From 864f0c2ede423f64c01f19d4803aabe7b9cfa244 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADctor=20Manuel=20J=C3=A1quez=20Leal?=
 <vjaquez@igalia.com>
Date: Mon, 28 Sep 2020 16:59:44 +0200
Subject: [PATCH] va: allocator: make GstVaMemory shareable

Renamed the first variable member of GstVaMemory from parent to mem in
order to avoid confusion with GstMemory's parent.

When freeing the structure, memory's parent is check in order to
decide if surfaces has to be destroyed or not, since only the parent
class have to destroy it.

Removed GST_MEMORY_FLAG_NO_SHARE in memory initialization, since it is
deprecated.

Implemented allocator's share virtual method which creates a new
shallow GstVaMemory structure based on the passed one which will be
it's parent.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1626>
---
 sys/va/gstvaallocator.c | 52 +++++++++++++++++++++++++++++++++++------
 1 file changed, 45 insertions(+), 7 deletions(-)

diff --git a/sys/va/gstvaallocator.c b/sys/va/gstvaallocator.c
index 6bebee46e5..2ed728183d 100644
--- a/sys/va/gstvaallocator.c
+++ b/sys/va/gstvaallocator.c
@@ -677,7 +677,7 @@ struct _GstVaAllocator
 typedef struct _GstVaMemory GstVaMemory;
 struct _GstVaMemory
 {
-  GstMemory parent;
+  GstMemory mem;
 
   GstVideoInfo info;
   VASurfaceID surface;
@@ -696,6 +696,8 @@ struct _GstVaMemory
 G_DEFINE_TYPE_WITH_CODE (GstVaAllocator, gst_va_allocator, GST_TYPE_ALLOCATOR,
     _init_debug_category ());
 
+static gboolean _va_unmap (GstVaMemory * mem);
+
 static void
 gst_va_allocator_dispose (GObject * object)
 {
@@ -713,11 +715,20 @@ _va_free (GstAllocator * allocator, GstMemory * mem)
   GstVaAllocator *self = GST_VA_ALLOCATOR (allocator);
   GstVaMemory *va_mem = (GstVaMemory *) mem;
 
-  GST_LOG_OBJECT (self, "Destroying surface %#x", va_mem->surface);
+  if (va_mem->mapped_data) {
+    g_warning (G_STRLOC ":%s: Freeing memory %p still mapped", G_STRFUNC,
+        va_mem);
+    _va_unmap (va_mem);
+  }
+
+  if (va_mem->surface != VA_INVALID_ID && mem->parent == NULL) {
+    GST_LOG_OBJECT (self, "Destroying surface %#x", va_mem->surface);
+    _destroy_surfaces (self->display, &va_mem->surface, 1);
+  }
 
-  _destroy_surfaces (self->display, &va_mem->surface, 1);
   g_mutex_clear (&va_mem->lock);
 
+  GST_DEBUG ("%p: freed", va_mem);
   g_slice_free (GstVaMemory, va_mem);
 }
 
@@ -751,8 +762,8 @@ _reset_mem (GstVaMemory * mem, GstAllocator * allocator, gsize size)
   g_atomic_int_set (&mem->map_count, 0);
   g_mutex_init (&mem->lock);
 
-  gst_memory_init (GST_MEMORY_CAST (mem), GST_MEMORY_FLAG_NO_SHARE, allocator,
-      NULL, size, 0 /* align */ , 0 /* offset */ , size);
+  gst_memory_init (GST_MEMORY_CAST (mem), 0, allocator, NULL, size,
+      0 /* align */ , 0 /* offset */ , size);
 }
 
 static inline gboolean
@@ -913,8 +924,35 @@ _va_unmap (GstVaMemory * mem)
 static GstMemory *
 _va_share (GstMemory * mem, gssize offset, gssize size)
 {
-  /* VA surfaces are opaque structures, which cannot be shared */
-  return NULL;
+  GstVaMemory *vamem = (GstVaMemory *) mem;
+  GstVaMemory *sub;
+  GstMemory *parent;
+  GST_DEBUG ("%p: share %" G_GSSIZE_FORMAT ", %" G_GSIZE_FORMAT, mem, offset,
+      size);
+
+  /* find real parent */
+  if ((parent = vamem->mem.parent) == NULL)
+    parent = (GstMemory *) vamem;
+
+  if (size == -1)
+    size = mem->maxsize - offset;
+
+  sub = g_slice_new (GstVaMemory);
+  /* the shared memory is alwyas readonly */
+  gst_memory_init (GST_MEMORY_CAST (sub), GST_MINI_OBJECT_FLAGS (parent) |
+      GST_MINI_OBJECT_FLAG_LOCK_READONLY, vamem->mem.allocator, parent,
+      vamem->mem.maxsize, vamem->mem.align, vamem->mem.offset + offset, size);
+
+  sub->surface = vamem->surface;
+  sub->surface_format = vamem->surface_format;
+  sub->info = vamem->info;
+
+  _clean_mem (sub);
+
+  g_atomic_int_set (&sub->map_count, 0);
+  g_mutex_init (&sub->lock);
+
+  return GST_MEMORY_CAST (sub);
 }
 
 static void