gpu: nvgpu: gk20a: add submit_lock

Add submit mutex lock to avoid race conditions between submitting
a job, removing a job and submitting WFI

With this lock make below operations atomic :

during submit_gpfifo() -
1. getting new syncpt
2. inserting syncpt increment
3. submitting gpfifo
4. setting job completion interrupt

during submit_wfi() -
1. getting new syncpt
2. inserting syncpt increment when idle

during channel_update() -
1. checking the submit job completion
2. freeing the job if it is completed

Bug 1305024

Change-Id: I0e3c0b8906d83fd59642344626ffdf24fad2aaab
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/397670
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 43 insertions, 21 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 1570e12c..b7bd55ea 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -1268,12 +1268,6 @@ static int gk20a_channel_submit_wfi(struct channel_gk20a *c)
         if (c->has_timedout)
                 return -ETIMEDOUT;
 
-        if (!c->sync) {
-                c->sync = gk20a_channel_sync_create(c);
-                if (!c->sync)
-                        return -ENOMEM;
-        }
-
         update_gp_get(g, c);
         free_count = gp_free_count(c);
         if (unlikely(!free_count)) {
@@ -1282,9 +1276,21 @@ static int gk20a_channel_submit_wfi(struct channel_gk20a *c)
                 return -EAGAIN;
         }
 
+        mutex_lock(&c->submit_lock);
+
+        if (!c->sync) {
+                c->sync = gk20a_channel_sync_create(c);
+                if (!c->sync) {
+                        mutex_unlock(&c->submit_lock);
+                        return -ENOMEM;
+                }
+        }
+
         err = c->sync->incr_wfi(c->sync, &cmd, &c->last_submit_fence);
-        if (unlikely(err))
+        if (unlikely(err)) {
+                mutex_unlock(&c->submit_lock);
                 return err;
+        }
 
         WARN_ON(!c->last_submit_fence.wfi);
 
@@ -1301,6 +1307,8 @@ static int gk20a_channel_submit_wfi(struct channel_gk20a *c)
                 c->userd_gpu_va + 4 * ram_userd_gp_put_w(),
                 c->gpfifo.put);
 
+        mutex_unlock(&c->submit_lock);
+
         gk20a_dbg_info("post-submit put %d, get %d, size %d",
                 c->gpfifo.put, c->gpfifo.get, c->gpfifo.entry_num);
 
@@ -1393,6 +1401,7 @@ void gk20a_channel_update(struct channel_gk20a *c, int nr_completed)
 
         wake_up(&c->submit_wq);
 
+        mutex_lock(&c->submit_lock);
         mutex_lock(&c->jobs_lock);
         list_for_each_entry_safe(job, n, &c->jobs, list) {
                 bool completed = WARN_ON(!c->sync) ||
@@ -1411,6 +1420,7 @@ void gk20a_channel_update(struct channel_gk20a *c, int nr_completed)
                 gk20a_idle(g->dev);
         }
         mutex_unlock(&c->jobs_lock);
+        mutex_unlock(&c->submit_lock);
 
         for (i = 0; i < nr_completed; i++)
                 gk20a_idle(c->g->dev);
@@ -1452,12 +1462,6 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
             !fence)
                 return -EINVAL;
 
-        if (!c->sync) {
-                c->sync = gk20a_channel_sync_create(c);
-                if (!c->sync)
-                        return -ENOMEM;
-        }
-
 #ifdef CONFIG_DEBUG_FS
         /* update debug settings */
         if (g->ops.ltc.sync_debugfs)
@@ -1510,6 +1514,17 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
                 goto clean_up;
         }
 
+        mutex_lock(&c->submit_lock);
+
+        if (!c->sync) {
+                c->sync = gk20a_channel_sync_create(c);
+                if (!c->sync) {
+                        err = -ENOMEM;
+                        mutex_unlock(&c->submit_lock);
+                        goto clean_up;
+                }
+        }
+
         /*
          * optionally insert syncpt wait in the beginning of gpfifo submission
          * when user requested and the wait hasn't expired.
@@ -1525,8 +1540,10 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
                         err = c->sync->wait_syncpt(c->sync, fence->syncpt_id,
                                         fence->value, &wait_cmd);
         }
-        if (err)
+        if (err) {
+                mutex_unlock(&c->submit_lock);
                 goto clean_up;
+        }
 
 
         /* always insert syncpt increment at end of gpfifo submission
@@ -1544,8 +1561,10 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
         else
                 err = c->sync->incr(c->sync, &incr_cmd,
                                     &c->last_submit_fence);
-        if (err)
+        if (err) {
+                mutex_unlock(&c->submit_lock);
                 goto clean_up;
+        }
 
         if (wait_cmd) {
                 c->gpfifo.cpu_va[c->gpfifo.put].entry0 =
@@ -1587,12 +1606,6 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
                 incr_cmd->gp_put = c->gpfifo.put;
         }
 
-        trace_gk20a_channel_submitted_gpfifo(c->g->dev->name,
-                                             c->hw_chid,
-                                             num_entries,
-                                             flags,
-                                             fence->syncpt_id, fence->value);
-
         /* TODO! Check for errors... */
         gk20a_channel_add_job(c, &c->last_submit_fence);
 
@@ -1601,6 +1614,14 @@ static int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
                 c->userd_gpu_va + 4 * ram_userd_gp_put_w(),
                 c->gpfifo.put);
 
+        mutex_unlock(&c->submit_lock);
+
+        trace_gk20a_channel_submitted_gpfifo(c->g->dev->name,
+                                             c->hw_chid,
+                                             num_entries,
+                                             flags,
+                                             fence->syncpt_id, fence->value);
+
         gk20a_dbg_info("post-submit put %d, get %d, size %d",
                 c->gpfifo.put, c->gpfifo.get, c->gpfifo.entry_num);
 
@@ -1629,6 +1650,7 @@ int gk20a_init_channel_support(struct gk20a *g, u32 chid)
         c->bound = false;
         c->remove_support = gk20a_remove_channel_support;
         mutex_init(&c->jobs_lock);
+        mutex_init(&c->submit_lock);
         INIT_LIST_HEAD(&c->jobs);
 #if defined(CONFIG_GK20A_CYCLE_STATS)
         mutex_init(&c->cyclestate.cyclestate_buffer_mutex);