[Mesa-dev] [PATCH 20/23] anv: Add flag IGNORE_SIZE_PARAM for anv_bo_cache_import()

[Chad Versace]

If ANV_BO_CACHE_IMPORT_IGNORE_SIZE_PARAM is set, then the function
ignores the 'size' parameter. Instead, on a cache hit, it uses the cached bo's
size; on a cache miss, it queries the fd's size.

This prepares for implementing VK_ANDROID_native_buffer, in which the
API provides no explicit size for the gralloc buffer. Instead, we must
query the dma_buf's size with lseek.
---
 src/intel/vulkan/anv_allocator.c | 9 ++++++++-
 src/intel/vulkan/anv_private.h   | 6 ++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/intel/vulkan/anv_allocator.c b/src/intel/vulkan/anv_allocator.c
index 28d00f4d0b2..af5d565b70a 100644
--- a/src/intel/vulkan/anv_allocator.c
+++ b/src/intel/vulkan/anv_allocator.c
@@ -1277,7 +1277,8 @@ anv_bo_cache_import(struct anv_device *device,
    pthread_mutex_lock(&cache->mutex);
 
    /* The kernel is going to give us whole pages anyway */
-   size = align_u64(size, 4096);
+   if (!(flags & ANV_BO_CACHE_IMPORT_IGNORE_SIZE_PARAM))
+      size = align_u64(size, 4096);
 
    uint32_t gem_handle = anv_gem_fd_to_handle(device, fd);
    if (!gem_handle) {
@@ -1287,6 +1288,9 @@ anv_bo_cache_import(struct anv_device *device,
 
    struct anv_cached_bo *bo = anv_bo_cache_lookup_locked(cache, gem_handle);
    if (bo) {
+      if (flags & ANV_BO_CACHE_IMPORT_IGNORE_SIZE_PARAM)
+         size = bo->bo.size;
+
       if (bo->bo.size != size) {
          pthread_mutex_unlock(&cache->mutex);
          return vk_error(VK_ERROR_INVALID_EXTERNAL_HANDLE_KHR);
@@ -1302,6 +1306,9 @@ anv_bo_cache_import(struct anv_device *device,
        * this sort of attack but only if it can trust the buffer size.
        */
       off_t import_size = lseek(fd, 0, SEEK_END);
+      if (flags & ANV_BO_CACHE_IMPORT_IGNORE_SIZE_PARAM)
+         size = import_size;
+
       if (import_size == (off_t)-1 || import_size != size) {
          anv_gem_close(device, gem_handle);
          pthread_mutex_unlock(&cache->mutex);
diff --git a/src/intel/vulkan/anv_private.h b/src/intel/vulkan/anv_private.h
index 014848fcef2..9c73939feb0 100644
--- a/src/intel/vulkan/anv_private.h
+++ b/src/intel/vulkan/anv_private.h
@@ -589,6 +589,12 @@ struct anv_bo_cache {
 enum anv_bo_cache_import_bits {
    /** Do not close the fd after import. */
    ANV_BO_CACHE_IMPORT_NO_CLOSE_FD = (1 << 0),
+
+   /**
+    * Ignore the anv_bo_cache_import::size parameter. Instead, on a cache hit,
+    * use the cached bo's size; on a cache miss, query the fd's size.
+    */
+   ANV_BO_CACHE_IMPORT_IGNORE_SIZE_PARAM = (1 << 1),
 };
 typedef uint32_t anv_bo_cache_import_flags_t;
 
-- 
2.13.5