mm: use single SWP_DEVICE_EXCLUSIVE entry type

There is no need for the distinction anymore; let's merge the readable and
writable device-exclusive entries into a single device-exclusive entry
type.

Link: https://lkml.kernel.org/r/20250210193801.781278-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: Alistair Popple <apopple@nvidia.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Lyude <lyude@redhat.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yanteng Si <si.yanteng@linux.dev>
Cc: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 7 insertions, 27 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 91b30701274e..9a48e79a0a52 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -74,14 +74,13 @@ static inline int current_is_kswapd(void)
  * to a special SWP_DEVICE_{READ|WRITE} entry.
  *
  * When a page is mapped by the device for exclusive access we set the CPU page
- * table entries to special SWP_DEVICE_EXCLUSIVE_* entries.
+ * table entries to a special SWP_DEVICE_EXCLUSIVE entry.
  */
 #ifdef CONFIG_DEVICE_PRIVATE
-#define SWP_DEVICE_NUM 4
+#define SWP_DEVICE_NUM 3
 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM)
 #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1)
-#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
-#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3)
+#define SWP_DEVICE_EXCLUSIVE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2)
 #else
 #define SWP_DEVICE_NUM 0
 #endif
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 96f26e29fefe..64ea151a7ae3 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -186,26 +186,16 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry)
 	return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
 }
 
-static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
+static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
 {
-	return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
-}
-
-static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
-{
-	return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
+	return swp_entry(SWP_DEVICE_EXCLUSIVE, offset);
 }
 
 static inline bool is_device_exclusive_entry(swp_entry_t entry)
 {
-	return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
-		swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
+	return swp_type(entry) == SWP_DEVICE_EXCLUSIVE;
 }
 
-static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
-{
-	return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
-}
 #else /* CONFIG_DEVICE_PRIVATE */
 static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
 {
@@ -227,12 +217,7 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry)
 	return false;
 }
 
-static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
-{
-	return swp_entry(0, 0);
-}
-
-static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
+static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
 {
 	return swp_entry(0, 0);
 }
@@ -242,10 +227,6 @@ static inline bool is_device_exclusive_entry(swp_entry_t entry)
 	return false;
 }
 
-static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
-{
-	return false;
-}
 #endif /* CONFIG_DEVICE_PRIVATE */
 
 #ifdef CONFIG_MIGRATION