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From: Chris Wilson <chris@chris-wilson.co.uk>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@intel.com>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Julia Lawall <julia.lawall@lip6.fr>
Subject: Re: [Intel-gfx] [PATCH 05/14] drm: Extract drm_master_open
Date: Wed, 15 Jun 2016 12:41:21 +0100	[thread overview]
Message-ID: <20160615114121.GI4184@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <1465930269-7883-6-git-send-email-daniel.vetter@ffwll.ch>

On Tue, Jun 14, 2016 at 08:51:00PM +0200, Daniel Vetter wrote:
> And pull out the primary_client check to make it really obvious that
> this can't happen on control/render nodes. Bonus that we can avoid the
> master lock in this case.

...as the minor->type is statically assigned on creation and so
inspection doesn't require the lock.

> v2: Don't leak locks on error path (and simplify control flow while
> at it), reported by Julia.
> 
> Cc: Julia Lawall <julia.lawall@lip6.fr>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/drm_auth.c     | 19 ++++++++++++++++++-
>  drivers/gpu/drm/drm_fops.c     | 13 ++-----------
>  drivers/gpu/drm/drm_internal.h |  2 +-
>  3 files changed, 21 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
> index 1d314ae13560..9c1e2081cd58 100644
> --- a/drivers/gpu/drm/drm_auth.c
> +++ b/drivers/gpu/drm/drm_auth.c
> @@ -120,7 +120,7 @@ static struct drm_master *drm_master_create(struct drm_device *dev)
>   * This function must be called with dev::struct_mutex held.
>   * Returns negative error code on failure. Zero on success.
>   */
> -int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
> +static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
>  {
>  	struct drm_master *old_master;
>  	int ret;
> @@ -226,6 +226,23 @@ out_unlock:
>  	return ret;
>  }
>  
> +int drm_master_open(struct drm_file *file_priv)
> +{
> +	struct drm_device *dev = file_priv->minor->dev;
> +	int ret = 0;
> +
> +	/* if there is no current master make this fd it, but do not create
> +	 * any master object for render clients */

The second half of this comment is out of place, it is referring to
drm_is_primary_client().

> +	mutex_lock(&dev->master_mutex);
> +	if (!file_priv->minor->master)
> +		ret = drm_new_set_master(dev, file_priv);
> +	else
> +		file_priv->master = drm_master_get(file_priv->minor->master);
> +	mutex_unlock(&dev->master_mutex);
> +
> +	return ret;
> +}
> +
>  struct drm_master *drm_master_get(struct drm_master *master)
>  {
>  	kref_get(&master->refcount);
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index 50b3de990aee..e2522672719a 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -229,19 +229,11 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
>  			goto out_prime_destroy;
>  	}
>  
> -	/* if there is no current master make this fd it, but do not create
> -	 * any master object for render clients */
> -	mutex_lock(&dev->master_mutex);
> -	if (drm_is_primary_client(priv) && !priv->minor->master) {
> -		/* create a new master */
> -		ret = drm_new_set_master(dev, priv);
> +	if (drm_is_primary_client(priv)) {
> +		ret = drm_master_open(priv);
>  		if (ret)

Both drm_is_primary_client() and drm_master_open() are acting on
drm_minor not drm_file. Idle speculation if that makes the code any
clearer.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply	other threads:[~2016-06-15 11:41 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-14 18:50 [PATCH 00/14] Cruft removal around drm_master Daniel Vetter
2016-06-14 18:50 ` [PATCH 01/14] drm: Nuke legacy maps debugfs files Daniel Vetter
2016-06-15 11:23   ` Chris Wilson
2016-06-15 12:00   ` Emil Velikov
2016-06-14 18:50 ` [PATCH 02/14] drm: Hide hw.lock cleanup in filp->release better Daniel Vetter
2016-06-15 11:26   ` [Intel-gfx] " Chris Wilson
2016-06-15 12:10   ` Emil Velikov
2016-06-14 18:50 ` [PATCH 03/14] drm: Link directly from drm_master to drm_device Daniel Vetter
2016-06-15 11:29   ` Chris Wilson
2016-06-15 12:50   ` [Intel-gfx] " Emil Velikov
2016-06-15 15:45     ` Daniel Vetter
2016-06-16 20:04       ` Emil Velikov
2016-06-14 18:50 ` [PATCH 04/14] drm: Move master functions into drm_auth.c Daniel Vetter
2016-06-15 11:31   ` Chris Wilson
2016-06-15 15:47     ` Daniel Vetter
2016-06-14 18:51 ` [PATCH 05/14] drm: Extract drm_master_open Daniel Vetter
2016-06-15 11:41   ` Chris Wilson [this message]
2016-06-14 18:51 ` [PATCH 06/14] drm: Extract drm_master_relase Daniel Vetter
2016-06-15 11:43   ` [Intel-gfx] " Chris Wilson
2016-06-16  8:18     ` Daniel Vetter
2016-06-14 18:51 ` [PATCH 07/14] drm: Only do the hw.lock cleanup in master_relase for !MODESET Daniel Vetter
2016-06-15 11:48   ` Chris Wilson
2016-06-15 15:49     ` [Intel-gfx] " Daniel Vetter
2016-06-14 18:51 ` [PATCH 08/14] drm: Move authmagic cleanup into drm_master_release Daniel Vetter
2016-06-15 11:51   ` Chris Wilson
2016-06-14 18:51 ` [PATCH 09/14] drm: Protect authmagic with master_mutex Daniel Vetter
2016-06-15 11:54   ` [Intel-gfx] " Chris Wilson
2016-06-15 15:52     ` Daniel Vetter
2016-06-14 18:51 ` [PATCH 10/14] drm: Mark authmagic ioctls as unlocked Daniel Vetter
2016-06-15 11:55   ` [Intel-gfx] " Chris Wilson
2016-06-14 18:51 ` [PATCH 11/14] drm: Mark set/drop master ioctl " Daniel Vetter
2016-06-15 11:56   ` [Intel-gfx] " Chris Wilson
2016-06-14 18:51 ` [PATCH 12/14] drm: Move master pointer from drm_minor to drm_device Daniel Vetter
2016-06-15 12:10   ` [Intel-gfx] " Chris Wilson
2016-06-15 16:01     ` Daniel Vetter
2016-06-15 16:33       ` Chris Wilson
2016-06-15 19:54         ` [Intel-gfx] " Daniel Vetter
2016-06-14 18:51 ` [PATCH 13/14] drm: Clean up drm_crtc.h Daniel Vetter
2016-06-14 18:51 ` [PATCH 14/14] drm: Use dev->name as fallback for dev->unique Daniel Vetter
2016-06-15  5:42 ` ✓ Ro.CI.BAT: success for Cruft removal around drm_master Patchwork

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