page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
going to use page_keyid() and since KVM can be built as a module
lookup_page_ext() has to be exported.
Signed-off-by: Kirill A. Shutemov <[email protected]>
---
mm/page_ext.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/page_ext.c b/mm/page_ext.c
index 1af8b82087f2..91e4e87f6e41 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -142,6 +142,7 @@ struct page_ext *lookup_page_ext(const struct page *page)
MAX_ORDER_NR_PAGES);
return get_entry(base, index);
}
+EXPORT_SYMBOL_GPL(lookup_page_ext);
static int __init alloc_node_page_ext(int nid)
{
@@ -212,6 +213,7 @@ struct page_ext *lookup_page_ext(const struct page *page)
return NULL;
return get_entry(section->page_ext, pfn);
}
+EXPORT_SYMBOL_GPL(lookup_page_ext);
static void *__meminit alloc_page_ext(size_t size, int nid)
{
--
2.20.1
On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote:
> page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
> going to use page_keyid() and since KVM can be built as a module
> lookup_page_ext() has to be exported.
I _really_ hate having to export world+dog for KVM. This one might not
be a real issue, but I itch every time I see an export for KVM these
days.
On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote:
> On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote:
> > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
> > going to use page_keyid() and since KVM can be built as a module
> > lookup_page_ext() has to be exported.
>
> I _really_ hate having to export world+dog for KVM. This one might not
> be a real issue, but I itch every time I see an export for KVM these
> days.
Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P
--
Kirill A. Shutemov
On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote:
> On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote:
> > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote:
> > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
> > > going to use page_keyid() and since KVM can be built as a module
> > > lookup_page_ext() has to be exported.
> >
> > I _really_ hate having to export world+dog for KVM. This one might not
> > be a real issue, but I itch every time I see an export for KVM these
> > days.
>
> Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P
Or disallow KVM (or parts thereof) from being a module anymore.
On Mon, 2019-06-17 at 11:30 +0200, Peter Zijlstra wrote:
> On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote:
> > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote:
> > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote:
> > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
> > > > going to use page_keyid() and since KVM can be built as a module
> > > > lookup_page_ext() has to be exported.
> > >
> > > I _really_ hate having to export world+dog for KVM. This one might not
> > > be a real issue, but I itch every time I see an export for KVM these
> > > days.
> >
> > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P
>
> Or disallow KVM (or parts thereof) from being a module anymore.
For this particular symbol expose, I don't think its fair to blame KVM since the fundamental reason
is because page_keyid() (which calls lookup_page_ext()) being implemented as static inline function
in header file, so essentially having any other module who calls page_keyid() will trigger this
problem -- in fact IOMMU driver calls page_keyid() too so even w/o KVM lookup_page_ext() needs to be
exposed.
Thanks,
-Kai
On Mon, 2019-06-17 at 23:01 +1200, Kai Huang wrote:
> On Mon, 2019-06-17 at 11:30 +0200, Peter Zijlstra wrote:
> > On Sat, Jun 15, 2019 at 01:44:43AM +0300, Kirill A. Shutemov wrote:
> > > On Fri, Jun 14, 2019 at 01:12:59PM +0200, Peter Zijlstra wrote:
> > > > On Wed, May 08, 2019 at 05:43:40PM +0300, Kirill A. Shutemov wrote:
> > > > > page_keyid() is inline funcation that uses lookup_page_ext(). KVM is
> > > > > going to use page_keyid() and since KVM can be built as a module
> > > > > lookup_page_ext() has to be exported.
> > > >
> > > > I _really_ hate having to export world+dog for KVM. This one might not
> > > > be a real issue, but I itch every time I see an export for KVM these
> > > > days.
> > >
> > > Is there any better way? Do we need to invent EXPORT_SYMBOL_KVM()? :P
> >
> > Or disallow KVM (or parts thereof) from being a module anymore.
>
> For this particular symbol expose, I don't think its fair to blame KVM since the fundamental
> reason
> is because page_keyid() (which calls lookup_page_ext()) being implemented as static inline
> function
> in header file, so essentially having any other module who calls page_keyid() will trigger this
> problem -- in fact IOMMU driver calls page_keyid() too so even w/o KVM lookup_page_ext() needs to
> be
> exposed.
Oops it seems Intel IOMMU driver is not a module but buildin so yes KVM is the only module who calls
page_keyid() now. Sorry my bad. But if there's any other module calls page_keyid(), this patch is
required.
Thanks,
-Kai
>
> Thanks,
> -Kai
>