intel: Track known prime buffers for re-use

If the application sends us a file descriptor pointing at a prime
buffer that we've already got, we have to re-use the same bo_gem
structure or chaos will result.

Track the set of all known prime objects and look to see if the kernel
has returned one of those for a new file descriptor.

Also checks for prime buffers in the flink case.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index c11ed45..48ff62e 100644 (file)
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -149,6 +149,8 @@ struct _drm_intel_bo_gem {
 
        /**
         * Kenel-assigned global name for this object
+         *
+         * List contains both flink named and prime fd'd objects
         */
        unsigned int global_name;
        drmMMListHead name_list;
@@ -862,10 +864,6 @@ drm_intel_bo_gem_create_from_name(drm_intel_bufmgr *bufmgr,
                }
        }
 
-       bo_gem = calloc(1, sizeof(*bo_gem));
-       if (!bo_gem)
-               return NULL;
-
        VG_CLEAR(open_arg);
        open_arg.name = handle;
        ret = drmIoctl(bufmgr_gem->fd,
@@ -874,9 +872,26 @@ drm_intel_bo_gem_create_from_name(drm_intel_bufmgr *bufmgr,
        if (ret != 0) {
                DBG("Couldn't reference %s handle 0x%08x: %s\n",
                    name, handle, strerror(errno));
-               free(bo_gem);
                return NULL;
        }
+        /* Now see if someone has used a prime handle to get this
+         * object from the kernel before by looking through the list
+         * again for a matching gem_handle
+         */
+       for (list = bufmgr_gem->named.next;
+            list != &bufmgr_gem->named;
+            list = list->next) {
+               bo_gem = DRMLISTENTRY(drm_intel_bo_gem, list, name_list);
+               if (bo_gem->gem_handle == open_arg.handle) {
+                       drm_intel_gem_bo_reference(&bo_gem->bo);
+                       return &bo_gem->bo;
+               }
+       }
+
+       bo_gem = calloc(1, sizeof(*bo_gem));
+       if (!bo_gem)
+               return NULL;
+
        bo_gem->bo.size = open_arg.size;
        bo_gem->bo.offset = 0;
        bo_gem->bo.virtual = NULL;
@@ -2451,8 +2466,25 @@ drm_intel_bo_gem_create_from_prime(drm_intel_bufmgr *bufmgr, int prime_fd, int s
        uint32_t handle;
        drm_intel_bo_gem *bo_gem;
        struct drm_i915_gem_get_tiling get_tiling;
+       drmMMListHead *list;
 
        ret = drmPrimeFDToHandle(bufmgr_gem->fd, prime_fd, &handle);
+
+       /*
+        * See if the kernel has already returned this buffer to us. Just as
+        * for named buffers, we must not create two bo's pointing at the same
+        * kernel object
+        */
+       for (list = bufmgr_gem->named.next;
+            list != &bufmgr_gem->named;
+            list = list->next) {
+               bo_gem = DRMLISTENTRY(drm_intel_bo_gem, list, name_list);
+               if (bo_gem->gem_handle == handle) {
+                       drm_intel_gem_bo_reference(&bo_gem->bo);
+                       return &bo_gem->bo;
+               }
+       }
+
        if (ret) {
          fprintf(stderr,"ret is %d %d\n", ret, errno);
                return NULL;
@@ -2487,8 +2519,8 @@ drm_intel_bo_gem_create_from_prime(drm_intel_bufmgr *bufmgr, int prime_fd, int s
        bo_gem->has_error = false;
        bo_gem->reusable = false;
 
-       DRMINITLISTHEAD(&bo_gem->name_list);
        DRMINITLISTHEAD(&bo_gem->vma_list);
+       DRMLISTADDTAIL(&bo_gem->name_list, &bufmgr_gem->named);
 
        VG_CLEAR(get_tiling);
        get_tiling.handle = bo_gem->gem_handle;
@@ -2513,6 +2545,9 @@ drm_intel_bo_gem_export_to_prime(drm_intel_bo *bo, int *prime_fd)
        drm_intel_bufmgr_gem *bufmgr_gem = (drm_intel_bufmgr_gem *) bo->bufmgr;
        drm_intel_bo_gem *bo_gem = (drm_intel_bo_gem *) bo;
 
+        if (DRMLISTEMPTY(&bo_gem->name_list))
+                DRMLISTADDTAIL(&bo_gem->name_list, &bufmgr_gem->named);
+
        if (drmPrimeHandleToFD(bufmgr_gem->fd, bo_gem->gem_handle,
                               DRM_CLOEXEC, prime_fd) != 0)
                return -errno;
@@ -2542,7 +2577,8 @@ drm_intel_gem_bo_flink(drm_intel_bo *bo, uint32_t * name)
                bo_gem->global_name = flink.name;
                bo_gem->reusable = false;
 
-               DRMLISTADDTAIL(&bo_gem->name_list, &bufmgr_gem->named);
+                if (DRMLISTEMPTY(&bo_gem->name_list))
+                        DRMLISTADDTAIL(&bo_gem->name_list, &bufmgr_gem->named);
        }
 
        *name = bo_gem->global_name;