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authorDmitry Osipenko <digetx@gmail.com>2021-03-24 00:04:46 +0300
committerKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>2021-04-01 19:58:22 +0200
commit289471984f1c226c9e0e50d31d0db6b3678e6f5a (patch)
treed01b55ecc1dde7f67c75f6154192a3ecd9ae7baa /drivers/memory/tegra
parent7ebb09db5b265701b70a4c8980513825dbc57584 (diff)
memory: tegra20: Protect debug code with a lock
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 <digetx@gmail.com> Link: https://lore.kernel.org/r/20210323210446.24867-2-digetx@gmail.com Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Diffstat (limited to 'drivers/memory/tegra')
-rw-r--r--drivers/memory/tegra/tegra20.c7
1 files changed, 7 insertions, 0 deletions
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");