freedreno: Drop batch lock

Now that we are not tracking cross-context batch dependencies, there is
no scenario where one context could trigger flushing another context's
batch.  So we can drop the batch lock intended to protect against this.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21274>

src/gallium/drivers/freedreno/a4xx/fd4_query.c

@@ -114,11 +114,10 @@ time_elapsed_enable(struct fd_context *ctx,
     * just hard coded.  If we start exposing more countables than we
     * have counters, we will need to be more clever.
     */
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
    fd_wfi(batch, ring);
    OUT_PKT0(ring, REG_A4XX_CP_PERFCTR_CP_SEL_0, 1);
    OUT_RING(ring, CP_ALWAYS_COUNT);
-   fd_batch_unlock_submit(batch);
    fd_batch_reference(&batch, NULL);
 }
 

src/gallium/drivers/freedreno/a6xx/fd6_blitter.c

@@ -887,8 +887,7 @@ fd6_clear_texture(struct pipe_context *pctx, struct pipe_resource *prsc,
    fd_batch_resource_write(batch, rsc);
    fd_screen_unlock(ctx->screen);
 
-   ASSERTED bool ret = fd_batch_lock_submit(batch);
-   assert(ret);
+   assert(!batch->flushed);
 
    /* Marking the batch as needing flush must come after the batch
     * dependency tracking (resource_read()/resource_write()), as that
@@ -920,8 +919,6 @@ fd6_clear_texture(struct pipe_context *pctx, struct pipe_resource *prsc,
    fd_wfi(batch, batch->draw);
    fd6_cache_inv(batch, batch->draw);
 
-   fd_batch_unlock_submit(batch);
-
    fd_batch_flush(batch);
    fd_batch_reference(&batch, NULL);
 
@@ -1034,8 +1031,7 @@ handle_rgba_blit(struct fd_context *ctx,
 
    fd_screen_unlock(ctx->screen);
 
-   ASSERTED bool ret = fd_batch_lock_submit(batch);
-   assert(ret);
+   assert(!batch->flushed);
 
    /* Marking the batch as needing flush must come after the batch
     * dependency tracking (resource_read()/resource_write()), as that
@@ -1072,8 +1068,6 @@ handle_rgba_blit(struct fd_context *ctx,
    fd_wfi(batch, batch->draw);
    fd6_cache_inv(batch, batch->draw);
 
-   fd_batch_unlock_submit(batch);
-
    fd_batch_flush(batch);
    fd_batch_reference(&batch, NULL);
 

src/gallium/drivers/freedreno/freedreno_batch.c

@@ -134,8 +134,6 @@ fd_batch_create(struct fd_context *ctx, bool nondraw)
    batch->ctx = ctx;
    batch->nondraw = nondraw;
 
-   simple_mtx_init(&batch->submit_lock, mtx_plain);
-
    batch->resources =
       _mesa_set_create(NULL, _mesa_hash_pointer, _mesa_key_pointer_equal);
 
@@ -313,8 +311,6 @@ __fd_batch_destroy_locked(struct fd_batch *batch)
    util_copy_framebuffer_state(&batch->framebuffer, NULL);
    batch_fini(batch);
 
-   simple_mtx_destroy(&batch->submit_lock);
-
    free(batch->key);
    free(batch);
    fd_screen_lock(ctx->screen);
@@ -350,7 +346,7 @@ batch_flush(struct fd_batch *batch) assert_dt
 {
    DBG("%p: needs_flush=%d", batch, batch->needs_flush);
 
-   if (!fd_batch_lock_submit(batch))
+   if (batch->flushed)
       return;
 
    batch->needs_flush = false;
@@ -388,7 +384,6 @@ batch_flush(struct fd_batch *batch) assert_dt
    assert(batch->reference.count > 0);
 
    cleanup_submit(batch);
-   fd_batch_unlock_submit(batch);
 }
 
 /* NOTE: could drop the last ref to batch

src/gallium/drivers/freedreno/freedreno_batch.h

@@ -64,11 +64,6 @@ struct fd_batch {
 
    struct fd_context *ctx;
 
-   /* emit_lock serializes cmdstream emission and flush.  Acquire before
-    * screen->lock.
-    */
-   simple_mtx_t submit_lock;
-
    /* do we need to mem2gmem before rendering.  We don't, if for example,
     * there was a glClear() that invalidated the entire previous buffer
     * contents.  Keep track of which buffer(s) are cleared, or needs
@@ -333,26 +328,6 @@ fd_batch_reference(struct fd_batch **ptr, struct fd_batch *batch)
    *ptr = batch;
 }
 
-static inline void
-fd_batch_unlock_submit(struct fd_batch *batch)
-{
-   simple_mtx_unlock(&batch->submit_lock);
-}
-
-/**
- * Returns true if emit-lock was acquired, false if failed to acquire lock,
- * ie. batch already flushed.
- */
-static inline bool MUST_CHECK
-fd_batch_lock_submit(struct fd_batch *batch)
-{
-   simple_mtx_lock(&batch->submit_lock);
-   bool ret = !batch->flushed;
-   if (!ret)
-      fd_batch_unlock_submit(batch);
-   return ret;
-}
-
 /**
  * Mark the batch as having something worth flushing (rendering, blit, query,
  * etc)

src/gallium/drivers/freedreno/freedreno_context.c

@@ -229,7 +229,7 @@ fd_emit_string_marker(struct pipe_context *pctx, const char *string,
    if (!ctx->batch)
       return;
 
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
 
    fd_batch_needs_flush(batch);
 
@@ -239,7 +239,6 @@ fd_emit_string_marker(struct pipe_context *pctx, const char *string,
       fd_emit_string(batch->draw, string, len);
    }
 
-   fd_batch_unlock_submit(batch);
    fd_batch_reference(&batch, NULL);
 }
 
@@ -353,27 +352,6 @@ fd_context_batch(struct fd_context *ctx)
    return batch;
 }
 
-/**
- * Return a locked reference to the current batch.  A batch with emit
- * lock held is protected against flushing while the lock is held.
- * The emit-lock should be acquired before screen-lock.  The emit-lock
- * should be held while emitting cmdstream.
- */
-struct fd_batch *
-fd_context_batch_locked(struct fd_context *ctx)
-{
-   struct fd_batch *batch = NULL;
-
-   while (!batch) {
-      batch = fd_context_batch(ctx);
-      if (!fd_batch_lock_submit(batch)) {
-         fd_batch_reference(&batch, NULL);
-      }
-   }
-
-   return batch;
-}
-
 /**
  * Return a reference to the current non-draw (compute/blit) batch.
  */

src/gallium/drivers/freedreno/freedreno_draw.c

@@ -353,7 +353,7 @@ fd_draw_vbo(struct pipe_context *pctx, const struct pipe_draw_info *info,
 
    batch_draw_tracking(batch, info, indirect);
 
-   while (unlikely(!fd_batch_lock_submit(batch))) {
+   while (unlikely(batch->flushed)) {
       /* The current batch was flushed in batch_draw_tracking()
        * so start anew.  We know this won't happen a second time
        * since we are dealing with a fresh batch:
@@ -392,7 +392,6 @@ fd_draw_vbo(struct pipe_context *pctx, const struct pipe_draw_info *info,
 
    assert(!batch->flushed);
 
-   fd_batch_unlock_submit(batch);
    fd_batch_check_size(batch);
    fd_batch_reference(&batch, NULL);
 
@@ -480,7 +479,7 @@ fd_clear(struct pipe_context *pctx, unsigned buffers,
 
    batch_clear_tracking(batch, buffers);
 
-   while (unlikely(!fd_batch_lock_submit(batch))) {
+   while (unlikely(batch->flushed)) {
       /* The current batch was flushed in batch_clear_tracking()
        * so start anew.  We know this won't happen a second time
        * since we are dealing with a fresh batch:
@@ -521,8 +520,6 @@ fd_clear(struct pipe_context *pctx, unsigned buffers,
 
    assert(!batch->flushed);
 
-   fd_batch_unlock_submit(batch);
-
    if (fallback) {
       fd_blitter_clear(pctx, buffers, color, depth, stencil);
    }

src/gallium/drivers/freedreno/freedreno_query_acc.c

@@ -114,9 +114,8 @@ fd_acc_begin_query(struct fd_context *ctx, struct fd_query *q) assert_dt
     * need to just emit the capture at this moment.
     */
    if (skip_begin_query(q->type)) {
-      struct fd_batch *batch = fd_context_batch_locked(ctx);
+      struct fd_batch *batch = fd_context_batch(ctx);
       fd_acc_query_resume(aq, batch);
-      fd_batch_unlock_submit(batch);
       fd_batch_reference(&batch, NULL);
    }
 }
@@ -134,7 +133,7 @@ fd_acc_end_query(struct fd_context *ctx, struct fd_query *q) assert_dt
    list_delinit(&aq->node);
 
    /* mark the result available: */
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
    struct fd_ringbuffer *ring = batch->draw;
    struct fd_resource *rsc = fd_resource(aq->prsc);
 
@@ -150,7 +149,6 @@ fd_acc_end_query(struct fd_context *ctx, struct fd_query *q) assert_dt
       OUT_RING(ring, 0);     /* high 32b */
    }
 
-   fd_batch_unlock_submit(batch);
    fd_batch_reference(&batch, NULL);
 }
 
@@ -206,7 +204,7 @@ fd_acc_get_query_result_resource(struct fd_context *ctx, struct fd_query *q,
 {
    struct fd_acc_query *aq = fd_acc_query(q);
    const struct fd_acc_sample_provider *p = aq->provider;
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
 
    assert(ctx->screen->gen >= 5);
 
@@ -243,8 +241,6 @@ fd_acc_get_query_result_resource(struct fd_context *ctx, struct fd_query *q,
       p->result_resource(aq, ring, result_type, index, dst, offset);
    }
 
-   fd_batch_unlock_submit(batch);
-
    /* If we are told to wait for results, then we need to flush.  For an IMR
     * this would just be a wait on the GPU, but the expectation is that draws
     * following this one see the results of the query, which means we need to

src/gallium/drivers/freedreno/freedreno_query_hw.c

@@ -137,7 +137,7 @@ fd_hw_destroy_query(struct fd_context *ctx, struct fd_query *q)
 static void
 fd_hw_begin_query(struct fd_context *ctx, struct fd_query *q) assert_dt
 {
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
    struct fd_hw_query *hq = fd_hw_query(q);
 
    DBG("%p", q);
@@ -152,14 +152,13 @@ fd_hw_begin_query(struct fd_context *ctx, struct fd_query *q) assert_dt
    assert(list_is_empty(&hq->list));
    list_addtail(&hq->list, &ctx->hw_active_queries);
 
-   fd_batch_unlock_submit(batch);
    fd_batch_reference(&batch, NULL);
 }
 
 static void
 fd_hw_end_query(struct fd_context *ctx, struct fd_query *q) assert_dt
 {
-   struct fd_batch *batch = fd_context_batch_locked(ctx);
+   struct fd_batch *batch = fd_context_batch(ctx);
    struct fd_hw_query *hq = fd_hw_query(q);
 
    DBG("%p", q);
@@ -170,7 +169,6 @@ fd_hw_end_query(struct fd_context *ctx, struct fd_query *q) assert_dt
    /* remove from active list: */
    list_delinit(&hq->list);
 
-   fd_batch_unlock_submit(batch);
    fd_batch_reference(&batch, NULL);
 }