Revert "mm: introduce a new page type for page pool in page type"

This reverts commit db359fccf212 ("mm: introduce a new page type for page
pool in page type") and a part of 735a309b4bfb9e ("net: add net_iov_init()
and use it to initialize ->page_type").

Netpp page_type'ed pages might be used in mapping so as to use @_mapcount.
However, since @page_type and @_mapcount are union'ed in struct page,
these two can't be used at the same time.  Revert the commit introducing
page_type for Netpp for now.

The patch will be retried once @page_type and @_mapcount get allowed to be
used at the same time.

The revert also includes removal of @page_type initialization part
introduced by commit 735a309b4bfb9e ("net: add net_iov_init() and use it
to initialize ->page_type"), which will be restored on the retry.

Link: https://lore.kernel.org/20260515034701.17027-1-byungchul@sk.com
Fixes: db359fccf212 ("mm: introduce a new page type for page pool in page type")
Signed-off-by: Byungchul Park <byungchul@sk.com>
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Closes: https://lore.kernel.org/all/982b9bc1-0a0a-4fc5-8e3a-3672db2b29a1@nvidia.com
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Mark Bloch <mbloch@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tariq Toukan <tariqt@nvidia.com>
Cc: Toke Hoiland-Jorgensen <toke@redhat.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 17 deletions

diff --git a/include/net/netmem.h b/include/net/netmem.h
index 78fe51e5756b..bccacd21b6c3 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -94,20 +94,10 @@ enum net_iov_type {
  */
 struct net_iov {
 	struct netmem_desc desc;
-	unsigned int page_type;
 	enum net_iov_type type;
 	struct net_iov_area *owner;
 };
 
-/* Make sure 'the offset of page_type in struct page == the offset of
- * type in struct net_iov'.
- */
-#define NET_IOV_ASSERT_OFFSET(pg, iov)			\
-	static_assert(offsetof(struct page, pg) ==	\
-		      offsetof(struct net_iov, iov))
-NET_IOV_ASSERT_OFFSET(page_type, page_type);
-#undef NET_IOV_ASSERT_OFFSET
-
 struct net_iov_area {
 	/* Array of net_iovs for this area. */
 	struct net_iov *niovs;
@@ -127,11 +117,7 @@ static inline unsigned int net_iov_idx(const struct net_iov *niov)
 	return niov - net_iov_owner(niov)->niovs;
 }
 
-/* Initialize a niov: stamp the owning area, the memory provider type,
- * and the page_type "no type" sentinel expected by the page-type API
- * (see PAGE_TYPE_OPS in <linux/page-flags.h>) so that
- * page_pool_set_pp_info() can later call __SetPageNetpp() on a niov
- * cast to struct page.
+/* Initialize a niov: stamp the owning area, the memory provider type.
  */
 static inline void net_iov_init(struct net_iov *niov,
 				struct net_iov_area *owner,
@@ -139,7 +125,6 @@ static inline void net_iov_init(struct net_iov *niov,
 {
 	niov->owner = owner;
 	niov->type = type;
-	niov->page_type = UINT_MAX;
 }
 
 /* netmem */
@@ -245,7 +230,7 @@ static inline unsigned long netmem_pfn_trace(netmem_ref netmem)
  */
 #define pp_page_to_nmdesc(p)						\
 ({									\
-	DEBUG_NET_WARN_ON_ONCE(!PageNetpp(p));				\
+	DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p));		\
 	__pp_page_to_nmdesc(p);						\
 })