Re: [PATCH 1/2] mm: fixup_userfault returns VM_FAULT_RETRY if asked

From	"Kirill A. Shutemov" <kirill@shutemov.name>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] mm: fixup_userfault returns VM_FAULT_RETRY if asked
Date	2015-11-19 01:20 +0100
Message-ID	<qwl7c-1Xq-33@gated-at.bofh.it> (permalink)
References	<qwkNQ-1An-7@gated-at.bofh.it> <qwkNQ-1An-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Nov 19, 2015 at 12:49:57AM +0100, Dominik Dingel wrote:
> When calling fixup_userfault with FAULT_FLAG_ALLOW_RETRY, fixup_userfault
> didn't care about VM_FAULT_RETRY and returned 0. If the VM_FAULT_RETRY flag is
> set we will return the complete result of handle_mm_fault.
> 
> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
> ---
>  mm/gup.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index deafa2c..2af3b31 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -609,6 +609,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
>  			return -EFAULT;
>  		BUG();
>  	}
> +	if (ret & VM_FAULT_RETRY)
> +		return ret;

Nope. fixup_user_fault() return errno, not VM_FAULT_* mask.

I guess it should be
		return -EBUSY;

>  	if (tsk) {
>  		if (ret & VM_FAULT_MAJOR)
>  			tsk->maj_flt++;
> -- 
> 2.3.9
> 

-- 
 Kirill A. Shutemov
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[PATCH 1/2] mm: fixup_userfault returns VM_FAULT_RETRY if asked Dominik Dingel <dingel@linux.vnet.ibm.com> - 2015-11-19 01:00 +0100
  Re: [PATCH 1/2] mm: fixup_userfault returns VM_FAULT_RETRY if asked "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-11-19 01:20 +0100

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