[PATCH] mm: Export PageHeadHuge()

[PATCH] mm: Export PageHeadHuge()

[David Howells]

Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
folio_file_page() and folio_contains().

Signed-off-by: David Howells <dhowells@redhat.com>
---

 mm/hugetlb.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 68eead0259cc..ad6ef6d2c0bc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1717,6 +1717,7 @@ int PageHeadHuge(struct page *page_head)
 
 	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
 }
+EXPORT_SYMBOL(PageHeadHuge);
 
 /*
  * Find and lock address space (mapping) in write mode.

Re: [PATCH] mm: Export PageHeadHuge()

[Christoph Hellwig]

On Fri, Aug 20, 2021 at 05:14:47PM +0100, David Howells wrote:
> Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
> folio_file_page() and folio_contains().

.. none of which are used in modular code in linux-next.

Re: [PATCH] mm: Export PageHeadHuge()

[Christoph Hellwig]

On Mon, Feb 28, 2022 at 01:22:56PM +0000, David Howells wrote:
>     
> Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
> such as folio_file_page() and folio_contains().  Matthew suggested I use
> the first of those instead of doing the same calculation manually - but
> I can't call it from a module.
> 
> Kirill suggested rearranging things to put it in a header, but that
> introduces header dependencies because of where constants are defined.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: willy@infradead.org
> Link: https://lore.kernel.org/r/163707085314.3221130.14783857863702203440.stgit@warthog.procyon.org.uk/
> 
> ---
>  mm/hugetlb.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 61895cc01d09..5768df43b05c 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1854,6 +1854,7 @@ int PageHeadHuge(struct page *page_head)
>  
>  	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
>  }
> +EXPORT_SYMBOL(PageHeadHuge);

EXPORT_SYMBOL_GPL for anything hugepage related, please.

[PATCH] mm: Export PageHeadHuge()

[David Howells]

    
Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
such as folio_file_page() and folio_contains().  Matthew suggested I use
the first of those instead of doing the same calculation manually - but
I can't call it from a module.

Kirill suggested rearranging things to put it in a header, but that
introduces header dependencies because of where constants are defined.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: willy@infradead.org
Link: https://lore.kernel.org/r/163707085314.3221130.14783857863702203440.stgit@warthog.procyon.org.uk/

---
 mm/hugetlb.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 61895cc01d09..5768df43b05c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1854,6 +1854,7 @@ int PageHeadHuge(struct page *page_head)
 
 	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
 }
+EXPORT_SYMBOL(PageHeadHuge);
 
 /*
  * Find and lock address space (mapping) in write mode.

Re: [PATCH] mm: Export PageHeadHuge()

[Kirill A. Shutemov]

On Wed, Nov 17, 2021 at 01:20:02PM +0000, Matthew Wilcox wrote:
> On Wed, Nov 17, 2021 at 11:36:23AM +0300, Kirill A. Shutemov wrote:
> > On Tue, Nov 16, 2021 at 01:54:13PM +0000, David Howells wrote:
> > > Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
> > > folio_file_page() and folio_contains().
> > 
> > Maybe move it to page-flag.h instead? It is trivial enough.
> 
> HUGETLB_PAGE_DTOR is defined in mm.h so there's a bit of a dependency
> problem there.

Move enum compound_dtor_id to mm_types.h?

-- 
 Kirill A. Shutemov

Re: [PATCH] mm: Export PageHeadHuge()

[Matthew Wilcox]

On Wed, Nov 17, 2021 at 11:36:23AM +0300, Kirill A. Shutemov wrote:
> On Tue, Nov 16, 2021 at 01:54:13PM +0000, David Howells wrote:
> > Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
> > folio_file_page() and folio_contains().
> 
> Maybe move it to page-flag.h instead? It is trivial enough.

HUGETLB_PAGE_DTOR is defined in mm.h so there's a bit of a dependency
problem there.

Re: [PATCH] mm: Export PageHeadHuge()

[Kirill A. Shutemov]

On Tue, Nov 16, 2021 at 01:54:13PM +0000, David Howells wrote:
> Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
> folio_file_page() and folio_contains().

Maybe move it to page-flag.h instead? It is trivial enough.

-- 
 Kirill A. Shutemov

[PATCH] mm: Export PageHeadHuge()

[David Howells]

Export PageHeadHuge() - it's used by folio_test_hugetlb() and thence by
folio_file_page() and folio_contains().

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-mm@kvack.org
---

 mm/hugetlb.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e09159c957e3..16f2e5d5f1a9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1852,6 +1852,7 @@ int PageHeadHuge(struct page *page_head)
 
 	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
 }
+EXPORT_SYMBOL(PageHeadHuge);
 
 /*
  * Find and lock address space (mapping) in write mode.