Message-Id: <200510261844.j9QIiqg22461@unix-os.sc.intel.com>
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'David Gibson'" <david@gibson.dropbear.id.au>,
       "Adam Litke" <agl@us.ibm.com>, <linux-mm@kvack.org>,
       <linux-kernel@vger.kernel.org>, <hugh@veritas.com>,
       "William Irwin" <wli@holomorphy.com>
Subject: RE: RFC: Cleanup / small fixes to hugetlb fault handling
Date: Wed, 26 Oct 2005 11:44:52 -0700
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David Gibson wrote on Tuesday, October 25, 2005 7:49 PM
> +int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> +		  unsigned long address, int write_access)
> +{
> +	pte_t *ptep;
> +	pte_t entry;
> +
> +	ptep = huge_pte_alloc(mm, address);
> +	if (! ptep)
> +		/* OOM */
> +		return VM_FAULT_SIGBUS;
> +
> +	entry = *ptep;
> +
> +	if (pte_none(entry))
> +		return hugetlb_no_page(mm, vma, address, ptep);
> +
> +	/* we could get here if another thread instantiated the pte
> +	 * before the test above */
> +
> +	return VM_FAULT_SIGBUS;
>  }

Are you sure about the last return?  Looks like a typo to me, if *ptep
is present, it should return VM_FAULT_MINOR.

But the bigger question is: don't you need some lock when checking *ptep?

- Ken

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