[Mesa-dev] [PATCH v3 05/11] nouveau: use common screen ref counting

Ilia Mirkin imirkin at alum.mit.edu
Wed Jul 20 22:32:49 UTC 2016


On Wed, Jul 20, 2016 at 6:29 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Wed, Jul 20, 2016 at 6:25 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 68d8317..591cf92 100644
>> --- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>> +++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>> @@ -408,9 +408,6 @@ 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 303ecf1..7dbf66f 100644
>> --- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>> +++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>> @@ -428,9 +428,6 @@ 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 f681631..f789de4 100644
>> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> @@ -485,9 +485,6 @@ 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 f90572f..9ad3c57 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);
>
> I haven't looked at any other bits of the change, but this still has
> to be the dupfd. I think that's pscreen->fd in your updated series.

Oh, except you can't do that because the screen hasn't been created
yet. Well, either way, this has to be a dup'd fd.

  -ilia

>
>>         if (ret)
>>                 goto err;
>>
>> @@ -136,13 +69,7 @@ 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:
>> @@ -151,8 +78,6 @@ err:
>>         } else {
>>                 nouveau_device_del(&dev);
>>                 nouveau_drm_del(&drm);
>> -               close(dupfd);
>>         }
>> -       pipe_mutex_unlock(nouveau_screen_mutex);
>>         return NULL;
>>  }
>> --
>> 2.9.2
>>


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