[PATCH] gpu: drm: i915: Change return type to vm_fault_t

[PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Souptick Joarder]

Use new return type vm_fault_t for fault handler. For
now, this is just documenting that the function returns
a VM_FAULT value rather than an errno. Once all instances
are converted, vm_fault_t will become a distinct type.

Reference id -> 1c8f422059ae ("mm: change return type to
vm_fault_t")

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
---
 drivers/gpu/drm/i915/i915_drv.h |  3 ++-
 drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a42deeb..95b0d50 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -51,6 +51,7 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_auth.h>
 #include <drm/drm_cache.h>
+#include <linux/mm_types.h>

 #include "i915_params.h"
 #include "i915_reg.h"
@@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
 			   unsigned int flags);
 int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv);
 void i915_gem_resume(struct drm_i915_private *dev_priv);
-int i915_gem_fault(struct vm_fault *vmf);
+vm_fault_t i915_gem_fault(struct vm_fault *vmf);
 int i915_gem_object_wait(struct drm_i915_gem_object *obj,
 			 unsigned int flags,
 			 long timeout,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index dd89abd..bdac690 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
  * The current feature set supported by i915_gem_fault() and thus GTT mmaps
  * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
  */
-int i915_gem_fault(struct vm_fault *vmf)
+vm_fault_t i915_gem_fault(struct vm_fault *vmf)
 {
 #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
 	struct vm_area_struct *area = vmf->vma;
@@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
 	pgoff_t page_offset;
 	unsigned int flags;
 	int ret;
+	vm_fault_t retval;

 	/* We don't use vmf->pgoff since that has the fake offset */
 	page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
@@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
 		 * and so needs to be reported.
 		 */
 		if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
-			ret = VM_FAULT_SIGBUS;
+			retval = VM_FAULT_SIGBUS;
 			break;
 		}
 	case -EAGAIN:
@@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
 		 * EBUSY is ok: this just means that another thread
 		 * already did the job.
 		 */
-		ret = VM_FAULT_NOPAGE;
+		retval = VM_FAULT_NOPAGE;
 		break;
 	case -ENOMEM:
-		ret = VM_FAULT_OOM;
+		retval = VM_FAULT_OOM;
 		break;
 	case -ENOSPC:
 	case -EFAULT:
-		ret = VM_FAULT_SIGBUS;
+		retval = VM_FAULT_SIGBUS;
 		break;
 	default:
 		WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
-		ret = VM_FAULT_SIGBUS;
+		retval = VM_FAULT_SIGBUS;
 		break;
 	}
-	return ret;
+	return retval;
 }

 static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
--
1.9.1

Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Jani Nikula]

On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.
>
> Reference id -> 1c8f422059ae ("mm: change return type to
> vm_fault_t")
>
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
>  2 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index a42deeb..95b0d50 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -51,6 +51,7 @@
>  #include <drm/drm_gem.h>
>  #include <drm/drm_auth.h>
>  #include <drm/drm_cache.h>
> +#include <linux/mm_types.h>
>
>  #include "i915_params.h"
>  #include "i915_reg.h"
> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
>  			   unsigned int flags);
>  int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv);
>  void i915_gem_resume(struct drm_i915_private *dev_priv);
> -int i915_gem_fault(struct vm_fault *vmf);
> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
>  			 unsigned int flags,
>  			 long timeout,
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index dd89abd..bdac690 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
>   * The current feature set supported by i915_gem_fault() and thus GTT mmaps
>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
>   */
> -int i915_gem_fault(struct vm_fault *vmf)
> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
>  {
>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
>  	struct vm_area_struct *area = vmf->vma;
> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>  	pgoff_t page_offset;
>  	unsigned int flags;
>  	int ret;
> +	vm_fault_t retval;

What's the point of changing the name? An unnecessary change.

BR,
Jani.

>
>  	/* We don't use vmf->pgoff since that has the fake offset */
>  	page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>  		 * and so needs to be reported.
>  		 */
>  		if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
> -			ret = VM_FAULT_SIGBUS;
> +			retval = VM_FAULT_SIGBUS;
>  			break;
>  		}
>  	case -EAGAIN:
> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
>  		 * EBUSY is ok: this just means that another thread
>  		 * already did the job.
>  		 */
> -		ret = VM_FAULT_NOPAGE;
> +		retval = VM_FAULT_NOPAGE;
>  		break;
>  	case -ENOMEM:
> -		ret = VM_FAULT_OOM;
> +		retval = VM_FAULT_OOM;
>  		break;
>  	case -ENOSPC:
>  	case -EFAULT:
> -		ret = VM_FAULT_SIGBUS;
> +		retval = VM_FAULT_SIGBUS;
>  		break;
>  	default:
>  		WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
> -		ret = VM_FAULT_SIGBUS;
> +		retval = VM_FAULT_SIGBUS;
>  		break;
>  	}
> -	return ret;
> +	return retval;
>  }
>
>  static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
> --
> 1.9.1
>

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Souptick Joarder]

Not exactly. The plan for these patches is to introduce new vm_fault_t type
in vm_operations_struct fault handlers. It's now available in 4.17-rc1. We will
push all the required drivers/filesystem changes through different maintainers
to linus tree. Once everything is converted into vm_fault_t type then Changing
it from a signed to an unsigned int causes GCC to warn about an assignment
from an incompatible type -- int foo(void) is incompatible with
unsigned int foo(void).

Please refer 1c8f422059ae ("mm: change return type to vm_fault_t") in 4.17-rc1.

On Tue, Apr 17, 2018 at 8:59 PM, Jani Nikula
<jani.nikula@linux.intel.com> wrote:
> On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
>> Use new return type vm_fault_t for fault handler. For
>> now, this is just documenting that the function returns
>> a VM_FAULT value rather than an errno. Once all instances
>> are converted, vm_fault_t will become a distinct type.
>>
>> Reference id -> 1c8f422059ae ("mm: change return type to
>> vm_fault_t")
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> ---
>>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
>>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
>>  2 files changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index a42deeb..95b0d50 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -51,6 +51,7 @@
>>  #include <drm/drm_gem.h>
>>  #include <drm/drm_auth.h>
>>  #include <drm/drm_cache.h>
>> +#include <linux/mm_types.h>
>>
>>  #include "i915_params.h"
>>  #include "i915_reg.h"
>> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
>>                          unsigned int flags);
>>  int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv);
>>  void i915_gem_resume(struct drm_i915_private *dev_priv);
>> -int i915_gem_fault(struct vm_fault *vmf);
>> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
>>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
>>                        unsigned int flags,
>>                        long timeout,
>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
>> index dd89abd..bdac690 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
>>   * The current feature set supported by i915_gem_fault() and thus GTT mmaps
>>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
>>   */
>> -int i915_gem_fault(struct vm_fault *vmf)
>> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
>>  {
>>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
>>       struct vm_area_struct *area = vmf->vma;
>> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>>       pgoff_t page_offset;
>>       unsigned int flags;
>>       int ret;
>> +     vm_fault_t retval;
>
> What's the point of changing the name? An unnecessary change.
>
> BR,
> Jani.
>
>>
>>       /* We don't use vmf->pgoff since that has the fake offset */
>>       page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
>> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>>                * and so needs to be reported.
>>                */
>>               if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
>> -                     ret = VM_FAULT_SIGBUS;
>> +                     retval = VM_FAULT_SIGBUS;
>>                       break;
>>               }
>>       case -EAGAIN:
>> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
>>                * EBUSY is ok: this just means that another thread
>>                * already did the job.
>>                */
>> -             ret = VM_FAULT_NOPAGE;
>> +             retval = VM_FAULT_NOPAGE;
>>               break;
>>       case -ENOMEM:
>> -             ret = VM_FAULT_OOM;
>> +             retval = VM_FAULT_OOM;
>>               break;
>>       case -ENOSPC:
>>       case -EFAULT:
>> -             ret = VM_FAULT_SIGBUS;
>> +             retval = VM_FAULT_SIGBUS;
>>               break;
>>       default:
>>               WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
>> -             ret = VM_FAULT_SIGBUS;
>> +             retval = VM_FAULT_SIGBUS;
>>               break;
>>       }
>> -     return ret;
>> +     return retval;
>>  }
>>
>>  static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
>> --
>> 1.9.1
>>
>
> --
> Jani Nikula, Intel Open Source Technology Center

Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Matthew Wilcox]

On Tue, Apr 17, 2018 at 09:14:32PM +0530, Souptick Joarder wrote:
> Not exactly. The plan for these patches is to introduce new vm_fault_t type
> in vm_operations_struct fault handlers. It's now available in 4.17-rc1. We will
> push all the required drivers/filesystem changes through different maintainers
> to linus tree. Once everything is converted into vm_fault_t type then Changing
> it from a signed to an unsigned int causes GCC to warn about an assignment
> from an incompatible type -- int foo(void) is incompatible with
> unsigned int foo(void).
> 
> Please refer 1c8f422059ae ("mm: change return type to vm_fault_t") in 4.17-rc1.

I think this patch would be clearer if you did

-	int ret;
+	int err;
+	vm_fault_t ret;

Then it would be clearer to the maintainer that you're splitting apart the
VM_FAULT and errno codes.

Sorry for not catching this during initial review.

> On Tue, Apr 17, 2018 at 8:59 PM, Jani Nikula
> <jani.nikula@linux.intel.com> wrote:
> > On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
> >> Use new return type vm_fault_t for fault handler. For
> >> now, this is just documenting that the function returns
> >> a VM_FAULT value rather than an errno. Once all instances
> >> are converted, vm_fault_t will become a distinct type.
> >>
> >> Reference id -> 1c8f422059ae ("mm: change return type to
> >> vm_fault_t")
> >>
> >> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> >> ---
> >>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
> >>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
> >>  2 files changed, 10 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> >> index a42deeb..95b0d50 100644
> >> --- a/drivers/gpu/drm/i915/i915_drv.h
> >> +++ b/drivers/gpu/drm/i915/i915_drv.h
> >> @@ -51,6 +51,7 @@
> >>  #include <drm/drm_gem.h>
> >>  #include <drm/drm_auth.h>
> >>  #include <drm/drm_cache.h>
> >> +#include <linux/mm_types.h>
> >>
> >>  #include "i915_params.h"
> >>  #include "i915_reg.h"
> >> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
> >>                          unsigned int flags);
> >>  int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv);
> >>  void i915_gem_resume(struct drm_i915_private *dev_priv);
> >> -int i915_gem_fault(struct vm_fault *vmf);
> >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
> >>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
> >>                        unsigned int flags,
> >>                        long timeout,
> >> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> >> index dd89abd..bdac690 100644
> >> --- a/drivers/gpu/drm/i915/i915_gem.c
> >> +++ b/drivers/gpu/drm/i915/i915_gem.c
> >> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
> >>   * The current feature set supported by i915_gem_fault() and thus GTT mmaps
> >>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
> >>   */
> >> -int i915_gem_fault(struct vm_fault *vmf)
> >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
> >>  {
> >>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
> >>       struct vm_area_struct *area = vmf->vma;
> >> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
> >>       pgoff_t page_offset;
> >>       unsigned int flags;
> >>       int ret;
> >> +     vm_fault_t retval;
> >
> > What's the point of changing the name? An unnecessary change.
> >
> > BR,
> > Jani.
> >
> >>
> >>       /* We don't use vmf->pgoff since that has the fake offset */
> >>       page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
> >> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
> >>                * and so needs to be reported.
> >>                */
> >>               if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
> >> -                     ret = VM_FAULT_SIGBUS;
> >> +                     retval = VM_FAULT_SIGBUS;
> >>                       break;
> >>               }
> >>       case -EAGAIN:
> >> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
> >>                * EBUSY is ok: this just means that another thread
> >>                * already did the job.
> >>                */
> >> -             ret = VM_FAULT_NOPAGE;
> >> +             retval = VM_FAULT_NOPAGE;
> >>               break;
> >>       case -ENOMEM:
> >> -             ret = VM_FAULT_OOM;
> >> +             retval = VM_FAULT_OOM;
> >>               break;
> >>       case -ENOSPC:
> >>       case -EFAULT:
> >> -             ret = VM_FAULT_SIGBUS;
> >> +             retval = VM_FAULT_SIGBUS;
> >>               break;
> >>       default:
> >>               WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
> >> -             ret = VM_FAULT_SIGBUS;
> >> +             retval = VM_FAULT_SIGBUS;
> >>               break;
> >>       }
> >> -     return ret;
> >> +     return retval;
> >>  }
> >>
> >>  static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
> >> --
> >> 1.9.1
> >>
> >
> > --
> > Jani Nikula, Intel Open Source Technology Center

Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Jani Nikula]

On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
> On 17-Apr-2018 9:45 PM, "Matthew Wilcox" <willy@infradead.org> wrote:
>>
>> On Tue, Apr 17, 2018 at 09:14:32PM +0530, Souptick Joarder wrote:
>> > Not exactly. The plan for these patches is to introduce new vm_fault_t
> type
>> > in vm_operations_struct fault handlers. It's now available in 4.17-rc1.
> We will
>> > push all the required drivers/filesystem changes through different
> maintainers
>> > to linus tree. Once everything is converted into vm_fault_t type then
> Changing
>> > it from a signed to an unsigned int causes GCC to warn about an
> assignment
>> > from an incompatible type -- int foo(void) is incompatible with
>> > unsigned int foo(void).
>> >
>> > Please refer 1c8f422059ae ("mm: change return type to vm_fault_t") in
> 4.17-rc1.
>>
>> I think this patch would be clearer if you did
>>
>> -       int ret;
>> +       int err;
>> +       vm_fault_t ret;
>>
>> Then it would be clearer to the maintainer that you're splitting apart the
>> VM_FAULT and errno codes.
>>
>> Sorry for not catching this during initial review.
>
> Ok, I will make required changes and send v2. Sorry, even I missed this :)

I'm afraid Daniel is closer to the truth. My bad, sorry for the noise.

BR,
Jani.



>>
>> > On Tue, Apr 17, 2018 at 8:59 PM, Jani Nikula
>> > <jani.nikula@linux.intel.com> wrote:
>> > > On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
>> > >> Use new return type vm_fault_t for fault handler. For
>> > >> now, this is just documenting that the function returns
>> > >> a VM_FAULT value rather than an errno. Once all instances
>> > >> are converted, vm_fault_t will become a distinct type.
>> > >>
>> > >> Reference id -> 1c8f422059ae ("mm: change return type to
>> > >> vm_fault_t")
>> > >>
>> > >> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> > >> ---
>> > >>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
>> > >>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
>> > >>  2 files changed, 10 insertions(+), 8 deletions(-)
>> > >>
>> > >> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
>> > >> index a42deeb..95b0d50 100644
>> > >> --- a/drivers/gpu/drm/i915/i915_drv.h
>> > >> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> > >> @@ -51,6 +51,7 @@
>> > >>  #include <drm/drm_gem.h>
>> > >>  #include <drm/drm_auth.h>
>> > >>  #include <drm/drm_cache.h>
>> > >> +#include <linux/mm_types.h>
>> > >>
>> > >>  #include "i915_params.h"
>> > >>  #include "i915_reg.h"
>> > >> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct
> drm_i915_private *dev_priv,
>> > >>                          unsigned int flags);
>> > >>  int __must_check i915_gem_suspend(struct drm_i915_private
> *dev_priv);
>> > >>  void i915_gem_resume(struct drm_i915_private *dev_priv);
>> > >> -int i915_gem_fault(struct vm_fault *vmf);
>> > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
>> > >>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
>> > >>                        unsigned int flags,
>> > >>                        long timeout,
>> > >> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c
>> > >> index dd89abd..bdac690 100644
>> > >> --- a/drivers/gpu/drm/i915/i915_gem.c
>> > >> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> > >> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
>> > >>   * The current feature set supported by i915_gem_fault() and thus
> GTT mmaps
>> > >>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see
> i915_gem_mmap_gtt_version).
>> > >>   */
>> > >> -int i915_gem_fault(struct vm_fault *vmf)
>> > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
>> > >>  {
>> > >>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
>> > >>       struct vm_area_struct *area = vmf->vma;
>> > >> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>> > >>       pgoff_t page_offset;
>> > >>       unsigned int flags;
>> > >>       int ret;
>> > >> +     vm_fault_t retval;
>> > >
>> > > What's the point of changing the name? An unnecessary change.
>> > >
>> > > BR,
>> > > Jani.
>> > >
>> > >>
>> > >>       /* We don't use vmf->pgoff since that has the fake offset */
>> > >>       page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
>> > >> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>> > >>                * and so needs to be reported.
>> > >>                */
>> > >>               if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
>> > >> -                     ret = VM_FAULT_SIGBUS;
>> > >> +                     retval = VM_FAULT_SIGBUS;
>> > >>                       break;
>> > >>               }
>> > >>       case -EAGAIN:
>> > >> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
>> > >>                * EBUSY is ok: this just means that another thread
>> > >>                * already did the job.
>> > >>                */
>> > >> -             ret = VM_FAULT_NOPAGE;
>> > >> +             retval = VM_FAULT_NOPAGE;
>> > >>               break;
>> > >>       case -ENOMEM:
>> > >> -             ret = VM_FAULT_OOM;
>> > >> +             retval = VM_FAULT_OOM;
>> > >>               break;
>> > >>       case -ENOSPC:
>> > >>       case -EFAULT:
>> > >> -             ret = VM_FAULT_SIGBUS;
>> > >> +             retval = VM_FAULT_SIGBUS;
>> > >>               break;
>> > >>       default:
>> > >>               WARN_ONCE(ret, "unhandled error in i915_gem_fault:
> %i\n", ret);
>> > >> -             ret = VM_FAULT_SIGBUS;
>> > >> +             retval = VM_FAULT_SIGBUS;
>> > >>               break;
>> > >>       }
>> > >> -     return ret;
>> > >> +     return retval;
>> > >>  }
>> > >>
>> > >>  static void __i915_gem_object_release_mmap(struct
> drm_i915_gem_object *obj)
>> > >> --
>> > >> 1.9.1
>> > >>
>> > >
>> > > --
>> > > Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center

Re: [Intel-gfx] [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Rodrigo Vivi]

On Wed, Apr 18, 2018 at 08:46:44AM +0300, Jani Nikula wrote:
> On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
> > On 17-Apr-2018 9:45 PM, "Matthew Wilcox" <willy@infradead.org> wrote:
> >>
> >> On Tue, Apr 17, 2018 at 09:14:32PM +0530, Souptick Joarder wrote:
> >> > Not exactly. The plan for these patches is to introduce new vm_fault_t
> > type
> >> > in vm_operations_struct fault handlers. It's now available in 4.17-rc1.
> > We will
> >> > push all the required drivers/filesystem changes through different
> > maintainers
> >> > to linus tree. Once everything is converted into vm_fault_t type then
> > Changing
> >> > it from a signed to an unsigned int causes GCC to warn about an
> > assignment
> >> > from an incompatible type -- int foo(void) is incompatible with
> >> > unsigned int foo(void).
> >> >
> >> > Please refer 1c8f422059ae ("mm: change return type to vm_fault_t") in
> > 4.17-rc1.
> >>
> >> I think this patch would be clearer if you did
> >>
> >> -       int ret;
> >> +       int err;
> >> +       vm_fault_t ret;
> >>
> >> Then it would be clearer to the maintainer that you're splitting apart the
> >> VM_FAULT and errno codes.
> >>
> >> Sorry for not catching this during initial review.
> >
> > Ok, I will make required changes and send v2. Sorry, even I missed this :)
> 
> I'm afraid Daniel is closer to the truth.

+1.

> My bad, sorry for the noise.

I opened this thread to add exactly question/noise ;).

So my recommendation for some next time is to make the intention clear
on the commit message itself from the begin.

> 
> BR,
> Jani.
> 
> 
> 
> >>
> >> > On Tue, Apr 17, 2018 at 8:59 PM, Jani Nikula
> >> > <jani.nikula@linux.intel.com> wrote:
> >> > > On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
> >> > >> Use new return type vm_fault_t for fault handler. For
> >> > >> now, this is just documenting that the function returns
> >> > >> a VM_FAULT value rather than an errno. Once all instances
> >> > >> are converted, vm_fault_t will become a distinct type.
> >> > >>
> >> > >> Reference id -> 1c8f422059ae ("mm: change return type to
> >> > >> vm_fault_t")
> >> > >>
> >> > >> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> >> > >> ---
> >> > >>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
> >> > >>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
> >> > >>  2 files changed, 10 insertions(+), 8 deletions(-)
> >> > >>
> >> > >> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > b/drivers/gpu/drm/i915/i915_drv.h
> >> > >> index a42deeb..95b0d50 100644
> >> > >> --- a/drivers/gpu/drm/i915/i915_drv.h
> >> > >> +++ b/drivers/gpu/drm/i915/i915_drv.h
> >> > >> @@ -51,6 +51,7 @@
> >> > >>  #include <drm/drm_gem.h>
> >> > >>  #include <drm/drm_auth.h>
> >> > >>  #include <drm/drm_cache.h>
> >> > >> +#include <linux/mm_types.h>
> >> > >>
> >> > >>  #include "i915_params.h"
> >> > >>  #include "i915_reg.h"
> >> > >> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct
> > drm_i915_private *dev_priv,
> >> > >>                          unsigned int flags);
> >> > >>  int __must_check i915_gem_suspend(struct drm_i915_private
> > *dev_priv);
> >> > >>  void i915_gem_resume(struct drm_i915_private *dev_priv);
> >> > >> -int i915_gem_fault(struct vm_fault *vmf);
> >> > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
> >> > >>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
> >> > >>                        unsigned int flags,
> >> > >>                        long timeout,
> >> > >> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> > b/drivers/gpu/drm/i915/i915_gem.c
> >> > >> index dd89abd..bdac690 100644
> >> > >> --- a/drivers/gpu/drm/i915/i915_gem.c
> >> > >> +++ b/drivers/gpu/drm/i915/i915_gem.c
> >> > >> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
> >> > >>   * The current feature set supported by i915_gem_fault() and thus
> > GTT mmaps
> >> > >>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see
> > i915_gem_mmap_gtt_version).
> >> > >>   */
> >> > >> -int i915_gem_fault(struct vm_fault *vmf)
> >> > >> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
> >> > >>  {
> >> > >>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
> >> > >>       struct vm_area_struct *area = vmf->vma;
> >> > >> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
> >> > >>       pgoff_t page_offset;
> >> > >>       unsigned int flags;
> >> > >>       int ret;
> >> > >> +     vm_fault_t retval;
> >> > >
> >> > > What's the point of changing the name? An unnecessary change.
> >> > >
> >> > > BR,
> >> > > Jani.
> >> > >
> >> > >>
> >> > >>       /* We don't use vmf->pgoff since that has the fake offset */
> >> > >>       page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
> >> > >> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
> >> > >>                * and so needs to be reported.
> >> > >>                */
> >> > >>               if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
> >> > >> -                     ret = VM_FAULT_SIGBUS;
> >> > >> +                     retval = VM_FAULT_SIGBUS;
> >> > >>                       break;
> >> > >>               }
> >> > >>       case -EAGAIN:
> >> > >> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
> >> > >>                * EBUSY is ok: this just means that another thread
> >> > >>                * already did the job.
> >> > >>                */
> >> > >> -             ret = VM_FAULT_NOPAGE;
> >> > >> +             retval = VM_FAULT_NOPAGE;
> >> > >>               break;
> >> > >>       case -ENOMEM:
> >> > >> -             ret = VM_FAULT_OOM;
> >> > >> +             retval = VM_FAULT_OOM;
> >> > >>               break;
> >> > >>       case -ENOSPC:
> >> > >>       case -EFAULT:
> >> > >> -             ret = VM_FAULT_SIGBUS;
> >> > >> +             retval = VM_FAULT_SIGBUS;
> >> > >>               break;
> >> > >>       default:
> >> > >>               WARN_ONCE(ret, "unhandled error in i915_gem_fault:
> > %i\n", ret);
> >> > >> -             ret = VM_FAULT_SIGBUS;
> >> > >> +             retval = VM_FAULT_SIGBUS;
> >> > >>               break;
> >> > >>       }
> >> > >> -     return ret;
> >> > >> +     return retval;
> >> > >>  }
> >> > >>
> >> > >>  static void __i915_gem_object_release_mmap(struct
> > drm_i915_gem_object *obj)
> >> > >> --
> >> > >> 1.9.1
> >> > >>
> >> > >
> >> > > --
> >> > > Jani Nikula, Intel Open Source Technology Center
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [PATCH] gpu: drm: i915: Change return type to vm_fault_t

[Daniel Vetter]

On Tue, Apr 17, 2018 at 5:29 PM, Jani Nikula
<jani.nikula@linux.intel.com> wrote:
> On Tue, 17 Apr 2018, Souptick Joarder <jrdr.linux@gmail.com> wrote:
>> Use new return type vm_fault_t for fault handler. For
>> now, this is just documenting that the function returns
>> a VM_FAULT value rather than an errno. Once all instances
>> are converted, vm_fault_t will become a distinct type.
>>
>> Reference id -> 1c8f422059ae ("mm: change return type to
>> vm_fault_t")
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>> ---
>>  drivers/gpu/drm/i915/i915_drv.h |  3 ++-
>>  drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++-------
>>  2 files changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index a42deeb..95b0d50 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -51,6 +51,7 @@
>>  #include <drm/drm_gem.h>
>>  #include <drm/drm_auth.h>
>>  #include <drm/drm_cache.h>
>> +#include <linux/mm_types.h>
>>
>>  #include "i915_params.h"
>>  #include "i915_reg.h"
>> @@ -3363,7 +3364,7 @@ int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
>>                          unsigned int flags);
>>  int __must_check i915_gem_suspend(struct drm_i915_private *dev_priv);
>>  void i915_gem_resume(struct drm_i915_private *dev_priv);
>> -int i915_gem_fault(struct vm_fault *vmf);
>> +vm_fault_t i915_gem_fault(struct vm_fault *vmf);
>>  int i915_gem_object_wait(struct drm_i915_gem_object *obj,
>>                        unsigned int flags,
>>                        long timeout,
>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
>> index dd89abd..bdac690 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -1882,7 +1882,7 @@ int i915_gem_mmap_gtt_version(void)
>>   * The current feature set supported by i915_gem_fault() and thus GTT mmaps
>>   * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
>>   */
>> -int i915_gem_fault(struct vm_fault *vmf)
>> +vm_fault_t i915_gem_fault(struct vm_fault *vmf)
>>  {
>>  #define MIN_CHUNK_PAGES ((1 << 20) >> PAGE_SHIFT) /* 1 MiB */
>>       struct vm_area_struct *area = vmf->vma;
>> @@ -1895,6 +1895,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>>       pgoff_t page_offset;
>>       unsigned int flags;
>>       int ret;
>> +     vm_fault_t retval;
>
> What's the point of changing the name? An unnecessary change.

int ret;

already exists and is used. You can't also have a vm_fault_t ret; on
top of that :-)
-Daniel

>
> BR,
> Jani.
>
>>
>>       /* We don't use vmf->pgoff since that has the fake offset */
>>       page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
>> @@ -2000,7 +2001,7 @@ int i915_gem_fault(struct vm_fault *vmf)
>>                * and so needs to be reported.
>>                */
>>               if (!i915_terminally_wedged(&dev_priv->gpu_error)) {
>> -                     ret = VM_FAULT_SIGBUS;
>> +                     retval = VM_FAULT_SIGBUS;
>>                       break;
>>               }
>>       case -EAGAIN:
>> @@ -2017,21 +2018,21 @@ int i915_gem_fault(struct vm_fault *vmf)
>>                * EBUSY is ok: this just means that another thread
>>                * already did the job.
>>                */
>> -             ret = VM_FAULT_NOPAGE;
>> +             retval = VM_FAULT_NOPAGE;
>>               break;
>>       case -ENOMEM:
>> -             ret = VM_FAULT_OOM;
>> +             retval = VM_FAULT_OOM;
>>               break;
>>       case -ENOSPC:
>>       case -EFAULT:
>> -             ret = VM_FAULT_SIGBUS;
>> +             retval = VM_FAULT_SIGBUS;
>>               break;
>>       default:
>>               WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
>> -             ret = VM_FAULT_SIGBUS;
>> +             retval = VM_FAULT_SIGBUS;
>>               break;
>>       }
>> -     return ret;
>> +     return retval;
>>  }
>>
>>  static void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
>> --
>> 1.9.1
>>
>
> --
> Jani Nikula, Intel Open Source Technology Center
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch