gpu: nvgpu: acquire mutex for notifier read

We use &ch->error_notifier_mutex to protect
writes and free of error notifier
But we currently do not protect reading of
notifier in gk20a_fifo_set_ctx_mmu_error()
and vgpu_fifo_set_ctx_mmu_error()

Add new API gk20a_set_error_notifier_locked()
which is same as gk20a_set_error_notifier()
but without the locks.

In *_fifo_set_ctx_mmu_error() APIs, acquire
the mutex explicitly, and then use this new
API

gk20a_set_error_notifier() will now just call
gk20a_set_error_notifier_locked() within
a mutex

Bug 1824788
Bug 1844312

Change-Id: I1f3831dc63fe1daa761b2e17e4de3c155f505d6f
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1273471
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Richard Zhao <rizhao@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

1 files changed, 13 insertions, 9 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 129921ad..38cb368c 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -827,11 +827,12 @@ static int gk20a_init_error_notifier(struct channel_gk20a *ch,
         return 0;
 }
 
-void gk20a_set_error_notifier(struct channel_gk20a *ch, __u32 error)
+/**
+ * gk20a_set_error_notifier_locked()
+ * Should be called with ch->error_notifier_mutex held
+ */
+void gk20a_set_error_notifier_locked(struct channel_gk20a *ch, __u32 error)
 {
-        bool notifier_set = false;
-
-        mutex_lock(&ch->error_notifier_mutex);
         if (ch->error_notifier_ref) {
                 struct timespec time_data;
                 u64 nsec;
@@ -845,13 +846,16 @@ void gk20a_set_error_notifier(struct channel_gk20a *ch, __u32 error)
                 ch->error_notifier->info32 = error;
                 ch->error_notifier->status = 0xffff;
 
-                notifier_set = true;
-        }
-        mutex_unlock(&ch->error_notifier_mutex);
-
-        if (notifier_set)
                 gk20a_err(dev_from_gk20a(ch->g),
                     "error notifier set to %d for ch %d", error, ch->hw_chid);
+        }
+}
+
+void gk20a_set_error_notifier(struct channel_gk20a *ch, __u32 error)
+{
+        mutex_lock(&ch->error_notifier_mutex);
+        gk20a_set_error_notifier_locked(ch, error);
+        mutex_unlock(&ch->error_notifier_mutex);
 }
 
 static void gk20a_free_error_notifiers(struct channel_gk20a *ch)