etnaviv: Add lock around pending_ctx

The content of rsc->pending_ctx could be changed from multiple contexts
and thus from multiple threads. The per-context lock is not sufficient
to protect this list. Add per-resource lock to protect this list.

Fixes: e5cc66dfad0 ("etnaviv: Rework locking")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6454>

4 files changed, 53 insertions, 3 deletions

diff --git a/src/gallium/drivers/etnaviv/etnaviv_context.c b/src/gallium/drivers/etnaviv/etnaviv_context.c
index 4c204fc9d0c..ffe2f32ecff 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_context.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_context.c
@@ -93,6 +93,7 @@ etna_context_destroy(struct pipe_context *pctx)
    struct etna_context *ctx = etna_context(pctx);
 
    mtx_lock(&ctx->lock);
+
    if (ctx->used_resources_read) {
 
       /*
@@ -103,7 +104,9 @@ etna_context_destroy(struct pipe_context *pctx)
       set_foreach(ctx->used_resources_read, entry) {
          struct etna_resource *rsc = (struct etna_resource *)entry->key;
 
+         mtx_lock(&rsc->lock);
          _mesa_set_remove_key(rsc->pending_ctx, ctx);
+         mtx_unlock(&rsc->lock);
       }
       _mesa_set_destroy(ctx->used_resources_read, NULL);
 
@@ -118,7 +121,9 @@ etna_context_destroy(struct pipe_context *pctx)
       set_foreach(ctx->used_resources_write, entry) {
          struct etna_resource *rsc = (struct etna_resource *)entry->key;
 
+         mtx_lock(&rsc->lock);
          _mesa_set_remove_key(rsc->pending_ctx, ctx);
+         mtx_unlock(&rsc->lock);
       }
       _mesa_set_destroy(ctx->used_resources_write, NULL);
 
@@ -484,12 +489,16 @@ etna_flush(struct pipe_context *pctx, struct pipe_fence_handle **fence,
       struct etna_resource *rsc = (struct etna_resource *)entry->key;
       struct pipe_resource *referenced = &rsc->base;
 
+      mtx_lock(&rsc->lock);
+
       _mesa_set_remove_key(rsc->pending_ctx, ctx);
 
       /* if resource has no pending ctx's reset its status */
       if (_mesa_set_next_entry(rsc->pending_ctx, NULL) == NULL)
          rsc->status &= ~ETNA_PENDING_READ;
 
+      mtx_unlock(&rsc->lock);
+
       pipe_resource_reference(&referenced, NULL);
    }
    _mesa_set_clear(ctx->used_resources_read, NULL);
@@ -498,11 +507,13 @@ etna_flush(struct pipe_context *pctx, struct pipe_fence_handle **fence,
       struct etna_resource *rsc = (struct etna_resource *)entry->key;
       struct pipe_resource *referenced = &rsc->base;
 
+      mtx_lock(&rsc->lock);
       _mesa_set_remove_key(rsc->pending_ctx, ctx);
 
       /* if resource has no pending ctx's reset its status */
       if (_mesa_set_next_entry(rsc->pending_ctx, NULL) == NULL)
          rsc->status &= ~ETNA_PENDING_WRITE;
+      mtx_unlock(&rsc->lock);
 
       pipe_resource_reference(&referenced, NULL);
    }
diff --git a/src/gallium/drivers/etnaviv/etnaviv_resource.c b/src/gallium/drivers/etnaviv/etnaviv_resource.c
index 1f763c2b683..e2ef97f286f 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_resource.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_resource.c
@@ -321,6 +321,7 @@ etna_resource_alloc(struct pipe_screen *pscreen, unsigned layout,
       memset(map, 0, size);
    }
 
+   mtx_init(&rsc->lock, mtx_recursive);
    rsc->pending_ctx = _mesa_set_create(NULL, _mesa_hash_pointer,
                                        _mesa_key_pointer_equal);
    if (!rsc->pending_ctx)
@@ -463,8 +464,10 @@ etna_resource_destroy(struct pipe_screen *pscreen, struct pipe_resource *prsc)
 {
    struct etna_resource *rsc = etna_resource(prsc);
 
+   mtx_lock(&rsc->lock);
    assert(!_mesa_set_next_entry(rsc->pending_ctx, NULL));
    _mesa_set_destroy(rsc->pending_ctx, NULL);
+   mtx_unlock(&rsc->lock);
 
    if (rsc->bo)
       etna_bo_del(rsc->bo);
@@ -483,6 +486,8 @@ etna_resource_destroy(struct pipe_screen *pscreen, struct pipe_resource *prsc)
    for (unsigned i = 0; i < ETNA_NUM_LOD; i++)
       FREE(rsc->levels[i].patch_offsets);
 
+   mtx_destroy(&rsc->lock);
+
    FREE(rsc);
 }
 
@@ -559,6 +564,7 @@ etna_resource_from_handle(struct pipe_screen *pscreen,
       goto fail;
    }
 
+   mtx_init(&rsc->lock, mtx_recursive);
    rsc->pending_ctx = _mesa_set_create(NULL, _mesa_hash_pointer,
                                        _mesa_key_pointer_equal);
    if (!rsc->pending_ctx)
@@ -616,18 +622,41 @@ etna_resource_used(struct etna_context *ctx, struct pipe_resource *prsc,
    mtx_lock(&ctx->lock);
 
    rsc = etna_resource(prsc);
+again:
+   mtx_lock(&rsc->lock);
 
    set_foreach(rsc->pending_ctx, entry) {
       struct etna_context *extctx = (struct etna_context *)entry->key;
       struct pipe_context *pctx = &extctx->base;
+      bool need_flush = false;
+
+      if (mtx_trylock(&extctx->lock) != thrd_success) {
+         /*
+	  * The other context could be locked in etna_flush() and
+	  * stuck waiting for the resource lock, so release the
+	  * resource lock here, let etna_flush() finish, and try
+	  * again.
+	  */
+         mtx_unlock(&rsc->lock);
+         thrd_yield();
+         goto again;
+      }
 
       set_foreach(extctx->used_resources_read, entry2) {
          struct etna_resource *rsc2 = (struct etna_resource *)entry2->key;
          if (ctx == extctx || rsc2 != rsc)
             continue;
 
-         if (status & ETNA_PENDING_WRITE)
-            pctx->flush(pctx, NULL, 0);
+         if (status & ETNA_PENDING_WRITE) {
+            need_flush = true;
+            break;
+         }
+      }
+
+      if (need_flush) {
+         pctx->flush(pctx, NULL, 0);
+         mtx_unlock(&extctx->lock);
+	 continue;
       }
 
       set_foreach(extctx->used_resources_write, entry2) {
@@ -635,8 +664,14 @@ etna_resource_used(struct etna_context *ctx, struct pipe_resource *prsc,
          if (ctx == extctx || rsc2 != rsc)
             continue;
 
-         pctx->flush(pctx, NULL, 0);
+         need_flush = true;
+         break;
       }
+
+      if (need_flush)
+         pctx->flush(pctx, NULL, 0);
+
+      mtx_unlock(&extctx->lock);
    }
 
    rsc->status = status;
@@ -648,6 +683,7 @@ etna_resource_used(struct etna_context *ctx, struct pipe_resource *prsc,
       _mesa_set_add(rsc->pending_ctx, ctx);
    }
 
+   mtx_unlock(&rsc->lock);
    mtx_unlock(&ctx->lock);
 }
 
diff --git a/src/gallium/drivers/etnaviv/etnaviv_resource.h b/src/gallium/drivers/etnaviv/etnaviv_resource.h
index 25d263db1ec..cb83e891d34 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_resource.h
+++ b/src/gallium/drivers/etnaviv/etnaviv_resource.h
@@ -96,6 +96,7 @@ struct etna_resource {
 
    enum etna_resource_status status;
 
+   mtx_t lock; /* Lock to protect pending_ctx */
    struct set *pending_ctx;
 };
 
diff --git a/src/gallium/drivers/etnaviv/etnaviv_transfer.c b/src/gallium/drivers/etnaviv/etnaviv_transfer.c
index 0d0324ec0cb..27f3ebe585b 100644
--- a/src/gallium/drivers/etnaviv/etnaviv_transfer.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_transfer.c
@@ -391,12 +391,14 @@ etna_transfer_map(struct pipe_context *pctx, struct pipe_resource *prsc,
           (!trans->rsc &&
            (((usage & PIPE_TRANSFER_READ) && (rsc->status & ETNA_PENDING_WRITE)) ||
            ((usage & PIPE_TRANSFER_WRITE) && rsc->status)))) {
+         mtx_lock(&rsc->lock);
          set_foreach(rsc->pending_ctx, entry) {
             struct etna_context *pend_ctx = (struct etna_context *)entry->key;
             struct pipe_context *pend_pctx = &pend_ctx->base;
 
             pend_pctx->flush(pend_pctx, NULL, 0);
          }
+         mtx_unlock(&rsc->lock);
       }
 
       mtx_unlock(&ctx->lock);