khugepaged: remove hpage from collapse_huge_page()

Work purely in terms of the folio.  Removes a call to compound_head()
in put_page().

Link: https://lkml.kernel.org/r/20240403171838.1445826-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 2f1dacd65d12b51ab9267e29c21a4c97f00a948e..1c99d18602e5c8df66c5c1aceffa03ab8821d3c7 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1082,7 +1082,6 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
        pte_t *pte;
        pgtable_t pgtable;
        struct folio *folio;
-       struct page *hpage;
        spinlock_t *pmd_ptl, *pte_ptl;
        int result = SCAN_FAIL;
        struct vm_area_struct *vma;
@@ -1099,7 +1098,6 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
        mmap_read_unlock(mm);
 
        result = alloc_charge_folio(&folio, mm, cc);
-       hpage = &folio->page;
        if (result != SCAN_SUCCEED)
                goto out_nolock;
 
@@ -1198,7 +1196,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
         */
        anon_vma_unlock_write(vma->anon_vma);
 
-       result = __collapse_huge_page_copy(pte, hpage, pmd, _pmd,
+       result = __collapse_huge_page_copy(pte, &folio->page, pmd, _pmd,
                                           vma, address, pte_ptl,
                                           &compound_pagelist);
        pte_unmap(pte);
@@ -1213,7 +1211,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
        __folio_mark_uptodate(folio);
        pgtable = pmd_pgtable(_pmd);
 
-       _pmd = mk_huge_pmd(hpage, vma->vm_page_prot);
+       _pmd = mk_huge_pmd(&folio->page, vma->vm_page_prot);
        _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
 
        spin_lock(pmd_ptl);
@@ -1225,14 +1223,14 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
        update_mmu_cache_pmd(vma, address, pmd);
        spin_unlock(pmd_ptl);
 
-       hpage = NULL;
+       folio = NULL;
 
        result = SCAN_SUCCEED;
 out_up_write:
        mmap_write_unlock(mm);
 out_nolock:
-       if (hpage)
-               put_page(hpage);
+       if (folio)
+               folio_put(folio);
        trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result);
        return result;
 }