gpu: nvgpu: use spinlock for ch timeout lock

The channel timeout lock guards a very small critical section. Use a
spinlock instead of a mutex for performance.

Bug 1795076

Change-Id: I94940f3fbe84ed539bcf1bc76ca6ae7a0ef2fe13
Signed-off-by: Aingara Paramakuru <aparamakuru@nvidia.com>
Reviewed-on: http://git-master/r/1200803
(cherry picked from commit 4fa9e973da141067be145d9eba2ea74e96869dcd)
Reviewed-on: http://git-master/r/1203799
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

2 files changed, 16 insertions, 16 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index d23a8026..4c03f955 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -1660,35 +1660,35 @@ static void gk20a_channel_timeout_start(struct channel_gk20a *ch,
         if (!ch->wdt_enabled)
                 return;
 
-        mutex_lock(&ch->timeout.lock);
+        raw_spin_lock(&ch->timeout.lock);
 
         if (ch->timeout.initialized) {
-                mutex_unlock(&ch->timeout.lock);
+                raw_spin_unlock(&ch->timeout.lock);
                 return;
         }
 
         ch->timeout.job = job;
         ch->timeout.initialized = true;
+        raw_spin_unlock(&ch->timeout.lock);
+
         schedule_delayed_work(&ch->timeout.wq,
                msecs_to_jiffies(gk20a_get_channel_watchdog_timeout(ch)));
-
-        mutex_unlock(&ch->timeout.lock);
 }
 
 static void gk20a_channel_timeout_stop(struct channel_gk20a *ch)
 {
-        mutex_lock(&ch->timeout.lock);
+        raw_spin_lock(&ch->timeout.lock);
         if (!ch->timeout.initialized) {
-                mutex_unlock(&ch->timeout.lock);
+                raw_spin_unlock(&ch->timeout.lock);
                 return;
         }
-        mutex_unlock(&ch->timeout.lock);
+        raw_spin_unlock(&ch->timeout.lock);
 
         cancel_delayed_work_sync(&ch->timeout.wq);
 
-        mutex_lock(&ch->timeout.lock);
+        raw_spin_lock(&ch->timeout.lock);
         ch->timeout.initialized = false;
-        mutex_unlock(&ch->timeout.lock);
+        raw_spin_unlock(&ch->timeout.lock);
 }
 
 void gk20a_channel_timeout_restart_all_channels(struct gk20a *g)
@@ -1700,13 +1700,13 @@ void gk20a_channel_timeout_restart_all_channels(struct gk20a *g)
                 struct channel_gk20a *ch = &f->channel[chid];
 
                 if (gk20a_channel_get(ch)) {
-                        mutex_lock(&ch->timeout.lock);
+                        raw_spin_lock(&ch->timeout.lock);
                         if (!ch->timeout.initialized) {
-                                mutex_unlock(&ch->timeout.lock);
+                                raw_spin_unlock(&ch->timeout.lock);
                                 gk20a_channel_put(ch);
                                 continue;
                         }
-                        mutex_unlock(&ch->timeout.lock);
+                        raw_spin_unlock(&ch->timeout.lock);
 
                         cancel_delayed_work_sync(&ch->timeout.wq);
                         if (!ch->has_timedout)
@@ -1740,10 +1740,10 @@ static void gk20a_channel_timeout_handler(struct work_struct *work)
                   ch->hw_chid);
 
         /* Get timed out job and reset the timer */
-        mutex_lock(&ch->timeout.lock);
+        raw_spin_lock(&ch->timeout.lock);
         job = ch->timeout.job;
         ch->timeout.initialized = false;
-        mutex_unlock(&ch->timeout.lock);
+        raw_spin_unlock(&ch->timeout.lock);
 
         if (gk20a_fence_is_expired(job->post_fence)) {
                 gk20a_err(dev_from_gk20a(g),
@@ -2333,7 +2333,7 @@ int gk20a_init_channel_support(struct gk20a *g, u32 chid)
         mutex_init(&c->ioctl_lock);
         spin_lock_init(&c->jobs_lock);
         mutex_init(&c->last_submit.fence_lock);
-        mutex_init(&c->timeout.lock);
+        raw_spin_lock_init(&c->timeout.lock);
         mutex_init(&c->sync_lock);
         INIT_DELAYED_WORK(&c->timeout.wq, gk20a_channel_timeout_handler);
         INIT_DELAYED_WORK(&c->clean_up.wq, gk20a_channel_clean_up_jobs);
diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
index 4b2019dd..5ad23bab 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
@@ -72,7 +72,7 @@ struct channel_gk20a_job {
 
 struct channel_gk20a_timeout {
         struct delayed_work wq;
-        struct mutex lock;
+        raw_spinlock_t lock;
         bool initialized;
         struct channel_gk20a_job *job;
 };