mm/migration: remove unneeded local variable mapping_locked

Patch series "A few cleanup and fixup patches for migration", v2.

This series contains a few patches to remove unneeded variables, jump
label and use helper to simplify the code.  Also we fix some bugs such as
page refcounts leak , invalid node access and so on.  More details can be
found in the respective changelogs.

This patch (of 11):

When mapping_locked is true, TTU_RMAP_LOCKED is always set to ttu.  We can
check ttu instead so mapping_locked can be removed.  And ttu is either 0
or TTU_RMAP_LOCKED now.  Change '|=' to '=' to reflect this.

Link: https://lkml.kernel.org/r/20220318111709.60311-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220318111709.60311-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index d298544940b89f21eddad966cd5596cec867450a..7d698caf333fb812c2502aa4b6bc07dbc3a245fe 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1230,7 +1230,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
                goto put_anon;
 
        if (page_mapped(hpage)) {
-               bool mapping_locked = false;
                enum ttu_flags ttu = 0;
 
                if (!PageAnon(hpage)) {
@@ -1244,14 +1243,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
                        if (unlikely(!mapping))
                                goto unlock_put_anon;
 
-                       mapping_locked = true;
-                       ttu |= TTU_RMAP_LOCKED;
+                       ttu = TTU_RMAP_LOCKED;
                }
 
                try_to_migrate(src, ttu);
                page_was_mapped = 1;
 
-               if (mapping_locked)
+               if (ttu & TTU_RMAP_LOCKED)
                        i_mmap_unlock_write(mapping);
        }