Mesa (main): drm-shim: Cleanup on device file close

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Module: Mesa
Branch: main
Commit: f3fb1d663277f231f0d429c6bbb784461e26cb09
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f3fb1d663277f231f0d429c6bbb784461e26cb09

Author: Rob Clark <robdclark at chromium.org>
Date:   Sat Apr 30 10:22:31 2022 -0700

drm-shim: Cleanup on device file close

Avoid leaking memory when the device file is closed, dropping bo
references and freeing the shim_fd.

Signed-off-by: Rob Clark <robdclark at chromium.org>
Reviewed-by: Emma Anholt <emma at anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16250>

---

 src/drm-shim/device.c   | 21 ++++++++++++++++++++-
 src/drm-shim/drm_shim.h |  1 +
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/drm-shim/device.c b/src/drm-shim/device.c
index 9ec1f274ea5..6c9c994643b 100644
--- a/src/drm-shim/device.c
+++ b/src/drm-shim/device.c
@@ -117,6 +117,7 @@ drm_shim_file_create(int fd)
    struct shim_fd *shim_fd = calloc(1, sizeof(*shim_fd));
 
    shim_fd->fd = fd;
+   p_atomic_set(&shim_fd->refcount, 1);
    mtx_init(&shim_fd->handle_lock, mtx_plain);
    shim_fd->handles = _mesa_hash_table_create(NULL,
                                               uint_key_hash,
@@ -133,13 +134,31 @@ void drm_shim_fd_register(int fd, struct shim_fd *shim_fd)
 {
    if (!shim_fd)
       shim_fd = drm_shim_file_create(fd);
+   else
+      p_atomic_inc(&shim_fd->refcount);
 
    _mesa_hash_table_insert(shim_device.fd_map, (void *)(uintptr_t)(fd + 1), shim_fd);
 }
 
+static void handle_delete_fxn(struct hash_entry *entry)
+{
+   drm_shim_bo_put(entry->data);
+}
+
 void drm_shim_fd_unregister(int fd)
 {
-   _mesa_hash_table_remove_key(shim_device.fd_map, (void *)(uintptr_t)(fd + 1));
+   struct hash_entry *entry =
+         _mesa_hash_table_search(shim_device.fd_map, (void *)(uintptr_t)(fd + 1));
+   if (!entry)
+      return;
+   struct shim_fd *shim_fd = entry->data;
+   _mesa_hash_table_remove(shim_device.fd_map, entry);
+
+   if (!p_atomic_dec_zero(&shim_fd->refcount))
+      return;
+
+   _mesa_hash_table_destroy(shim_fd->handles, handle_delete_fxn);
+   free(shim_fd);
 }
 
 struct shim_fd *
diff --git a/src/drm-shim/drm_shim.h b/src/drm-shim/drm_shim.h
index 4eda0f15030..7b1bd72e70f 100644
--- a/src/drm-shim/drm_shim.h
+++ b/src/drm-shim/drm_shim.h
@@ -69,6 +69,7 @@ extern struct shim_device shim_device;
 
 struct shim_fd {
    int fd;
+   int refcount;
    mtx_t handle_lock;
    /* mapping from int gem handle to struct shim_bo *. */
    struct hash_table *handles;