mm/pgtable: define pte_index so that preprocessor could recognize it

stable inclusion
from stable-v5.10.99
commit 7053188ddba3f6e7402000c94496066fa700891e
bugzilla: https://gitee.com/openeuler/kernel/issues/I55O7H

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7053188ddba3f6e7402000c94496066fa700891e

--------------------------------

commit 314c459a upstream.

Since commit 974b9b2c ("mm: consolidate pte_index() and
pte_offset_*() definitions") pte_index is a static inline and there is
no define for it that can be recognized by the preprocessor.  As a
result, vm_insert_pages() uses slower loop over vm_insert_page() instead
of insert_pages() that amortizes the cost of spinlock operations when
inserting multiple pages.

Link: https://lkml.kernel.org/r/20220111145457.20748-1-rppt@kernel.org
Fixes: 974b9b2c ("mm: consolidate pte_index() and pte_offset_*() definitions")
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Reported-by: NChristian Dietrich <stettberger@dokucode.de>
Reviewed-by: NKhalid Aziz <khalid.aziz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/pgtable.h

@@ -44,6 +44,7 @@ static inline unsigned long pte_index(unsigned long address)
 {
 	return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
 }
+#define pte_index pte_index
 
 #ifndef pmd_index
 static inline unsigned long pmd_index(unsigned long address)