From 0cb8fd4d14165a7e654048e43983d86f75b90879 Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Thu, 8 Jun 2023 18:08:20 -0700
Subject: mm/migrate: remove cruft from migration_entry_wait()s
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migration_entry_wait_on_locked() does not need to take a mapped pte
pointer, its callers can do the unmap first.  Annotate it with
__releases(ptl) to reduce sparse warnings.

Fold __migration_entry_wait_huge() into migration_entry_wait_huge().  Fold
__migration_entry_wait() into migration_entry_wait(), preferring the
tighter pte_offset_map_lock() to pte_offset_map() and pte_lockptr().

Link: https://lkml.kernel.org/r/b0e2a532-cdf2-561b-e999-f3b13b8d6d3@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/filemap.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

(limited to 'mm/filemap.c')

diff --git a/mm/filemap.c b/mm/filemap.c
index 916b7c6444fe..e0259fb823a5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1362,8 +1362,6 @@ repeat:
 /**
  * migration_entry_wait_on_locked - Wait for a migration entry to be removed
  * @entry: migration swap entry.
- * @ptep: mapped pte pointer. Will return with the ptep unmapped. Only required
- *        for pte entries, pass NULL for pmd entries.
  * @ptl: already locked ptl. This function will drop the lock.
  *
  * Wait for a migration entry referencing the given page to be removed. This is
@@ -1372,13 +1370,13 @@ repeat:
  * should be called while holding the ptl for the migration entry referencing
  * the page.
  *
- * Returns after unmapping and unlocking the pte/ptl with pte_unmap_unlock().
+ * Returns after unlocking the ptl.
  *
  * This follows the same logic as folio_wait_bit_common() so see the comments
  * there.
  */
-void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
-				spinlock_t *ptl)
+void migration_entry_wait_on_locked(swp_entry_t entry, spinlock_t *ptl)
+	__releases(ptl)
 {
 	struct wait_page_queue wait_page;
 	wait_queue_entry_t *wait = &wait_page.wait;
@@ -1412,10 +1410,7 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
 	 * a valid reference to the page, and it must take the ptl to remove the
 	 * migration entry. So the page is valid until the ptl is dropped.
 	 */
-	if (ptep)
-		pte_unmap_unlock(ptep, ptl);
-	else
-		spin_unlock(ptl);
+	spin_unlock(ptl);
 
 	for (;;) {
 		unsigned int flags;
-- 
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