, just for consistency.
Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
drivers/memory/tegra/tegra20.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/memory/tegra/tegra20.c b/drivers/memory/tegra/tegra20.c
index 4659c0cea30d..2db68a913b7a 100644
--- a/drivers/memory/tegra/tegra20.c
+++ b/drivers/memory/tegra/tegra20.c
@@ -5,6 +5,7 @@
#include <linux/bitfield.h>
#include <linux/delay.h>
+#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/string.h>
@@ -55,6 +56,8 @@
/* we store collected statistics as a fixed point values */
#define MC_FX_FRAC_SCALE 100
+static DEFINE_MUTEX(tegra20_mc_stat_lock);
+
struct tegra20_mc_stat_gather {
unsigned int pri_filter;
unsigned int pri_event;
@@ -615,8 +618,12 @@ static int tegra20_mc_stats_show(struct seq_file *s, void
*unused)
if (!stats)
return -ENOMEM;
+ mutex_lock(&tegra20_mc_stat_lock);
+
tegra20_mc_collect_stats(mc, stats);
+ mutex_unlock(&tegra20_mc_stat_lock);
+
seq_puts(s, "Memory client Events Timeout High priority
Bandwidth ARB RW change Successive Page miss\n");
seq_puts(s,
"-----------------------------------------------------------------------------------------------------\n");
--
2.30.2
