When using Mesa and LibVA in the same process, one would like to be
able bind buffers from the output of the decoder to a GL texture
through an EGLImage.
LibVA can reuse buffers allocated by Gbm through a file descriptor. It
will then wrap it into a drm_intel_bo with
drm_intel_bo_gem_create_from_prime().
Given both libraries are using libdrm to allocate and use buffer
objects, there is a need to have the buffer objects properly
refcounted. That is possible if both API use the same drm_intel_bo
objects, but that also requires that both API use the same
drm_intel_bufmgr object.
This patch modifies drm_intel_bufmgr_gem_init() so given a file
descriptor, it will look for an already existing drm_intel_bufmgr
using the same file descriptor and return that object.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
---
intel/intel_bufmgr_gem.c | 100 +++++++++++++++++++++++++++++++++++++++++------
1 file changed, 88 insertions(+), 12 deletions(-)
diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index 0e1cb0d..125c81c 100644
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -94,6 +94,8 @@ struct drm_intel_gem_bo_bucket {
typedef struct _drm_intel_bufmgr_gem {
drm_intel_bufmgr bufmgr;
+ atomic_t refcount;
+
int fd;
int max_relocs;
@@ -3186,6 +3188,85 @@ drm_intel_bufmgr_gem_set_aub_annotations(drm_intel_bo *bo,
bo_gem->aub_annotation_count = count;
}
+static pthread_mutex_t bufmgr_list_mutex = PTHREAD_MUTEX_INITIALIZER;
+static drm_intel_bufmgr_gem **bufmgr_list = NULL;
+static unsigned bufmgr_list_size = 0, bufmgr_list_nb;
+
+static drm_intel_bufmgr_gem *
+drm_intel_bufmgr_gem_find_or_create_for_fd(int fd, int *found)
+{
+ drm_intel_bufmgr_gem *bufmgr_gem;
+
+ assert(pthread_mutex_lock(&bufmgr_list_mutex) == 0);
+
+ if (bufmgr_list == NULL) {
+ bufmgr_list_size = 2;
+ bufmgr_list = calloc(bufmgr_list_size, sizeof(drm_intel_bufmgr_gem *));
+ } else {
+ unsigned i;
+ for (i = 0; i < bufmgr_list_nb; i++) {
+ bufmgr_gem = bufmgr_list[i];
+ if (bufmgr_gem->fd == fd) {
+ atomic_inc(&bufmgr_gem->refcount);
+ *found = 1;
+ goto exit;
+ }
+ }
+ }
+
+ bufmgr_gem = calloc(1, sizeof(*bufmgr_gem));
+ if (bufmgr_gem == NULL)
+ goto exit;
+
+ bufmgr_gem->fd = fd;
+ atomic_set(&bufmgr_gem->refcount, 1);
+
+ assert(pthread_mutex_init(&bufmgr_gem->lock, NULL) == 0);
+
+ if (bufmgr_list_nb >= bufmgr_list_size) {
+ bufmgr_list_size *= 2;
+ bufmgr_list = realloc(bufmgr_list, bufmgr_list_size);
+ assert(bufmgr_list != NULL);
+ }
+ bufmgr_list[bufmgr_list_nb] = bufmgr_gem;
+ bufmgr_list_nb++;
+
+ pthread_mutex_lock(&bufmgr_gem->lock);
+
+ *found = 0;
+
+exit:
+ pthread_mutex_unlock(&bufmgr_list_mutex);
+
+ return bufmgr_gem;
+}
+
+static void
+drm_intel_bufmgr_gem_unref (drm_intel_bufmgr *bufmgr)
+{
+ drm_intel_bufmgr_gem *bufmgr_gem = (drm_intel_bufmgr_gem *)bufmgr;
+
+ if (atomic_dec_and_test(&bufmgr_gem->refcount)) {
+ unsigned i, compact_start = bufmgr_list_nb;
+
+ assert(pthread_mutex_lock(&bufmgr_list_mutex) == 0);
+
+ for (i = 0; i < bufmgr_list_nb; i++) {
+ if (bufmgr_list[i] == bufmgr_gem) {
+ compact_start = i;
+ bufmgr_list_nb--;
+ break;
+ }
+ }
+ for (i = compact_start; i < bufmgr_list_nb; i++)
+ bufmgr_list[i] = bufmgr_list[i + 1];
+
+ pthread_mutex_unlock(&bufmgr_list_mutex);
+
+ drm_intel_bufmgr_gem_destroy(bufmgr);
+ }
+}
+
/**
* Initializes the GEM buffer manager, which uses the kernel to allocate, map,
* and manage map buffer objections.
@@ -3201,16 +3282,9 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
int ret, tmp;
bool exec2 = false;
- bufmgr_gem = calloc(1, sizeof(*bufmgr_gem));
- if (bufmgr_gem == NULL)
- return NULL;
-
- bufmgr_gem->fd = fd;
-
- if (pthread_mutex_init(&bufmgr_gem->lock, NULL) != 0) {
- free(bufmgr_gem);
- return NULL;
- }
+ bufmgr_gem = drm_intel_bufmgr_gem_find_or_create_for_fd(fd, &ret);
+ if (bufmgr_gem && ret)
+ return &bufmgr_gem->bufmgr;
ret = drmIoctl(bufmgr_gem->fd,
DRM_IOCTL_I915_GEM_GET_APERTURE,
@@ -3245,7 +3319,7 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
else if (IS_GEN8(bufmgr_gem->pci_device))
bufmgr_gem->gen = 8;
else {
- free(bufmgr_gem);
+ drm_intel_bufmgr_gem_unref(&bufmgr_gem->bufmgr);
return NULL;
}
@@ -3357,7 +3431,7 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
bufmgr_gem->bufmgr.bo_exec = drm_intel_gem_bo_exec;
bufmgr_gem->bufmgr.bo_busy = drm_intel_gem_bo_busy;
bufmgr_gem->bufmgr.bo_madvise = drm_intel_gem_bo_madvise;
- bufmgr_gem->bufmgr.destroy = drm_intel_bufmgr_gem_destroy;
+ bufmgr_gem->bufmgr.destroy = drm_intel_bufmgr_gem_unref;
bufmgr_gem->bufmgr.debug = 0;
bufmgr_gem->bufmgr.check_aperture_space =
drm_intel_gem_check_aperture_space;
@@ -3373,5 +3447,7 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
DRMINITLISTHEAD(&bufmgr_gem->vma_cache);
bufmgr_gem->vma_max = -1; /* unlimited by default */
+ pthread_mutex_unlock(&bufmgr_gem->lock);
+
return &bufmgr_gem->bufmgr;
}
--
2.0.1
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