[Nouveau] [PATCH] nouveau: safen up nouveau_device list usage against concurrent access

[Ben Skeggs]

On Thu, Mar 13, 2014 at 12:05 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Already said on IRC, but for posterity:

Reviewed-by: Ben Skeggs <bskeggs at redhat.com>

> ---
>  nouveau/nouveau.c | 29 ++++++++++++++++++++++++++++-
>  nouveau/private.h |  3 ++-
>  2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/nouveau/nouveau.c b/nouveau/nouveau.c
> index ee7893b..72c31cf 100644
> --- a/nouveau/nouveau.c
> +++ b/nouveau/nouveau.c
> @@ -85,6 +85,12 @@ nouveau_device_wrap(int fd, int close, struct nouveau_device **pdev)
>
>         if (!nvdev)
>                 return -ENOMEM;
> +       ret = pthread_mutex_init(&nvdev->lock, NULL);
> +       if (ret) {
> +               free(nvdev);
> +               return ret;
> +       }
> +
>         nvdev->base.fd = fd;
>
>         ver = drmGetVersion(fd);
> @@ -161,6 +167,7 @@ nouveau_device_del(struct nouveau_device **pdev)
>                 if (nvdev->close)
>                         drmClose(nvdev->base.fd);
>                 free(nvdev->client);
> +               pthread_mutex_destroy(&nvdev->lock);
>                 free(nvdev);
>                 *pdev = NULL;
>         }
> @@ -191,6 +198,8 @@ nouveau_client_new(struct nouveau_device *dev, struct nouveau_client **pclient)
>         int id = 0, i, ret = -ENOMEM;
>         uint32_t *clients;
>
> +       pthread_mutex_lock(&nvdev->lock);
> +
>         for (i = 0; i < nvdev->nr_client; i++) {
>                 id = ffs(nvdev->client[i]) - 1;
>                 if (id >= 0)
> @@ -199,7 +208,7 @@ nouveau_client_new(struct nouveau_device *dev, struct nouveau_client **pclient)
>
>         clients = realloc(nvdev->client, sizeof(uint32_t) * (i + 1));
>         if (!clients)
> -               return ret;
> +               goto unlock;
>         nvdev->client = clients;
>         nvdev->client[i] = 0;
>         nvdev->nr_client++;
> @@ -214,6 +223,9 @@ out:
>         }
>
>         *pclient = &pcli->base;
> +
> +unlock:
> +       pthread_mutex_unlock(&nvdev->lock);
>         return ret;
>  }
>
> @@ -225,7 +237,9 @@ nouveau_client_del(struct nouveau_client **pclient)
>         if (pcli) {
>                 int id = pcli->base.id;
>                 nvdev = nouveau_device(pcli->base.device);
> +               pthread_mutex_lock(&nvdev->lock);
>                 nvdev->client[id / 32] &= ~(1 << (id % 32));
> +               pthread_mutex_unlock(&nvdev->lock);
>                 free(pcli->kref);
>                 free(pcli);
>         }
> @@ -331,9 +345,12 @@ nouveau_object_find(struct nouveau_object *obj, uint32_t pclass)
>  static void
>  nouveau_bo_del(struct nouveau_bo *bo)
>  {
> +       struct nouveau_device_priv *nvdev = nouveau_device(bo->device);
>         struct nouveau_bo_priv *nvbo = nouveau_bo(bo);
>         struct drm_gem_close req = { bo->handle };
> +       pthread_mutex_lock(&nvdev->lock);
>         DRMLISTDEL(&nvbo->head);
> +       pthread_mutex_unlock(&nvdev->lock);
>         if (bo->map)
>                 munmap(bo->map, bo->size);
>         drmIoctl(bo->device->fd, DRM_IOCTL_GEM_CLOSE, &req);
> @@ -363,7 +380,9 @@ nouveau_bo_new(struct nouveau_device *dev, uint32_t flags, uint32_t align,
>                 return ret;
>         }
>
> +       pthread_mutex_lock(&nvdev->lock);
>         DRMLISTADD(&nvbo->head, &nvdev->bo_list);
> +       pthread_mutex_unlock(&nvdev->lock);
>
>         *pbo = bo;
>         return 0;
> @@ -378,13 +397,16 @@ nouveau_bo_wrap(struct nouveau_device *dev, uint32_t handle,
>         struct nouveau_bo_priv *nvbo;
>         int ret;
>
> +       pthread_mutex_lock(&nvdev->lock);
>         DRMLISTFOREACHENTRY(nvbo, &nvdev->bo_list, head) {
>                 if (nvbo->base.handle == handle) {
> +                       pthread_mutex_unlock(&nvdev->lock);
>                         *pbo = NULL;
>                         nouveau_bo_ref(&nvbo->base, pbo);
>                         return 0;
>                 }
>         }
> +       pthread_mutex_unlock(&nvdev->lock);
>
>         ret = drmCommandWriteRead(dev->fd, DRM_NOUVEAU_GEM_INFO,
>                                   &req, sizeof(req));
> @@ -396,7 +418,9 @@ nouveau_bo_wrap(struct nouveau_device *dev, uint32_t handle,
>                 atomic_set(&nvbo->refcnt, 1);
>                 nvbo->base.device = dev;
>                 abi16_bo_info(&nvbo->base, &req);
> +               pthread_mutex_lock(&nvdev->lock);
>                 DRMLISTADD(&nvbo->head, &nvdev->bo_list);
> +               pthread_mutex_unlock(&nvdev->lock);
>                 *pbo = &nvbo->base;
>                 return 0;
>         }
> @@ -413,13 +437,16 @@ nouveau_bo_name_ref(struct nouveau_device *dev, uint32_t name,
>         struct drm_gem_open req = { .name = name };
>         int ret;
>
> +       pthread_mutex_lock(&nvdev->lock);
>         DRMLISTFOREACHENTRY(nvbo, &nvdev->bo_list, head) {
>                 if (nvbo->name == name) {
> +                       pthread_mutex_unlock(&nvdev->lock);
>                         *pbo = NULL;
>                         nouveau_bo_ref(&nvbo->base, pbo);
>                         return 0;
>                 }
>         }
> +       pthread_mutex_unlock(&nvdev->lock);
>
>         ret = drmIoctl(dev->fd, DRM_IOCTL_GEM_OPEN, &req);
>         if (ret == 0) {
> diff --git a/nouveau/private.h b/nouveau/private.h
> index 60714b8..4f337ad 100644
> --- a/nouveau/private.h
> +++ b/nouveau/private.h
> @@ -3,6 +3,7 @@
>
>  #include <xf86drm.h>
>  #include <xf86atomic.h>
> +#include <pthread.h>
>  #include "nouveau_drm.h"
>
>  #include "nouveau.h"
> @@ -94,7 +95,7 @@ nouveau_bo(struct nouveau_bo *bo)
>  struct nouveau_device_priv {
>         struct nouveau_device base;
>         int close;
> -       atomic_t lock;
> +       pthread_mutex_t lock;
>         struct nouveau_list bo_list;
>         uint32_t *client;
>         int nr_client;
> --
> 1.8.3.2
>
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