[PATCH 6.1 010/236] mm: add private field of first tail to struct page and struct folio

Greg Kroah-Hartman
2024-05-14T11:27:47Z

From: Sidhartha Kumar <sidhartha.kumar@oracle.com>

[ Upstream commit d340625f4849ab5dbfebbc7d84709fbfcd39e52f ]

Allow struct folio to store hugetlb metadata that is contained in the
private field of the first tail page. On 32-bit, _private_1 aligns with
page[1].private.

Link: https://lkml.kernel.org/r/20220922154207.1575343-3-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Colin Cross <ccross@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: b76b46902c2d ("mm/hugetlb: fix missing hugetlb_lock for resv uncharge")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/mm_types.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 247aedb18d5c3..a9c1d611029d1 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -144,6 +144,7 @@ struct page {
atomic_t compound_pincount;
#ifdef CONFIG_64BIT
unsigned int compound_nr; /* 1 << compound_order */
+ unsigned long _private_1;
#endif
};
struct { /* Second tail page of compound page */
@@ -264,6 +265,7 @@ struct page {
* @_total_mapcount: Do not use directly, call folio_entire_mapcount().
* @_pincount: Do not use directly, call folio_maybe_dma_pinned().
* @_folio_nr_pages: Do not use directly, call folio_nr_pages().
+ * @_private_1: Do not use directly, call folio_get_private_1().
*
* A folio is a physically, virtually and logically contiguous set
* of bytes. It is a power-of-two in size, and it is aligned to that
@@ -311,6 +313,7 @@ struct folio {
#ifdef CONFIG_64BIT
unsigned int _folio_nr_pages;
#endif
+ unsigned long _private_1;
};

#define FOLIO_MATCH(pg, fl) \
@@ -338,6 +341,7 @@ FOLIO_MATCH(compound_mapcount, _total_mapcount);
FOLIO_MATCH(compound_pincount, _pincount);
#ifdef CONFIG_64BIT
FOLIO_MATCH(compound_nr, _folio_nr_pages);
+FOLIO_MATCH(_private_1, _private_1);
#endif
#undef FOLIO_MATCH

@@ -383,6 +387,16 @@ static inline void *folio_get_private(struct folio *folio)
return folio->private;
}

+static inline void folio_set_private_1(struct folio *folio, unsigned long private)
+{
+ folio->_private_1 = private;
+}
+
+static inline unsigned long folio_get_private_1(struct folio *folio)
+{
+ return folio->_private_1;
+}
+
struct page_frag_cache {
void * va;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
--
2.43.0