From 07a0b6347208914f6b1ebf7e09bc54587dd6d49a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADctor=20Manuel=20J=C3=A1quez=20Leal?=
 <vjaquez@igalia.com>
Date: Sat, 3 Apr 2021 14:16:22 +0200
Subject: [PATCH] va: allocator: Implement mem_copy for VA memory.

Implementation of mem_copy() virtual method for GstVaAllocator.

It's a deep copy where a new VA memory is popped out from the pool or,
if pool is empty, a new memory is allocated. The original memory is
mapped to read, and if its VAImage is not derived and size to copy is
the whole surface, the mapped VAImage of the original memory is put in
the new memory. Otherwise a slow memcpy is done between both memories.

Fixes: #1568
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2136>
---
 sys/va/gstvaallocator.c | 68 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/sys/va/gstvaallocator.c b/sys/va/gstvaallocator.c
index 7b50cacf56..7c162946b1 100644
--- a/sys/va/gstvaallocator.c
+++ b/sys/va/gstvaallocator.c
@@ -1218,7 +1218,7 @@ _va_map_unlocked (GstVaMemory * mem, GstMapFlags flags)
   g_return_val_if_fail (GST_IS_VA_ALLOCATOR (allocator), NULL);
 
   if (g_atomic_int_get (&mem->map_count) > 0) {
-    if (mem->prev_mapflags != flags || !mem->mapped_data)
+    if (!(mem->prev_mapflags & flags) || !mem->mapped_data)
       return NULL;
     else
       goto success;
@@ -1339,6 +1339,7 @@ _va_share (GstMemory * mem, gssize offset, gssize size)
   GstVaMemory *vamem = (GstVaMemory *) mem;
   GstVaMemory *sub;
   GstMemory *parent;
+
   GST_DEBUG ("%p: share %" G_GSSIZE_FORMAT ", %" G_GSIZE_FORMAT, mem, offset,
       size);
 
@@ -1350,6 +1351,7 @@ _va_share (GstMemory * mem, gssize offset, gssize size)
     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,
@@ -1366,6 +1368,69 @@ _va_share (GstMemory * mem, gssize offset, gssize size)
   return GST_MEMORY_CAST (sub);
 }
 
+/* XXX(victor): deep copy implementation. A further optimization can
+ * be done with vaCopy() from libva 2.12 */
+static GstMemory *
+_va_copy (GstMemory * mem, gssize offset, gssize size)
+{
+  GstMemory *copy;
+  GstMapInfo sinfo, dinfo;
+  GstVaAllocator *va_allocator = GST_VA_ALLOCATOR (mem->allocator);
+
+  GST_DEBUG ("%p: copy %" G_GSSIZE_FORMAT ", %" G_GSIZE_FORMAT, mem, offset,
+      size);
+
+  {
+    GST_VA_MEMORY_POOL_LOCK (&va_allocator->pool);
+    copy = gst_va_memory_pool_pop (&va_allocator->pool);
+    GST_VA_MEMORY_POOL_UNLOCK (&va_allocator->pool);
+
+    if (!copy) {
+      copy = gst_va_allocator_alloc (mem->allocator);
+      if (!copy) {
+        GST_WARNING ("failed to allocate new memory");
+        gst_memory_unmap (mem, &sinfo);
+        return NULL;
+      }
+    } else {
+      gst_object_ref (mem->allocator);
+    }
+  }
+
+  if (!gst_memory_map (mem, &sinfo, GST_MAP_READ))
+    return NULL;
+
+  if (size == -1)
+    size = sinfo.size > offset ? sinfo.size - offset : 0;
+
+  if (offset == 0 && size == sinfo.size) {
+    GstVaMemory *va_mem = (GstVaMemory *) mem;
+    GstVaMemory *va_copy = (GstVaMemory *) copy;
+
+    if (!va_mem->is_derived) {
+      if (_put_image (va_allocator->display, va_copy->surface, &va_mem->image)) {
+        GST_LOG ("shallow copy of %#x to %#x", va_mem->surface,
+            va_copy->surface);
+        gst_memory_unmap (mem, &sinfo);
+        return copy;
+      }
+    }
+  }
+
+  if (!gst_memory_map (copy, &dinfo, GST_MAP_WRITE)) {
+    GST_WARNING ("could not write map memory %p", copy);
+    gst_allocator_free (mem->allocator, copy);
+    gst_memory_unmap (mem, &sinfo);
+    return NULL;
+  }
+
+  memcpy (dinfo.data, sinfo.data + offset, size);
+  gst_memory_unmap (copy, &dinfo);
+  gst_memory_unmap (mem, &sinfo);
+
+  return copy;
+}
+
 static void
 gst_va_allocator_init (GstVaAllocator * self)
 {
@@ -1375,6 +1440,7 @@ gst_va_allocator_init (GstVaAllocator * self)
   allocator->mem_map = (GstMemoryMapFunction) _va_map;
   allocator->mem_unmap = (GstMemoryUnmapFunction) _va_unmap;
   allocator->mem_share = _va_share;
+  allocator->mem_copy = _va_copy;
 
   gst_va_memory_pool_init (&self->pool);