gallium/u_threaded: Add helper to assert driver thread

Useful for drivers to add some sanity checks to avoid/detect threading
issues caused by things that might be called (indirectly) from frontend
thread.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9323>

src/gallium/auxiliary/util/u_threaded_context.c

@@ -82,10 +82,26 @@ tc_debug_check(struct threaded_context *tc)
 {
    for (unsigned i = 0; i < TC_MAX_BATCHES; i++) {
       tc_batch_check(&tc->batch_slots[i]);
-      tc_assert(tc->batch_slots[i].pipe == tc->pipe);
+      tc_assert(tc->batch_slots[i].tc == tc);
    }
 }
 
+static void
+tc_set_driver_thread(struct threaded_context *tc)
+{
+#ifndef NDEBUG
+   tc->driver_thread = util_get_thread_id();
+#endif
+}
+
+static void
+tc_clear_driver_thread(struct threaded_context *tc)
+{
+#ifndef NDEBUG
+   memset(&tc->driver_thread, 0, sizeof(tc->driver_thread));
+#endif
+}
+
 /* We don't want to read or write min_index and max_index, because
  * it shouldn't be needed by drivers at this point.
  */
@@ -148,10 +164,11 @@ static void
 tc_batch_execute(void *job, UNUSED int thread_index)
 {
    struct tc_batch *batch = job;
-   struct pipe_context *pipe = batch->pipe;
+   struct pipe_context *pipe = batch->tc->pipe;
    struct tc_call *last = &batch->call[batch->num_total_call_slots];
 
    tc_batch_check(batch);
+   tc_set_driver_thread(batch->tc);
 
    assert(!batch->token);
 
@@ -210,6 +227,7 @@ tc_batch_execute(void *job, UNUSED int thread_index)
       iter += iter->num_call_slots;
    }
 
+   tc_clear_driver_thread(batch->tc);
    tc_batch_check(batch);
    batch->num_total_call_slots = 0;
 }
@@ -544,12 +562,18 @@ tc_get_query_result(struct pipe_context *_pipe,
    struct threaded_context *tc = threaded_context(_pipe);
    struct threaded_query *tq = threaded_query(query);
    struct pipe_context *pipe = tc->pipe;
+   bool flushed = tq->flushed;
 
-   if (!tq->flushed)
+   if (!flushed) {
       tc_sync_msg(tc, wait ? "wait" : "nowait");
+      tc_set_driver_thread(tc);
+   }
 
    bool success = pipe->get_query_result(pipe, query, wait, result);
 
+   if (!flushed)
+      tc_clear_driver_thread(tc);
+
    if (success) {
       tq->flushed = true;
       if (list_is_linked(&tq->head_unflushed)) {
@@ -1691,12 +1715,18 @@ tc_transfer_map(struct pipe_context *_pipe,
       tc_sync_msg(tc, resource->target != PIPE_BUFFER ? "  texture" :
                       usage & PIPE_MAP_DISCARD_RANGE ? "  discard_range" :
                       usage & PIPE_MAP_READ ? "  read" : "  staging conflict");
+      tc_set_driver_thread(tc);
    }
 
    tc->bytes_mapped_estimate += box->width;
 
-   return pipe->transfer_map(pipe, tres->latest ? tres->latest : resource,
+   void *ret = pipe->transfer_map(pipe, tres->latest ? tres->latest : resource,
                              level, usage, box, transfer);
+
+   if (!(usage & TC_TRANSFER_MAP_THREADED_UNSYNC))
+      tc_clear_driver_thread(tc);
+
+   return ret;
 }
 
 struct tc_transfer_flush_region {
@@ -1991,8 +2021,10 @@ tc_texture_subdata(struct pipe_context *_pipe,
       struct pipe_context *pipe = tc->pipe;
 
       tc_sync(tc);
+      tc_set_driver_thread(tc);
       pipe->texture_subdata(pipe, resource, level, usage, box, data,
                             stride, layer_stride);
+      tc_clear_driver_thread(tc);
    }
 }
 
@@ -2319,7 +2351,9 @@ out_of_memory:
 
    if (!(flags & PIPE_FLUSH_DEFERRED))
       tc_flush_queries(tc);
+   tc_set_driver_thread(tc);
    pipe->flush(pipe, fence, flags);
+   tc_clear_driver_thread(tc);
 }
 
 static void
@@ -3034,7 +3068,7 @@ threaded_context_create(struct pipe_context *pipe,
 
    for (unsigned i = 0; i < TC_MAX_BATCHES; i++) {
       tc->batch_slots[i].sentinel = TC_SENTINEL;
-      tc->batch_slots[i].pipe = pipe;
+      tc->batch_slots[i].tc = tc;
       util_queue_fence_init(&tc->batch_slots[i].fence);
    }
 

src/gallium/auxiliary/util/u_threaded_context.h

@@ -181,11 +181,13 @@
 #ifndef U_THREADED_CONTEXT_H
 #define U_THREADED_CONTEXT_H
 
+#include "c11/threads.h"
 #include "pipe/p_context.h"
 #include "pipe/p_state.h"
 #include "util/u_inlines.h"
 #include "util/u_queue.h"
 #include "util/u_range.h"
+#include "util/u_thread.h"
 #include "util/slab.h"
 
 struct threaded_context;
@@ -341,7 +343,7 @@ struct tc_unflushed_batch_token {
 };
 
 struct tc_batch {
-   struct pipe_context *pipe;
+   struct threaded_context *tc;
    unsigned sentinel;
    unsigned num_total_call_slots;
    struct tc_unflushed_batch_token *token;
@@ -376,6 +378,15 @@ struct threaded_context {
    struct util_queue queue;
    struct util_queue_fence *fence;
 
+#ifndef NDEBUG
+   /**
+    * The driver thread is normally the queue thread, but
+    * there are cases where the queue is flushed directly
+    * from the frontend thread
+    */
+   thread_id driver_thread;
+#endif
+
    unsigned last, next;
    struct tc_batch batch_slots[TC_MAX_BATCHES];
 };
@@ -435,4 +446,20 @@ tc_unflushed_batch_token_reference(struct tc_unflushed_batch_token **dst,
    *dst = src;
 }
 
+/**
+ * Helper for !NDEBUG builds to assert that it is called from driver
+ * thread.  This is to help drivers ensure that various code-paths
+ * are not hit indirectly from pipe entry points that are called from
+ * front-end/state-tracker thread.
+ */
+static inline void
+tc_assert_driver_thread(struct threaded_context *tc)
+{
+   if (!tc)
+      return;
+#ifndef NDEBUG
+   assert(util_thread_id_equal(tc->driver_thread, util_get_thread_id()));
+#endif
+}
+
 #endif