Balances the qxl_create_bo(..., pinned=true, ...);
call in qxl_release_bo_alloc().
Signed-off-by: Gerd Hoffmann <[email protected]>
---
drivers/gpu/drm/qxl/qxl_release.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 0fcfc952d5e9..add979cba11b 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
entry = container_of(release->bos.next,
struct qxl_bo_list, tv.head);
bo = to_qxl_bo(entry->tv.bo);
+ bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
qxl_bo_unref(&bo);
list_del(&entry->tv.head);
kfree(entry);
--
2.29.2
Hi
Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> Balances the qxl_create_bo(..., pinned=true, ...);
> call in qxl_release_bo_alloc().
>
> Signed-off-by: Gerd Hoffmann <[email protected]>
> ---
> drivers/gpu/drm/qxl/qxl_release.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> index 0fcfc952d5e9..add979cba11b 100644
> --- a/drivers/gpu/drm/qxl/qxl_release.c
> +++ b/drivers/gpu/drm/qxl/qxl_release.c
> @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
> entry = container_of(release->bos.next,
> struct qxl_bo_list, tv.head);
> bo = to_qxl_bo(entry->tv.bo);
> + bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
This code looks like a workaround or a bug.
AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can
you remove the pinned flag entirely and handle pinning as part of
dumb_shadow_bo's code.
Otherwise maybe use
if (pin_count)
ttm_bo_unpin();
WARN_ON(pin_count); /* should always be 0 now */
with a comment similar to the commit's description.
Best regards
Thomas
> qxl_bo_unref(&bo);
> list_del(&entry->tv.head);
> kfree(entry);
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
On Fri, Jan 22, 2021 at 09:13:42AM +0100, Thomas Zimmermann wrote:
> Hi
>
> Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> > Balances the qxl_create_bo(..., pinned=true, ...);
> > call in qxl_release_bo_alloc().
> >
> > Signed-off-by: Gerd Hoffmann <[email protected]>
> > ---
> > drivers/gpu/drm/qxl/qxl_release.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> > index 0fcfc952d5e9..add979cba11b 100644
> > --- a/drivers/gpu/drm/qxl/qxl_release.c
> > +++ b/drivers/gpu/drm/qxl/qxl_release.c
> > @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
> > entry = container_of(release->bos.next,
> > struct qxl_bo_list, tv.head);
> > bo = to_qxl_bo(entry->tv.bo);
> > + bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
>
> This code looks like a workaround or a bug.
>
> AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can you
> remove the pinned flag entirely and handle pinning as part of
> dumb_shadow_bo's code.
No, the release objects are pinned too, and they must be
pinned (qxl commands are in there, and references are
placed in the qxl rings, so allowing them to roam is
a non-starter).
> if (pin_count)
> ttm_bo_unpin();
> WARN_ON(pin_count); /* should always be 0 now */
Well, the pin_count is 1 at this point.
No need for the if().
Just calling ttm_bo_unpin() here makes lockdep unhappy.
Not calling ttm_bo_unpin() makes ttm_bo_release() throw
a WARN() because of the pin.
Clearing pin_count (which is how ttm fixes things up
in the error path) works.
I'm open to better ideas.
take care,
Gerd
On Fri, Jan 22, 2021 at 2:35 PM Gerd Hoffmann <[email protected]> wrote:
>
> On Fri, Jan 22, 2021 at 09:13:42AM +0100, Thomas Zimmermann wrote:
> > Hi
> >
> > Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> > > Balances the qxl_create_bo(..., pinned=true, ...);
> > > call in qxl_release_bo_alloc().
> > >
> > > Signed-off-by: Gerd Hoffmann <[email protected]>
> > > ---
> > > drivers/gpu/drm/qxl/qxl_release.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> > > index 0fcfc952d5e9..add979cba11b 100644
> > > --- a/drivers/gpu/drm/qxl/qxl_release.c
> > > +++ b/drivers/gpu/drm/qxl/qxl_release.c
> > > @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
> > > entry = container_of(release->bos.next,
> > > struct qxl_bo_list, tv.head);
> > > bo = to_qxl_bo(entry->tv.bo);
> > > + bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
> >
> > This code looks like a workaround or a bug.
> >
> > AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can you
> > remove the pinned flag entirely and handle pinning as part of
> > dumb_shadow_bo's code.
>
> No, the release objects are pinned too, and they must be
> pinned (qxl commands are in there, and references are
> placed in the qxl rings, so allowing them to roam is
> a non-starter).
>
> > if (pin_count)
> > ttm_bo_unpin();
> > WARN_ON(pin_count); /* should always be 0 now */
>
> Well, the pin_count is 1 at this point.
> No need for the if().
>
> Just calling ttm_bo_unpin() here makes lockdep unhappy.
How does that one splat? But yeah if that's a problem should be
explained in the comment. I'd then also only do a pin_count--; to make
sure you can still catch other pin leaks if you have them. Setting it
to 0 kinda defeats the warning.
-Daniel
>
> Not calling ttm_bo_unpin() makes ttm_bo_release() throw
> a WARN() because of the pin.
>
> Clearing pin_count (which is how ttm fixes things up
> in the error path) works.
>
> I'm open to better ideas.
>
> take care,
> Gerd
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
> > Just calling ttm_bo_unpin() here makes lockdep unhappy.
>
> How does that one splat? But yeah if that's a problem should be
> explained in the comment. I'd then also only do a pin_count--; to make
> sure you can still catch other pin leaks if you have them. Setting it
> to 0 kinda defeats the warning.
Figured the unpin is at the completely wrong place while trying to
reproduce the lockdep splat ...
take care,
Gerd
From 43befab4a935114e8620af62781666fa81288255 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <[email protected]>
Date: Mon, 25 Jan 2021 13:10:50 +0100
Subject: [PATCH] drm/qxl: unpin release objects
Balances the qxl_create_bo(..., pinned=true, ...);
call in qxl_release_bo_alloc().
Signed-off-by: Gerd Hoffmann <[email protected]>
---
drivers/gpu/drm/qxl/qxl_release.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index c52412724c26..28013fd1f8ea 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -347,6 +347,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
mutex_lock(&qdev->release_mutex);
if (qdev->current_release_bo_offset[cur_idx] + 1 >= releases_per_bo[cur_idx]) {
+ qxl_bo_unpin(qdev->current_release_bo[cur_idx]);
qxl_bo_unref(&qdev->current_release_bo[cur_idx]);
qdev->current_release_bo_offset[cur_idx] = 0;
qdev->current_release_bo[cur_idx] = NULL;
--
2.29.2