Re: [RFC 01/10] drm: Track clients by tgid and not tid

[Tvrtko Ursulin]

Hi,

On 14/03/2023 15:33, Christian König wrote:
> Am 14.03.23 um 15:18 schrieb Tvrtko Ursulin:
> > From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> >
> > Thread group id (aka pid from userspace point of view) is a more
> > interesting thing to show as an owner of a DRM fd, so track and show that
> > instead of the thread id.
> >
> > In the next patch we will make the owner updated post file descriptor
> > handover, which will also be tgid based to avoid ping-pong when multiple
> > threads access the fd.
> >
> > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> > Cc: Zack Rusin <zackr@xxxxxxxxxx>
> > Cc: linux-graphics-maintainer@xxxxxxxxxx
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > Cc: "Christian König" <christian.koenig@xxxxxxx>
> > Reviewed-by: Zack Rusin <zackr@xxxxxxxxxx>
>
> Reviewed-by: Christian König <christian.koenig@xxxxxxx>
>
> Should we push the already reviewed cleanups like this one to 
> drm-misc-next? That makes sense even without the rest of the 
> functionality and reduce the amount of patches re-send.

I don't have the commit rights so if you could do that I certainly would 
not mind, thanks!

Regards,

Tvrtko

> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 2 +-
> >   drivers/gpu/drm/drm_debugfs.c           | 4 ++--
> >   drivers/gpu/drm/drm_file.c              | 2 +-
> >   drivers/gpu/drm/vmwgfx/vmwgfx_gem.c     | 2 +-
> >   4 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > index d8e683688daa..863cb668e000 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> > @@ -969,7 +969,7 @@ static int amdgpu_debugfs_gem_info_show(struct 
> > seq_file *m, void *unused)
> >            * Therefore, we need to protect this ->comm access using RCU.
> >            */
> >           rcu_read_lock();
> > -        task = pid_task(file->pid, PIDTYPE_PID);
> > +        task = pid_task(file->pid, PIDTYPE_TGID);
> >           seq_printf(m, "pid %8d command %s:\n", pid_nr(file->pid),
> >                  task ? task->comm : "<unknown>");
> >           rcu_read_unlock();
> > diff --git a/drivers/gpu/drm/drm_debugfs.c 
> > b/drivers/gpu/drm/drm_debugfs.c
> > index 4f643a490dc3..4855230ba2c6 100644
> > --- a/drivers/gpu/drm/drm_debugfs.c
> > +++ b/drivers/gpu/drm/drm_debugfs.c
> > @@ -80,7 +80,7 @@ static int drm_clients_info(struct seq_file *m, void 
> > *data)
> >       seq_printf(m,
> >              "%20s %5s %3s master a %5s %10s\n",
> >              "command",
> > -           "pid",
> > +           "tgid",
> >              "dev",
> >              "uid",
> >              "magic");
> > @@ -94,7 +94,7 @@ static int drm_clients_info(struct seq_file *m, void 
> > *data)
> >           bool is_current_master = drm_is_current_master(priv);
> >           rcu_read_lock(); /* locks pid_task()->comm */
> > -        task = pid_task(priv->pid, PIDTYPE_PID);
> > +        task = pid_task(priv->pid, PIDTYPE_TGID);
> >           uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID;
> >           seq_printf(m, "%20s %5d %3d   %c    %c %5d %10u\n",
> >                  task ? task->comm : "<unknown>",
> > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> > index a51ff8cee049..c1018c470047 100644
> > --- a/drivers/gpu/drm/drm_file.c
> > +++ b/drivers/gpu/drm/drm_file.c
> > @@ -156,7 +156,7 @@ struct drm_file *drm_file_alloc(struct drm_minor 
> > *minor)
> >       if (!file)
> >           return ERR_PTR(-ENOMEM);
> > -    file->pid = get_pid(task_pid(current));
> > +    file->pid = get_pid(task_tgid(current));
> >       file->minor = minor;
> >       /* for compatibility root is always authenticated */
> > diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c 
> > b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
> > index d6baf73a6458..c0da89e16e6f 100644
> > --- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
> > +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
> > @@ -241,7 +241,7 @@ static int vmw_debugfs_gem_info_show(struct 
> > seq_file *m, void *unused)
> >            * Therefore, we need to protect this ->comm access using RCU.
> >            */
> >           rcu_read_lock();
> > -        task = pid_task(file->pid, PIDTYPE_PID);
> > +        task = pid_task(file->pid, PIDTYPE_TGID);
> >           seq_printf(m, "pid %8d command %s:\n", pid_nr(file->pid),
> >                  task ? task->comm : "<unknown>");
> >           rcu_read_unlock();