* [PATCH] drm/i915: Remove locking for get-caching query
@ 2015-05-07 11:14 Chris Wilson
2015-05-07 13:22 ` Daniel Vetter
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Chris Wilson @ 2015-05-07 11:14 UTC (permalink / raw)
To: intel-gfx
Reading a single value from the object, the locking only provides futile
protection against userspace races. The locking is useless so remove it.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 2b2b74dbb446..d071d0af2a6c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3983,17 +3983,10 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
{
struct drm_i915_gem_caching *args = data;
struct drm_i915_gem_object *obj;
- int ret;
-
- ret = i915_mutex_lock_interruptible(dev);
- if (ret)
- return ret;
obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
- if (&obj->base == NULL) {
- ret = -ENOENT;
- goto unlock;
- }
+ if (&obj->base == NULL)
+ return -ENOENT;
switch (obj->cache_level) {
case I915_CACHE_LLC:
@@ -4010,10 +4003,8 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
break;
}
- drm_gem_object_unreference(&obj->base);
-unlock:
- mutex_unlock(&dev->struct_mutex);
- return ret;
+ drm_gem_object_unreference_unlocked(&obj->base);
+ return 0;
}
int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
--
2.1.4
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^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915: Remove locking for get-caching query
2015-05-07 11:14 [PATCH] drm/i915: Remove locking for get-caching query Chris Wilson
@ 2015-05-07 13:22 ` Daniel Vetter
2015-05-07 13:22 ` Chris Wilson
2015-05-07 13:45 ` Mika Kuoppala
2015-05-08 6:39 ` shuang.he
2 siblings, 1 reply; 5+ messages in thread
From: Daniel Vetter @ 2015-05-07 13:22 UTC (permalink / raw)
To: Chris Wilson; +Cc: intel-gfx
On Thu, May 07, 2015 at 12:14:55PM +0100, Chris Wilson wrote:
> Reading a single value from the object, the locking only provides futile
> protection against userspace races. The locking is useless so remove it.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 17 ++++-------------
> 1 file changed, 4 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 2b2b74dbb446..d071d0af2a6c 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3983,17 +3983,10 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
> {
> struct drm_i915_gem_caching *args = data;
> struct drm_i915_gem_object *obj;
> - int ret;
> -
> - ret = i915_mutex_lock_interruptible(dev);
> - if (ret)
> - return ret;
>
> obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
> - if (&obj->base == NULL) {
> - ret = -ENOENT;
> - goto unlock;
> - }
> + if (&obj->base == NULL)
> + return -ENOENT;
>
> switch (obj->cache_level) {
Wrap this in ACCESS_ONCE, just for documentation purpose? Can do while
applying if you ack.
-Daniel
> case I915_CACHE_LLC:
> @@ -4010,10 +4003,8 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
> break;
> }
>
> - drm_gem_object_unreference(&obj->base);
> -unlock:
> - mutex_unlock(&dev->struct_mutex);
> - return ret;
> + drm_gem_object_unreference_unlocked(&obj->base);
> + return 0;
> }
>
> int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
> --
> 2.1.4
>
> _______________________________________________
> 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
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915: Remove locking for get-caching query
2015-05-07 13:22 ` Daniel Vetter
@ 2015-05-07 13:22 ` Chris Wilson
0 siblings, 0 replies; 5+ messages in thread
From: Chris Wilson @ 2015-05-07 13:22 UTC (permalink / raw)
To: Daniel Vetter; +Cc: intel-gfx
On Thu, May 07, 2015 at 03:22:41PM +0200, Daniel Vetter wrote:
> On Thu, May 07, 2015 at 12:14:55PM +0100, Chris Wilson wrote:
> > Reading a single value from the object, the locking only provides futile
> > protection against userspace races. The locking is useless so remove it.
> >
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > ---
> > drivers/gpu/drm/i915/i915_gem.c | 17 ++++-------------
> > 1 file changed, 4 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index 2b2b74dbb446..d071d0af2a6c 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -3983,17 +3983,10 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
> > {
> > struct drm_i915_gem_caching *args = data;
> > struct drm_i915_gem_object *obj;
> > - int ret;
> > -
> > - ret = i915_mutex_lock_interruptible(dev);
> > - if (ret)
> > - return ret;
> >
> > obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
> > - if (&obj->base == NULL) {
> > - ret = -ENOENT;
> > - goto unlock;
> > - }
> > + if (&obj->base == NULL)
> > + return -ENOENT;
> >
> > switch (obj->cache_level) {
>
> Wrap this in ACCESS_ONCE, just for documentation purpose? Can do while
> applying if you ack.
I was going to but I thought obj->cache_level was another bitfield... It
is :|
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/i915: Remove locking for get-caching query
2015-05-07 11:14 [PATCH] drm/i915: Remove locking for get-caching query Chris Wilson
2015-05-07 13:22 ` Daniel Vetter
@ 2015-05-07 13:45 ` Mika Kuoppala
2015-05-08 6:39 ` shuang.he
2 siblings, 0 replies; 5+ messages in thread
From: Mika Kuoppala @ 2015-05-07 13:45 UTC (permalink / raw)
To: Chris Wilson, intel-gfx
Chris Wilson <chris@chris-wilson.co.uk> writes:
> Reading a single value from the object, the locking only provides futile
> protection against userspace races. The locking is useless so remove it.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 17 ++++-------------
> 1 file changed, 4 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 2b2b74dbb446..d071d0af2a6c 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3983,17 +3983,10 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
> {
> struct drm_i915_gem_caching *args = data;
> struct drm_i915_gem_object *obj;
> - int ret;
> -
> - ret = i915_mutex_lock_interruptible(dev);
> - if (ret)
> - return ret;
>
> obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle));
> - if (&obj->base == NULL) {
> - ret = -ENOENT;
> - goto unlock;
> - }
> + if (&obj->base == NULL)
> + return -ENOENT;
>
> switch (obj->cache_level) {
> case I915_CACHE_LLC:
> @@ -4010,10 +4003,8 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data,
> break;
> }
>
> - drm_gem_object_unreference(&obj->base);
> -unlock:
> - mutex_unlock(&dev->struct_mutex);
> - return ret;
> + drm_gem_object_unreference_unlocked(&obj->base);
> + return 0;
> }
>
> int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data,
> --
> 2.1.4
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] drm/i915: Remove locking for get-caching query
2015-05-07 11:14 [PATCH] drm/i915: Remove locking for get-caching query Chris Wilson
2015-05-07 13:22 ` Daniel Vetter
2015-05-07 13:45 ` Mika Kuoppala
@ 2015-05-08 6:39 ` shuang.he
2 siblings, 0 replies; 5+ messages in thread
From: shuang.he @ 2015-05-08 6:39 UTC (permalink / raw)
To: shuang.he, ethan.gao, intel-gfx, chris
Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com)
Task id: 6343
-------------------------------------Summary-------------------------------------
Platform Delta drm-intel-nightly Series Applied
PNV -1 199/199 198/199
ILK 302/302 302/302
SNB 316/316 316/316
IVB 342/342 342/342
BYT 286/286 286/286
BDW 321/321 321/321
-------------------------------------Detailed-------------------------------------
Platform Test drm-intel-nightly Series Applied
*PNV igt@gem_userptr_blits@forked-sync-swapping-interruptible PASS(1) INIT(1)
Note: You need to pay more attention to line start with '*'
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-05-07 11:14 [PATCH] drm/i915: Remove locking for get-caching query Chris Wilson
2015-05-07 13:22 ` Daniel Vetter
2015-05-07 13:22 ` Chris Wilson
2015-05-07 13:45 ` Mika Kuoppala
2015-05-08 6:39 ` shuang.he
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