diff mbox series

[14/28] drm/i915: Take object lock in i915_ggtt_pin if ww is not set

Message ID 20211021103605.735002-14-maarten.lankhorst@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series [01/28] drm/i915: Fix i915_request fence wait semantics | expand

Commit Message

Maarten Lankhorst Oct. 21, 2021, 10:35 a.m. UTC 
i915_vma_wait_for_bind needs the vma lock held, fix the caller.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_vma.c | 40 +++++++++++++++++++++++----------
 1 file changed, 28 insertions(+), 12 deletions(-)

Comments

Matthew Auld Oct. 21, 2021, 5:39 p.m. UTC | #1 
On Thu, 21 Oct 2021 at 11:37, Maarten Lankhorst
<maarten.lankhorst@linux.intel.com> wrote:
>
> i915_vma_wait_for_bind needs the vma lock held, fix the caller.
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_vma.c | 40 +++++++++++++++++++++++----------
>  1 file changed, 28 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index bacc8d68e495..2877dcd62acb 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -1348,23 +1348,15 @@ static void flush_idle_contexts(struct intel_gt *gt)
>         intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
>  }
>
> -int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
> -                 u32 align, unsigned int flags)
> +static int __i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
> +                          u32 align, unsigned int flags)
>  {
>         struct i915_address_space *vm = vma->vm;
>         int err;
>
> -       GEM_BUG_ON(!i915_vma_is_ggtt(vma));
> -
> -#ifdef CONFIG_LOCKDEP
> -       WARN_ON(!ww && dma_resv_held(vma->obj->base.resv));
> -#endif
> -
>         do {
> -               if (ww)
> -                       err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
> -               else
> -                       err = i915_vma_pin(vma, 0, align, flags | PIN_GLOBAL);
> +               err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
> +
>                 if (err != -ENOSPC) {
>                         if (!err) {
>                                 err = i915_vma_wait_for_bind(vma);
> @@ -1383,6 +1375,30 @@ int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>         } while (1);
>  }
>
> +int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
> +                 u32 align, unsigned int flags)
> +{
> +       struct i915_gem_ww_ctx _ww;
> +       int err;
> +
> +       GEM_BUG_ON(!i915_vma_is_ggtt(vma));
> +
> +       if (ww)
> +               return __i915_ggtt_pin(vma, ww, align, flags);
> +
> +#ifdef CONFIG_LOCKDEP
> +       WARN_ON(dma_resv_held(vma->obj->base.resv));

Hmm, so this can't trigger, say if shrinker grabs the lock, or some
other concurrent user?

> +#endif
> +
> +       for_i915_gem_ww(&_ww, err, true) {
> +               err = i915_gem_object_lock(vma->obj, &_ww);
> +               if (!err)
> +                       err = __i915_ggtt_pin(vma, &_ww, align, flags);
> +       }
> +
> +       return err;
> +}
> +
>  static void __vma_close(struct i915_vma *vma, struct intel_gt *gt)
>  {
>         /*
> --
> 2.33.0
>
Maarten Lankhorst Nov. 29, 2021, 12:46 p.m. UTC | #2 
On 21-10-2021 19:39, Matthew Auld wrote:
> On Thu, 21 Oct 2021 at 11:37, Maarten Lankhorst
> <maarten.lankhorst@linux.intel.com> wrote:
>> i915_vma_wait_for_bind needs the vma lock held, fix the caller.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> ---
>>  drivers/gpu/drm/i915/i915_vma.c | 40 +++++++++++++++++++++++----------
>>  1 file changed, 28 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
>> index bacc8d68e495..2877dcd62acb 100644
>> --- a/drivers/gpu/drm/i915/i915_vma.c
>> +++ b/drivers/gpu/drm/i915/i915_vma.c
>> @@ -1348,23 +1348,15 @@ static void flush_idle_contexts(struct intel_gt *gt)
>>         intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
>>  }
>>
>> -int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>> -                 u32 align, unsigned int flags)
>> +static int __i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>> +                          u32 align, unsigned int flags)
>>  {
>>         struct i915_address_space *vm = vma->vm;
>>         int err;
>>
>> -       GEM_BUG_ON(!i915_vma_is_ggtt(vma));
>> -
>> -#ifdef CONFIG_LOCKDEP
>> -       WARN_ON(!ww && dma_resv_held(vma->obj->base.resv));
>> -#endif
>> -
>>         do {
>> -               if (ww)
>> -                       err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
>> -               else
>> -                       err = i915_vma_pin(vma, 0, align, flags | PIN_GLOBAL);
>> +               err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
>> +
>>                 if (err != -ENOSPC) {
>>                         if (!err) {
>>                                 err = i915_vma_wait_for_bind(vma);
>> @@ -1383,6 +1375,30 @@ int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>>         } while (1);
>>  }
>>
>> +int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
>> +                 u32 align, unsigned int flags)
>> +{
>> +       struct i915_gem_ww_ctx _ww;
>> +       int err;
>> +
>> +       GEM_BUG_ON(!i915_vma_is_ggtt(vma));
>> +
>> +       if (ww)
>> +               return __i915_ggtt_pin(vma, ww, align, flags);
>> +
>> +#ifdef CONFIG_LOCKDEP
>> +       WARN_ON(dma_resv_held(vma->obj->base.resv));
> Hmm, so this can't trigger, say if shrinker grabs the lock, or some
> other concurrent user?

No, it checks internally in lockdep that the current task doesn't hold the lock. Others can lock just fine.

dma_resv_is_locked() would check if anyone locked it. :)

~Maarten
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index bacc8d68e495..2877dcd62acb 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1348,23 +1348,15 @@  static void flush_idle_contexts(struct intel_gt *gt)
 	intel_gt_wait_for_idle(gt, MAX_SCHEDULE_TIMEOUT);
 }
 
-int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
-		  u32 align, unsigned int flags)
+static int __i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
+			   u32 align, unsigned int flags)
 {
 	struct i915_address_space *vm = vma->vm;
 	int err;
 
-	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
-
-#ifdef CONFIG_LOCKDEP
-	WARN_ON(!ww && dma_resv_held(vma->obj->base.resv));
-#endif
-
 	do {
-		if (ww)
-			err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
-		else
-			err = i915_vma_pin(vma, 0, align, flags | PIN_GLOBAL);
+		err = i915_vma_pin_ww(vma, ww, 0, align, flags | PIN_GLOBAL);
+
 		if (err != -ENOSPC) {
 			if (!err) {
 				err = i915_vma_wait_for_bind(vma);
@@ -1383,6 +1375,30 @@  int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
 	} while (1);
 }
 
+int i915_ggtt_pin(struct i915_vma *vma, struct i915_gem_ww_ctx *ww,
+		  u32 align, unsigned int flags)
+{
+	struct i915_gem_ww_ctx _ww;
+	int err;
+
+	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
+
+	if (ww)
+		return __i915_ggtt_pin(vma, ww, align, flags);
+
+#ifdef CONFIG_LOCKDEP
+	WARN_ON(dma_resv_held(vma->obj->base.resv));
+#endif
+
+	for_i915_gem_ww(&_ww, err, true) {
+		err = i915_gem_object_lock(vma->obj, &_ww);
+		if (!err)
+			err = __i915_ggtt_pin(vma, &_ww, align, flags);
+	}
+
+	return err;
+}
+
 static void __vma_close(struct i915_vma *vma, struct intel_gt *gt)
 {
 	/*