* [PATCH] drm/i915: Fix comparison bug
@ 2015-09-28 21:08 Rasmus Villemoes
2015-09-29 7:37 ` Jani Nikula
0 siblings, 1 reply; 4+ messages in thread
From: Rasmus Villemoes @ 2015-09-28 21:08 UTC (permalink / raw)
To: Daniel Vetter, Jani Nikula, David Airlie
Cc: Rasmus Villemoes, intel-gfx, dri-devel, linux-kernel
->stolen->start has type u64 aka unsigned long long; relying on the
difference (effectively cast to int) for sorting is wrong.
It wouldn't be a problem in practice if the values compared are always
within INT_MAX of each other (so that the difference is actually
representable in an int), but 440fd5283a87 ("drm/mm: Support 4 GiB and
larger ranges") strongly suggests that's not the case.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index e3ec9049081f..5207e681a987 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -258,7 +258,11 @@ static int obj_rank_by_stolen(void *priv,
struct drm_i915_gem_object *b =
container_of(B, struct drm_i915_gem_object, obj_exec_link);
- return a->stolen->start - b->stolen->start;
+ if (a->stolen->start < b->stolen->start)
+ return -1;
+ if (a->stolen->start > b->stolen->start)
+ return 1;
+ return 0;
}
static int i915_gem_stolen_list_info(struct seq_file *m, void *data)
--
2.1.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] drm/i915: Fix comparison bug
2015-09-28 21:08 [PATCH] drm/i915: Fix comparison bug Rasmus Villemoes
@ 2015-09-29 7:37 ` Jani Nikula
2015-09-29 7:43 ` Daniel Vetter
0 siblings, 1 reply; 4+ messages in thread
From: Jani Nikula @ 2015-09-29 7:37 UTC (permalink / raw)
To: Daniel Vetter, David Airlie
Cc: intel-gfx, Rasmus Villemoes, linux-kernel, dri-devel
On Tue, 29 Sep 2015, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:
> ->stolen->start has type u64 aka unsigned long long; relying on the
> difference (effectively cast to int) for sorting is wrong.
>
> It wouldn't be a problem in practice if the values compared are always
> within INT_MAX of each other (so that the difference is actually
> representable in an int), but 440fd5283a87 ("drm/mm: Support 4 GiB and
> larger ranges") strongly suggests that's not the case.
>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index e3ec9049081f..5207e681a987 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -258,7 +258,11 @@ static int obj_rank_by_stolen(void *priv,
> struct drm_i915_gem_object *b =
> container_of(B, struct drm_i915_gem_object, obj_exec_link);
>
> - return a->stolen->start - b->stolen->start;
> + if (a->stolen->start < b->stolen->start)
> + return -1;
> + if (a->stolen->start > b->stolen->start)
> + return 1;
> + return 0;
> }
>
> static int i915_gem_stolen_list_info(struct seq_file *m, void *data)
> --
> 2.1.3
>
--
Jani Nikula, Intel Open Source Technology Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm/i915: Fix comparison bug
2015-09-29 7:37 ` Jani Nikula
@ 2015-09-29 7:43 ` Daniel Vetter
0 siblings, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2015-09-29 7:43 UTC (permalink / raw)
To: Jani Nikula
Cc: David Airlie, intel-gfx, Rasmus Villemoes, linux-kernel,
dri-devel, Daniel Vetter
On Tue, Sep 29, 2015 at 10:37:30AM +0300, Jani Nikula wrote:
> On Tue, 29 Sep 2015, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:
> > ->stolen->start has type u64 aka unsigned long long; relying on the
> > difference (effectively cast to int) for sorting is wrong.
> >
> > It wouldn't be a problem in practice if the values compared are always
> > within INT_MAX of each other (so that the difference is actually
> > representable in an int), but 440fd5283a87 ("drm/mm: Support 4 GiB and
> > larger ranges") strongly suggests that's not the case.
> >
> > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
drm_mm is the shared gpu memmory manager, but stolen itself can only go to
about 1.5G currently. So safe, but I merged your patch anyway with a small
note added for 4.4.
Thanks, Daniel
>
>
> > ---
> > drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > index e3ec9049081f..5207e681a987 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -258,7 +258,11 @@ static int obj_rank_by_stolen(void *priv,
> > struct drm_i915_gem_object *b =
> > container_of(B, struct drm_i915_gem_object, obj_exec_link);
> >
> > - return a->stolen->start - b->stolen->start;
> > + if (a->stolen->start < b->stolen->start)
> > + return -1;
> > + if (a->stolen->start > b->stolen->start)
> > + return 1;
> > + return 0;
> > }
> >
> > static int i915_gem_stolen_list_info(struct seq_file *m, void *data)
> > --
> > 2.1.3
> >
>
> --
> Jani Nikula, Intel Open Source Technology Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] drm/i915: Fix comparison bug
@ 2014-12-07 21:26 Rasmus Villemoes
0 siblings, 0 replies; 4+ messages in thread
From: Rasmus Villemoes @ 2014-12-07 21:26 UTC (permalink / raw)
To: Daniel Vetter, Jani Nikula, David Airlie
Cc: Rasmus Villemoes, intel-gfx, dri-devel, linux-kernel
->stolen->start has type unsigned long; relying on the difference
(effectively cast to int) for sorting is wrong.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 063b44817e08..adfb863bb580 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -236,7 +236,11 @@ static int obj_rank_by_stolen(void *priv,
struct drm_i915_gem_object *b =
container_of(B, struct drm_i915_gem_object, obj_exec_link);
- return a->stolen->start - b->stolen->start;
+ if (a->stolen->start < b->stolen->start)
+ return -1;
+ if (a->stolen->start > b->stolen->start)
+ return 1;
+ return 0;
}
static int i915_gem_stolen_list_info(struct seq_file *m, void *data)
--
2.1.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2015-09-28 21:08 [PATCH] drm/i915: Fix comparison bug Rasmus Villemoes
2015-09-29 7:37 ` Jani Nikula
2015-09-29 7:43 ` Daniel Vetter
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2014-12-07 21:26 Rasmus Villemoes
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