binder: change binder_stats to atomics

Use atomics for stats to avoid needing to lock for
increments/decrements

Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 20 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index fb484c6acd3e..cd4191d027e1 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -167,22 +167,22 @@ enum binder_stat_types {
 };
 
 struct binder_stats {
-        int br[_IOC_NR(BR_FAILED_REPLY) + 1];
-        int bc[_IOC_NR(BC_REPLY_SG) + 1];
-        int obj_created[BINDER_STAT_COUNT];
-        int obj_deleted[BINDER_STAT_COUNT];
+        atomic_t br[_IOC_NR(BR_FAILED_REPLY) + 1];
+        atomic_t bc[_IOC_NR(BC_REPLY_SG) + 1];
+        atomic_t obj_created[BINDER_STAT_COUNT];
+        atomic_t obj_deleted[BINDER_STAT_COUNT];
 };
 
 static struct binder_stats binder_stats;
 
 static inline void binder_stats_deleted(enum binder_stat_types type)
 {
-        binder_stats.obj_deleted[type]++;
+        atomic_inc(&binder_stats.obj_deleted[type]);
 }
 
 static inline void binder_stats_created(enum binder_stat_types type)
 {
-        binder_stats.obj_created[type]++;
+        atomic_inc(&binder_stats.obj_created[type]);
 }
 
 struct binder_transaction_log_entry {
@@ -1825,9 +1825,9 @@ static int binder_thread_write(struct binder_proc *proc,
                 ptr += sizeof(uint32_t);
                 trace_binder_command(cmd);
                 if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.bc)) {
-                        binder_stats.bc[_IOC_NR(cmd)]++;
-                        proc->stats.bc[_IOC_NR(cmd)]++;
-                        thread->stats.bc[_IOC_NR(cmd)]++;
+                        atomic_inc(&binder_stats.bc[_IOC_NR(cmd)]);
+                        atomic_inc(&proc->stats.bc[_IOC_NR(cmd)]);
+                        atomic_inc(&thread->stats.bc[_IOC_NR(cmd)]);
                 }
                 switch (cmd) {
                 case BC_INCREFS:
@@ -2201,9 +2201,9 @@ static void binder_stat_br(struct binder_proc *proc,
 {
         trace_binder_return(cmd);
         if (_IOC_NR(cmd) < ARRAY_SIZE(binder_stats.br)) {
-                binder_stats.br[_IOC_NR(cmd)]++;
-                proc->stats.br[_IOC_NR(cmd)]++;
-                thread->stats.br[_IOC_NR(cmd)]++;
+                atomic_inc(&binder_stats.br[_IOC_NR(cmd)]);
+                atomic_inc(&proc->stats.br[_IOC_NR(cmd)]);
+                atomic_inc(&thread->stats.br[_IOC_NR(cmd)]);
         }
 }
 
@@ -3453,17 +3453,21 @@ static void print_binder_stats(struct seq_file *m, const char *prefix,
         BUILD_BUG_ON(ARRAY_SIZE(stats->bc) !=
                      ARRAY_SIZE(binder_command_strings));
         for (i = 0; i < ARRAY_SIZE(stats->bc); i++) {
-                if (stats->bc[i])
+                int temp = atomic_read(&stats->bc[i]);
+
+                if (temp)
                         seq_printf(m, "%s%s: %d\n", prefix,
-                                   binder_command_strings[i], stats->bc[i]);
+                                   binder_command_strings[i], temp);
         }
 
         BUILD_BUG_ON(ARRAY_SIZE(stats->br) !=
                      ARRAY_SIZE(binder_return_strings));
         for (i = 0; i < ARRAY_SIZE(stats->br); i++) {
-                if (stats->br[i])
+                int temp = atomic_read(&stats->br[i]);
+
+                if (temp)
                         seq_printf(m, "%s%s: %d\n", prefix,
-                                   binder_return_strings[i], stats->br[i]);
+                                   binder_return_strings[i], temp);
         }
 
         BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
@@ -3471,11 +3475,15 @@ static void print_binder_stats(struct seq_file *m, const char *prefix,
         BUILD_BUG_ON(ARRAY_SIZE(stats->obj_created) !=
                      ARRAY_SIZE(stats->obj_deleted));
         for (i = 0; i < ARRAY_SIZE(stats->obj_created); i++) {
-                if (stats->obj_created[i] || stats->obj_deleted[i])
-                        seq_printf(m, "%s%s: active %d total %d\n", prefix,
+                int created = atomic_read(&stats->obj_created[i]);
+                int deleted = atomic_read(&stats->obj_deleted[i]);
+
+                if (created || deleted)
+                        seq_printf(m, "%s%s: active %d total %d\n",
+                                prefix,
                                 binder_objstat_strings[i],
-                                stats->obj_created[i] - stats->obj_deleted[i],
-                                stats->obj_created[i]);
+                                created - deleted,
+                                created);
         }
 }