[Mesa-dev] [PATCH 05/11] nouveau: use common screen ref counting
Ilia Mirkin
imirkin at alum.mit.edu
Fri Jun 24 00:01:15 UTC 2016
As before, you need to keep the dupfd. There's even a long comment there to
explain why.
On Jun 23, 2016 7:58 PM, "Rob Herring" <robh at kernel.org> wrote:
> Use the common pipe_screen ref counting and fd hashing functions. The
> mutex can be dropped as the pipe loader protects the create_screen()
> calls.
>
> Signed-off-by: Rob Herring <robh at kernel.org>
> Cc: Alexandre Courbot <acourbot at nvidia.com>
> ---
> src/gallium/drivers/nouveau/nouveau_screen.c | 6 --
> src/gallium/drivers/nouveau/nouveau_screen.h | 4 -
> src/gallium/drivers/nouveau/nv30/nv30_screen.c | 3 -
> src/gallium/drivers/nouveau/nv50/nv50_screen.c | 3 -
> src/gallium/drivers/nouveau/nvc0/nvc0_screen.c | 3 -
> .../winsys/nouveau/drm/nouveau_drm_winsys.c | 89
> ++--------------------
> 6 files changed, 7 insertions(+), 101 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/nouveau_screen.c
> b/src/gallium/drivers/nouveau/nouveau_screen.c
> index 2c421cc..41d4bef 100644
> --- a/src/gallium/drivers/nouveau/nouveau_screen.c
> +++ b/src/gallium/drivers/nouveau/nouveau_screen.c
> @@ -159,12 +159,6 @@ nouveau_screen_init(struct nouveau_screen *screen,
> struct nouveau_device *dev)
> screen->drm = nouveau_drm(&dev->object);
> screen->device = dev;
>
> - /*
> - * this is initialized to 1 in nouveau_drm_screen_create after screen
> - * is fully constructed and added to the global screen list.
> - */
> - screen->refcount = -1;
> -
> if (dev->chipset < 0xc0) {
> data = &nv04_data;
> size = sizeof(nv04_data);
> diff --git a/src/gallium/drivers/nouveau/nouveau_screen.h
> b/src/gallium/drivers/nouveau/nouveau_screen.h
> index 28c4760..55156c3 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 */
> @@ -119,8 +117,6 @@ nouveau_screen(struct pipe_screen *pscreen)
> return (struct nouveau_screen *)pscreen;
> }
>
> -bool nouveau_drm_screen_unref(struct nouveau_screen *screen);
> -
> bool
> nouveau_screen_bo_get_handle(struct pipe_screen *pscreen,
> struct nouveau_bo *bo,
> diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
> b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
> index de798cf..08194fd 100644
> --- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
> +++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
> @@ -406,9 +406,6 @@ nv30_screen_destroy(struct pipe_screen *pscreen)
> {
> struct nv30_screen *screen = nv30_screen(pscreen);
>
> - if (!nouveau_drm_screen_unref(&screen->base))
> - return;
> -
> if (screen->base.fence.current) {
> struct nouveau_fence *current = NULL;
>
> diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
> b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
> index 03f4591..1654d0e 100644
> --- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
> +++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
> @@ -425,9 +425,6 @@ nv50_screen_destroy(struct pipe_screen *pscreen)
> {
> struct nv50_screen *screen = nv50_screen(pscreen);
>
> - if (!nouveau_drm_screen_unref(&screen->base))
> - return;
> -
> if (screen->base.fence.current) {
> struct nouveau_fence *current = NULL;
>
> diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
> b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
> index b9437b2..712293a 100644
> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
> @@ -481,9 +481,6 @@ nvc0_screen_destroy(struct pipe_screen *pscreen)
> {
> struct nvc0_screen *screen = nvc0_screen(pscreen);
>
> - if (!nouveau_drm_screen_unref(&screen->base))
> - return;
> -
> if (screen->base.fence.current) {
> struct nouveau_fence *current = NULL;
>
> diff --git a/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
> b/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
> index 598ffcb..b5f4247 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 "util/u_screen.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 +20,13 @@ 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;
> - }
> + struct pipe_screen *pscreen = pipe_screen_reference(fd);
> + int ret;
>
> - /* 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);
> + if (pscreen)
> + return pscreen;
>
> - ret = nouveau_drm_new(dupfd, &drm);
> + ret = nouveau_drm_new(fd, &drm);
> if (ret)
> goto err;
>
> @@ -135,13 +68,7 @@ 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);
> + pipe_screen_reference_init(&screen->base, fd);
> return &screen->base;
>
> err:
> @@ -150,8 +77,6 @@ err:
> } else {
> nouveau_device_del(&dev);
> nouveau_drm_del(&drm);
> - close(dupfd);
> }
> - pipe_mutex_unlock(nouveau_screen_mutex);
> return NULL;
> }
> --
> 2.9.0
>
>
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