[Mesa-dev] [RFC 5/7] nouveau: remove screen ref counting

[Rob Herring]

Now that the pipe-loader is reference counting the screen creation, it
is unnecessary to do in it the winsys/driver.

Signed-off-by: Rob Herring <robh at kernel.org>
Cc: Alexandre Courbot <acourbot at nvidia.com>
---
 src/gallium/drivers/nouveau/nouveau_screen.h       |  2 -
 .../winsys/nouveau/drm/nouveau_drm_winsys.c        | 84 +---------------------
 2 files changed, 2 insertions(+), 84 deletions(-)

diff --git a/src/gallium/drivers/nouveau/nouveau_screen.h b/src/gallium/drivers/nouveau/nouveau_screen.h
index 28c4760..3e17472 100644
--- a/src/gallium/drivers/nouveau/nouveau_screen.h
+++ b/src/gallium/drivers/nouveau/nouveau_screen.h
@@ -23,8 +23,6 @@ struct nouveau_screen {
    struct nouveau_client *client;
    struct nouveau_pushbuf *pushbuf;
 
-   int refcount;
-
    unsigned vidmem_bindings; /* PIPE_BIND_* where VRAM placement is desired */
    unsigned sysmem_bindings; /* PIPE_BIND_* where GART placement is desired */
    unsigned lowmem_bindings; /* PIPE_BIND_* that require an address < 4 GiB */
diff --git a/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c b/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
index 598ffcb..179d25a 100644
--- a/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
+++ b/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
@@ -1,12 +1,9 @@
-#include <sys/stat.h>
 #include <unistd.h>
 #include "pipe/p_context.h"
 #include "pipe/p_state.h"
 #include "util/u_format.h"
 #include "util/u_memory.h"
 #include "util/u_inlines.h"
-#include "util/u_hash_table.h"
-#include "os/os_thread.h"
 
 #include "nouveau_drm_public.h"
 
@@ -16,47 +13,6 @@
 #include <nvif/class.h>
 #include <nvif/cl0080.h>
 
-static struct util_hash_table *fd_tab = NULL;
-
-pipe_static_mutex(nouveau_screen_mutex);
-
-bool nouveau_drm_screen_unref(struct nouveau_screen *screen)
-{
-	int ret;
-	if (screen->refcount == -1)
-		return true;
-
-	pipe_mutex_lock(nouveau_screen_mutex);
-	ret = --screen->refcount;
-	assert(ret >= 0);
-	if (ret == 0)
-		util_hash_table_remove(fd_tab, intptr_to_pointer(screen->drm->fd));
-	pipe_mutex_unlock(nouveau_screen_mutex);
-	return ret == 0;
-}
-
-static unsigned hash_fd(void *key)
-{
-    int fd = pointer_to_intptr(key);
-    struct stat stat;
-    fstat(fd, &stat);
-
-    return stat.st_dev ^ stat.st_ino ^ stat.st_rdev;
-}
-
-static int compare_fd(void *key1, void *key2)
-{
-    int fd1 = pointer_to_intptr(key1);
-    int fd2 = pointer_to_intptr(key2);
-    struct stat stat1, stat2;
-    fstat(fd1, &stat1);
-    fstat(fd2, &stat2);
-
-    return stat1.st_dev != stat2.st_dev ||
-           stat1.st_ino != stat2.st_ino ||
-           stat1.st_rdev != stat2.st_rdev;
-}
-
 PUBLIC struct pipe_screen *
 nouveau_drm_screen_create(int fd)
 {
@@ -64,36 +20,9 @@ nouveau_drm_screen_create(int fd)
 	struct nouveau_device *dev = NULL;
 	struct nouveau_screen *(*init)(struct nouveau_device *);
 	struct nouveau_screen *screen = NULL;
-	int ret, dupfd;
-
-	pipe_mutex_lock(nouveau_screen_mutex);
-	if (!fd_tab) {
-		fd_tab = util_hash_table_create(hash_fd, compare_fd);
-		if (!fd_tab) {
-			pipe_mutex_unlock(nouveau_screen_mutex);
-			return NULL;
-		}
-	}
-
-	screen = util_hash_table_get(fd_tab, intptr_to_pointer(fd));
-	if (screen) {
-		screen->refcount++;
-		pipe_mutex_unlock(nouveau_screen_mutex);
-		return &screen->base;
-	}
-
-	/* Since the screen re-use is based on the device node and not the fd,
-	 * create a copy of the fd to be owned by the device. Otherwise a
-	 * scenario could occur where two screens are created, and the first
-	 * one is shut down, along with the fd being closed. The second
-	 * (identical) screen would now have a reference to the closed fd. We
-	 * avoid this by duplicating the original fd. Note that
-	 * nouveau_device_wrap does not close the fd in case of a device
-	 * creation error.
-	 */
-	dupfd = dup(fd);
+	int ret;
 
-	ret = nouveau_drm_new(dupfd, &drm);
+	ret = nouveau_drm_new(fd, &drm);
 	if (ret)
 		goto err;
 
@@ -135,13 +64,6 @@ nouveau_drm_screen_create(int fd)
 	if (!screen || !screen->base.context_create)
 		goto err;
 
-	/* Use dupfd in hash table, to avoid errors if the original fd gets
-	 * closed by its owner. The hash key needs to live at least as long as
-	 * the screen.
-	 */
-	util_hash_table_set(fd_tab, intptr_to_pointer(dupfd), screen);
-	screen->refcount = 1;
-	pipe_mutex_unlock(nouveau_screen_mutex);
 	return &screen->base;
 
 err:
@@ -150,8 +72,6 @@ err:
 	} else {
 		nouveau_device_del(&dev);
 		nouveau_drm_del(&drm);
-		close(dupfd);
 	}
-	pipe_mutex_unlock(nouveau_screen_mutex);
 	return NULL;
 }
-- 
2.7.4