mm: add the "struct mm_struct *mm" local into

Cosmetic, but expand_upwards() and expand_downwards() overuse vma->vm_mm,
a local variable makes sense imho.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index d1ac224..3204a7e 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2148,6 +2148,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
  */
 int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 {
+       struct mm_struct *mm = vma->vm_mm;
        int error;
 
        if (!(vma->vm_flags & VM_GROWSUP))
@@ -2197,10 +2198,10 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                                 * So, we reuse mm->page_table_lock to guard
                                 * against concurrent vma expansions.
                                 */
-                               spin_lock(&vma->vm_mm->page_table_lock);
+                               spin_lock(&mm->page_table_lock);
                                if (vma->vm_flags & VM_LOCKED)
-                                       vma->vm_mm->locked_vm += grow;
-                               vm_stat_account(vma->vm_mm, vma->vm_flags,
+                                       mm->locked_vm += grow;
+                               vm_stat_account(mm, vma->vm_flags,
                                                vma->vm_file, grow);
                                anon_vma_interval_tree_pre_update_vma(vma);
                                vma->vm_end = address;
@@ -2208,8 +2209,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                                if (vma->vm_next)
                                        vma_gap_update(vma->vm_next);
                                else
-                                       vma->vm_mm->highest_vm_end = address;
-                               spin_unlock(&vma->vm_mm->page_table_lock);
+                                       mm->highest_vm_end = address;
+                               spin_unlock(&mm->page_table_lock);
 
                                perf_event_mmap(vma);
                        }
@@ -2217,7 +2218,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
        }
        vma_unlock_anon_vma(vma);
        khugepaged_enter_vma_merge(vma, vma->vm_flags);
-       validate_mm(vma->vm_mm);
+       validate_mm(mm);
        return error;
 }
 #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
@@ -2228,6 +2229,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 int expand_downwards(struct vm_area_struct *vma,
                                   unsigned long address)
 {
+       struct mm_struct *mm = vma->vm_mm;
        int error;
 
        /*
@@ -2272,17 +2274,17 @@ int expand_downwards(struct vm_area_struct *vma,
                                 * So, we reuse mm->page_table_lock to guard
                                 * against concurrent vma expansions.
                                 */
-                               spin_lock(&vma->vm_mm->page_table_lock);
+                               spin_lock(&mm->page_table_lock);
                                if (vma->vm_flags & VM_LOCKED)
-                                       vma->vm_mm->locked_vm += grow;
-                               vm_stat_account(vma->vm_mm, vma->vm_flags,
+                                       mm->locked_vm += grow;
+                               vm_stat_account(mm, vma->vm_flags,
                                                vma->vm_file, grow);
                                anon_vma_interval_tree_pre_update_vma(vma);
                                vma->vm_start = address;
                                vma->vm_pgoff -= grow;
                                anon_vma_interval_tree_post_update_vma(vma);
                                vma_gap_update(vma);
-                               spin_unlock(&vma->vm_mm->page_table_lock);
+                               spin_unlock(&mm->page_table_lock);
 
                                perf_event_mmap(vma);
                        }
@@ -2290,7 +2292,7 @@ int expand_downwards(struct vm_area_struct *vma,
        }
        vma_unlock_anon_vma(vma);
        khugepaged_enter_vma_merge(vma, vma->vm_flags);
-       validate_mm(vma->vm_mm);
+       validate_mm(mm);
        return error;
 }