Re: [PATCH V4 5/5] arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade

On Thu, Dec 20, 2018 at 11:30:12AM +1100, Benjamin Herrenschmidt wrote:

On Wed, 2018-12-19 at 08:50 +0530, Aneesh Kumar K.V wrote:

quoted

Christoph Hellwig [off-list ref] writes:

quoted

On Tue, Dec 18, 2018 at 03:11:37PM +0530, Aneesh Kumar K.V wrote:

quoted

+EXPORT_SYMBOL(huge_ptep_modify_prot_start);

The only user of this function is the one you added in the last patch
in mm/hugetlb.c, so there is no need to export this function.

quoted

+
+void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
+				  pte_t *ptep, pte_t old_pte, pte_t pte)
+{
+
+	if (radix_enabled())
+		return radix__huge_ptep_modify_prot_commit(vma, addr, ptep,
+							   old_pte, pte);
+	set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+}
+EXPORT_SYMBOL(huge_ptep_modify_prot_commit);

Same here.

That was done considering that ptep_modify_prot_start/commit was defined
in asm-generic/pgtable.h. I was trying to make sure I didn't break
anything with the patch. Also s390 do have that EXPORT_SYMBOL() for the
same. hugetlb just inherited that.

If you feel strongly about it, I can drop the EXPORT_SYMBOL().

At the very least it should be _GPL

In general yes, but in this case it just needs to go.  The s390
maintainers already removed a patch to remove their
ptep_modify_prot_start / ptep_modify_prot_commit exports.