minigbm: use drv_array for mappings

Let's start allowing multiple mappings of the same buffer when
different map flags are passed in.

BUG=chromium:764871
TEST=mmap_test -g on Kevin, gbmtest

Change-Id: I4eb0b6f4c3572a92001696c2720d5a5f7d9d73a4
Reviewed-on: https://chromium-review.googlesource.com/758146
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Joe Kniss <djmk@google.com>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>

3 files changed, 56 insertions, 40 deletions

diff --git a/drv.c b/drv.c
index cb54a93..50d3401 100644
--- a/drv.c
+++ b/drv.c
@@ -132,8 +132,8 @@ struct driver *drv_create(int fd)
 	if (!drv->buffer_table)
 		goto free_lock;
 
-	drv->map_table = drmHashCreate();
-	if (!drv->map_table)
+	drv->mappings = drv_array_init(sizeof(struct mapping));
+	if (!drv->mappings)
 		goto free_buffer_table;
 
 	/* Start with a power of 2 number of allocations. */
@@ -142,20 +142,20 @@ struct driver *drv_create(int fd)
 
 	drv->combos.data = calloc(drv->combos.allocations, sizeof(struct combination));
 	if (!drv->combos.data)
-		goto free_map_table;
+		goto free_mappings;
 
 	if (drv->backend->init) {
 		ret = drv->backend->init(drv);
 		if (ret) {
 			free(drv->combos.data);
-			goto free_map_table;
+			goto free_mappings;
 		}
 	}
 
 	return drv;
 
-free_map_table:
-	drmHashDestroy(drv->map_table);
+free_mappings:
+	drv_array_destroy(drv->mappings);
 free_buffer_table:
 	drmHashDestroy(drv->buffer_table);
 free_lock:
@@ -173,7 +173,7 @@ void drv_destroy(struct driver *drv)
 		drv->backend->close(drv);
 
 	drmHashDestroy(drv->buffer_table);
-	drmHashDestroy(drv->map_table);
+	drv_array_destroy(drv->mappings);
 
 	free(drv->combos.data);
 
@@ -385,10 +385,10 @@ destroy_bo:
 void *drv_bo_map(struct bo *bo, uint32_t x, uint32_t y, uint32_t width, uint32_t height,
 		 uint32_t map_flags, struct mapping **map_data, size_t plane)
 {
-	void *ptr;
+	uint32_t i;
 	uint8_t *addr;
 	size_t offset;
-	struct mapping *mapping;
+	struct mapping mapping;
 
 	assert(width > 0);
 	assert(height > 0);
@@ -398,39 +398,40 @@ void *drv_bo_map(struct bo *bo, uint32_t x, uint32_t y, uint32_t width, uint32_t
 	/* No CPU access for protected buffers. */
 	assert(!(bo->use_flags & BO_USE_PROTECTED));
 
+	memset(&mapping, 0, sizeof(mapping));
 	pthread_mutex_lock(&bo->drv->driver_lock);
 
-	if (!drmHashLookup(bo->drv->map_table, bo->handles[plane].u32, &ptr)) {
-		mapping = (struct mapping *)ptr;
-		/* TODO(gsingh): support mapping same buffer with different flags. */
-		assert(mapping->vma->map_flags == map_flags);
-		mapping->vma->refcount++;
+	for (i = 0; i < drv_array_size(bo->drv->mappings); i++) {
+		struct mapping *prior = (struct mapping *)drv_array_at_idx(bo->drv->mappings, i);
+		if (prior->vma->handle != bo->handles[plane].u32 ||
+		    prior->vma->map_flags != map_flags)
+			continue;
+
+		prior->vma->refcount++;
+		mapping.vma = prior->vma;
 		goto success;
 	}
 
-	mapping = calloc(1, sizeof(*mapping));
-	mapping->vma = calloc(1, sizeof(*mapping->vma));
-	addr = bo->drv->backend->bo_map(bo, mapping, plane, map_flags);
+	mapping.vma = calloc(1, sizeof(*mapping.vma));
+	addr = bo->drv->backend->bo_map(bo, &mapping, plane, map_flags);
 	if (addr == MAP_FAILED) {
 		*map_data = NULL;
-		free(mapping->vma);
-		free(mapping);
+		free(mapping.vma);
 		pthread_mutex_unlock(&bo->drv->driver_lock);
 		return MAP_FAILED;
 	}
 
-	mapping->vma->refcount = 1;
-	mapping->vma->addr = addr;
-	mapping->vma->handle = bo->handles[plane].u32;
-	mapping->vma->map_flags = map_flags;
-	drmHashInsert(bo->drv->map_table, bo->handles[plane].u32, (void *)mapping);
+	mapping.vma->refcount = 1;
+	mapping.vma->addr = addr;
+	mapping.vma->handle = bo->handles[plane].u32;
+	mapping.vma->map_flags = map_flags;
 
 success:
-	drv_bo_invalidate(bo, mapping);
-	*map_data = mapping;
+	drv_bo_invalidate(bo, &mapping);
+	*map_data = drv_array_append(bo->drv->mappings, &mapping);
 	offset = drv_bo_get_plane_stride(bo, plane) * y;
 	offset += drv_stride_from_format(bo->format, x, plane);
-	addr = (uint8_t *)mapping->vma->addr;
+	addr = (uint8_t *)mapping.vma->addr;
 	addr += drv_bo_get_plane_offset(bo, plane) + offset;
 	pthread_mutex_unlock(&bo->drv->driver_lock);
 
@@ -439,6 +440,7 @@ success:
 
 int drv_bo_unmap(struct bo *bo, struct mapping *mapping)
 {
+	uint32_t i;
 	int ret = drv_bo_flush(bo, mapping);
 	if (ret)
 		return ret;
@@ -447,9 +449,14 @@ int drv_bo_unmap(struct bo *bo, struct mapping *mapping)
 
 	if (!--mapping->vma->refcount) {
 		ret = bo->drv->backend->bo_unmap(bo, mapping);
-		drmHashDelete(bo->drv->map_table, mapping->vma->handle);
 		free(mapping->vma);
-		free(mapping);
+	}
+
+	for (i = 0; i < drv_array_size(bo->drv->mappings); i++) {
+		if (mapping == (struct mapping *)drv_array_at_idx(bo->drv->mappings, i)) {
+			drv_array_remove(bo->drv->mappings, i);
+			break;
+		}
 	}
 
 	pthread_mutex_unlock(&bo->drv->driver_lock);
diff --git a/drv_priv.h b/drv_priv.h
index e5b9d55..dceeeb7 100644
--- a/drv_priv.h
+++ b/drv_priv.h
@@ -60,7 +60,7 @@ struct driver {
 	const struct backend *backend;
 	void *priv;
 	void *buffer_table;
-	void *map_table;
+	struct drv_array *mappings;
 	struct combinations combos;
 	pthread_mutex_t driver_lock;
 };
diff --git a/helpers.c b/helpers.c
index 555fb85..d861b9c 100644
--- a/helpers.c
+++ b/helpers.c
@@ -340,27 +340,36 @@ int drv_bo_munmap(struct bo *bo, struct mapping *mapping)
 int drv_mapping_destroy(struct bo *bo)
 {
 	int ret;
-	void *ptr;
 	size_t plane;
 	struct mapping *mapping;
+	uint32_t idx;
 
 	/*
 	 * This function is called right before the buffer is destroyed. It will free any mappings
 	 * associated with the buffer.
 	 */
 
+	idx = 0;
 	for (plane = 0; plane < bo->num_planes; plane++) {
-		if (!drmHashLookup(bo->drv->map_table, bo->handles[plane].u32, &ptr)) {
-			mapping = (struct mapping *)ptr;
-			ret = bo->drv->backend->bo_unmap(bo, mapping);
-			if (ret) {
-				fprintf(stderr, "drv: munmap failed");
-				return ret;
+		while (idx < drv_array_size(bo->drv->mappings)) {
+			mapping = (struct mapping *)drv_array_at_idx(bo->drv->mappings, idx);
+			if (mapping->vma->handle != bo->handles[plane].u32) {
+				idx++;
+				continue;
 			}
 
-			drmHashDelete(bo->drv->map_table, mapping->vma->handle);
-			free(mapping->vma);
-			free(mapping);
+			if (!--mapping->vma->refcount) {
+				ret = bo->drv->backend->bo_unmap(bo, mapping);
+				if (ret) {
+					fprintf(stderr, "drv: munmap failed");
+					return ret;
+				}
+
+				free(mapping->vma);
+			}
+
+			/* This shrinks and shifts the array, so don't increment idx. */
+			drv_array_remove(bo->drv->mappings, idx);
 		}
 	}