[PATCH] s390/gmap: return proper error code on ksm unsharing

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* [PATCH] s390/gmap: return proper error code on ksm unsharing
@ 2020-03-27  8:56 Christian Borntraeger
  2020-03-27  8:59 ` Julian Wiedmann
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Christian Borntraeger @ 2020-03-27  8:56 UTC (permalink / raw)
  To: Christian Borntraeger, Janosch Frank
  Cc: KVM, David Hildenbrand, linux-s390, Cornelia Huck, Heiko Carstens

If a signal is pending we might return -ENOMEM instead of -EINTR.
We should propagate the proper error during KSM unsharing.

Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/mm/gmap.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 27926a06df32..2bf63035a295 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2552,15 +2552,16 @@ int gmap_mark_unmergeable(void)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	int ret  = 0;
 
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
-				MADV_UNMERGEABLE, &vma->vm_flags)) {
-			return -ENOMEM;
-		}
+		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
+				MADV_UNMERGEABLE, &vma->vm_flags);
+		if (ret)
+			return ret;
 	}
 	mm->def_flags &= ~VM_MERGEABLE;
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
 
-- 
2.25.1

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] s390/gmap: return proper error code on ksm unsharing
  2020-03-27  8:56 [PATCH] s390/gmap: return proper error code on ksm unsharing Christian Borntraeger
@ 2020-03-27  8:59 ` Julian Wiedmann
  2020-03-27  9:07 ` David Hildenbrand
  2020-03-27  9:10 ` Janosch Frank
  2 siblings, 0 replies; 5+ messages in thread
From: Julian Wiedmann @ 2020-03-27  8:59 UTC (permalink / raw)
  To: Christian Borntraeger, Janosch Frank
  Cc: KVM, David Hildenbrand, linux-s390, Cornelia Huck, Heiko Carstens

On 27.03.20 09:56, Christian Borntraeger wrote:
> If a signal is pending we might return -ENOMEM instead of -EINTR.
> We should propagate the proper error during KSM unsharing.
> 
> Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/mm/gmap.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 27926a06df32..2bf63035a295 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2552,15 +2552,16 @@ int gmap_mark_unmergeable(void)
>  {
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
> +	int ret  = 0;
>  

extra whitespace

>  	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> -		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
> -				MADV_UNMERGEABLE, &vma->vm_flags)) {
> -			return -ENOMEM;
> -		}
> +		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
> +				MADV_UNMERGEABLE, &vma->vm_flags);
> +		if (ret)
> +			return ret;
>  	}
>  	mm->def_flags &= ~VM_MERGEABLE;
> -	return 0;
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
>  
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] s390/gmap: return proper error code on ksm unsharing
  2020-03-27  8:56 [PATCH] s390/gmap: return proper error code on ksm unsharing Christian Borntraeger
  2020-03-27  8:59 ` Julian Wiedmann
@ 2020-03-27  9:07 ` David Hildenbrand
  2020-03-27  9:08   ` Christian Borntraeger
  2020-03-27  9:10 ` Janosch Frank
  2 siblings, 1 reply; 5+ messages in thread
From: David Hildenbrand @ 2020-03-27  9:07 UTC (permalink / raw)
  To: Christian Borntraeger, Janosch Frank
  Cc: KVM, linux-s390, Cornelia Huck, Heiko Carstens

On 27.03.20 09:56, Christian Borntraeger wrote:
> If a signal is pending we might return -ENOMEM instead of -EINTR.
> We should propagate the proper error during KSM unsharing.
> 
> Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  arch/s390/mm/gmap.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 27926a06df32..2bf63035a295 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2552,15 +2552,16 @@ int gmap_mark_unmergeable(void)
>  {
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
> +	int ret  = 0;
>  
>  	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> -		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
> -				MADV_UNMERGEABLE, &vma->vm_flags)) {
> -			return -ENOMEM;
> -		}
> +		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
> +				MADV_UNMERGEABLE, &vma->vm_flags);
> +		if (ret)
> +			return ret;
>  	}
>  	mm->def_flags &= ~VM_MERGEABLE;
> -	return 0;
> +	return ret;

How can this ever be !0 ?

Also, once removed, no need to initialize ret to 0.

>  }
>  EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
>  
> 


-- 
Thanks,

David / dhildenb

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] s390/gmap: return proper error code on ksm unsharing
  2020-03-27  9:07 ` David Hildenbrand
@ 2020-03-27  9:08   ` Christian Borntraeger
  0 siblings, 0 replies; 5+ messages in thread
From: Christian Borntraeger @ 2020-03-27  9:08 UTC (permalink / raw)
  To: David Hildenbrand, Janosch Frank
  Cc: KVM, linux-s390, Cornelia Huck, Heiko Carstens



On 27.03.20 10:07, David Hildenbrand wrote:
> On 27.03.20 09:56, Christian Borntraeger wrote:
>> If a signal is pending we might return -ENOMEM instead of -EINTR.
>> We should propagate the proper error during KSM unsharing.
>>
>> Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  arch/s390/mm/gmap.c | 11 ++++++-----
>>  1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
>> index 27926a06df32..2bf63035a295 100644
>> --- a/arch/s390/mm/gmap.c
>> +++ b/arch/s390/mm/gmap.c
>> @@ -2552,15 +2552,16 @@ int gmap_mark_unmergeable(void)
>>  {
>>  	struct mm_struct *mm = current->mm;
>>  	struct vm_area_struct *vma;
>> +	int ret  = 0;
>>  
>>  	for (vma = mm->mmap; vma; vma = vma->vm_next) {
>> -		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
>> -				MADV_UNMERGEABLE, &vma->vm_flags)) {
>> -			return -ENOMEM;
>> -		}
>> +		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
>> +				MADV_UNMERGEABLE, &vma->vm_flags);
>> +		if (ret)
>> +			return ret;
>>  	}
>>  	mm->def_flags &= ~VM_MERGEABLE;
>> -	return 0;
>> +	return ret;
> 
> How can this ever be !0 ?
> 
> Also, once removed, no need to initialize ret to 0.

Right, I can make the patch smaller by keeping the return 0;

> 
>>  }
>>  EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
>>  
>>
> 
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] s390/gmap: return proper error code on ksm unsharing
  2020-03-27  8:56 [PATCH] s390/gmap: return proper error code on ksm unsharing Christian Borntraeger
  2020-03-27  8:59 ` Julian Wiedmann
  2020-03-27  9:07 ` David Hildenbrand
@ 2020-03-27  9:10 ` Janosch Frank
  2 siblings, 0 replies; 5+ messages in thread
From: Janosch Frank @ 2020-03-27  9:10 UTC (permalink / raw)
  To: Christian Borntraeger, Janosch Frank
  Cc: KVM, David Hildenbrand, linux-s390, Cornelia Huck, Heiko Carstens


[-- Attachment #1.1: Type: text/plain, Size: 1330 bytes --]

On 3/27/20 9:56 AM, Christian Borntraeger wrote:
> If a signal is pending we might return -ENOMEM instead of -EINTR.
> We should propagate the proper error during KSM unsharing.
> 
> Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>

> ---
>  arch/s390/mm/gmap.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 27926a06df32..2bf63035a295 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2552,15 +2552,16 @@ int gmap_mark_unmergeable(void)
>  {
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
> +	int ret  = 0;
> 
>  	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> -		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
> -				MADV_UNMERGEABLE, &vma->vm_flags)) {
> -			return -ENOMEM;
> -		}
> +		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
> +				MADV_UNMERGEABLE, &vma->vm_flags);
> +		if (ret)
> +			return ret;
>  	}
>  	mm->def_flags &= ~VM_MERGEABLE;
> -	return 0;
> +	return ret;

That part is not really necessary but also doesn't hurt.

>  }
>  EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
> 



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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-03-27  9:10 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-03-27  8:56 [PATCH] s390/gmap: return proper error code on ksm unsharing Christian Borntraeger
2020-03-27  8:59 ` Julian Wiedmann
2020-03-27  9:07 ` David Hildenbrand
2020-03-27  9:08   ` Christian Borntraeger
2020-03-27  9:10 ` Janosch Frank

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