mm/memory: convert wp_page_shared() to use folios

Saves six implicit calls to compound_head().

Link: https://lkml.kernel.org/r/20230706163847.403202-2-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 5209f3d..a88e57d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3283,13 +3283,13 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
        return 0;
 }
 
-static vm_fault_t wp_page_shared(struct vm_fault *vmf)
+static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
        __releases(vmf->ptl)
 {
        struct vm_area_struct *vma = vmf->vma;
        vm_fault_t ret = 0;
 
-       get_page(vmf->page);
+       folio_get(folio);
 
        if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
                vm_fault_t tmp;
@@ -3298,21 +3298,21 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf)
                tmp = do_page_mkwrite(vmf);
                if (unlikely(!tmp || (tmp &
                                      (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
-                       put_page(vmf->page);
+                       folio_put(folio);
                        return tmp;
                }
                tmp = finish_mkwrite_fault(vmf);
                if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
-                       unlock_page(vmf->page);
-                       put_page(vmf->page);
+                       folio_unlock(folio);
+                       folio_put(folio);
                        return tmp;
                }
        } else {
                wp_page_reuse(vmf);
-               lock_page(vmf->page);
+               folio_lock(folio);
        }
        ret |= fault_dirty_shared_page(vmf);
-       put_page(vmf->page);
+       folio_put(folio);
 
        return ret;
 }
@@ -3363,6 +3363,9 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
 
        vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte);
 
+       if (vmf->page)
+               folio = page_folio(vmf->page);
+
        /*
         * Shared mapping: we are guaranteed to have VM_WRITE and
         * FAULT_FLAG_WRITE set at this point.
@@ -3377,12 +3380,9 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
                 */
                if (!vmf->page)
                        return wp_pfn_shared(vmf);
-               return wp_page_shared(vmf);
+               return wp_page_shared(vmf, folio);
        }
 
-       if (vmf->page)
-               folio = page_folio(vmf->page);
-
        /*
         * Private mapping: create an exclusive anonymous page copy if reuse
         * is impossible. We might miss VM_WRITE for FOLL_FORCE handling.