mm/mmap.c: pass in mapping to __vma_link_file()

__vma_link_file() resolves the mapping from the file, if there is one.
Pass through the mapping and check the vm_file externally since most
places already have the required information and check of vm_file.

Link: https://lkml.kernel.org/r/20220404143501.2016403-71-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index 287a6256ca5e2c86e40851d3d001f1511212a782..f3b8ee95811a8be528b1f0f65a043ce6d5113b00 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -457,21 +457,15 @@ static unsigned long count_vma_pages_range(struct mm_struct *mm,
        return nr_pages;
 }
 
-static void __vma_link_file(struct vm_area_struct *vma)
+static void __vma_link_file(struct vm_area_struct *vma,
+                           struct address_space *mapping)
 {
-       struct file *file;
-
-       file = vma->vm_file;
-       if (file) {
-               struct address_space *mapping = file->f_mapping;
-
-               if (vma->vm_flags & VM_SHARED)
-                       mapping_allow_writable(mapping);
+       if (vma->vm_flags & VM_SHARED)
+               mapping_allow_writable(mapping);
 
-               flush_dcache_mmap_lock(mapping);
-               vma_interval_tree_insert(vma, &mapping->i_mmap);
-               flush_dcache_mmap_unlock(mapping);
-       }
+       flush_dcache_mmap_lock(mapping);
+       vma_interval_tree_insert(vma, &mapping->i_mmap);
+       flush_dcache_mmap_unlock(mapping);
 }
 
 /*
@@ -514,10 +508,11 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
        }
 
        vma_store(mm, vma);
-       __vma_link_file(vma);
 
-       if (mapping)
+       if (mapping) {
+               __vma_link_file(vma, mapping);
                i_mmap_unlock_write(mapping);
+       }
 
        mm->map_count++;
        validate_mm(mm);
@@ -750,14 +745,14 @@ again:
                        uprobe_munmap(next, next->vm_start, next->vm_end);
 
                i_mmap_lock_write(mapping);
-               if (insert) {
+               if (insert && insert->vm_file) {
                        /*
                         * Put into interval tree now, so instantiated pages
                         * are visible to arm/parisc __flush_dcache_page
                         * throughout; but we cannot insert into address
                         * space until vma start or end is updated.
                         */
-                       __vma_link_file(insert);
+                       __vma_link_file(insert, insert->vm_file->f_mapping);
                }
        }
 
@@ -2959,6 +2954,7 @@ mas_store_fail:
 static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
                unsigned long addr, unsigned long len, unsigned long flags)
 {
+       struct address_space *mapping = NULL;
        struct mm_struct *mm = current->mm;
        validate_mm_mt(mm);
 
@@ -3014,13 +3010,15 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
        vma->vm_pgoff = addr >> PAGE_SHIFT;
        vma->vm_flags = flags;
        vma->vm_page_prot = vm_get_page_prot(flags);
-       if (vma->vm_file)
-               i_mmap_lock_write(vma->vm_file->f_mapping);
+       if (vma->vm_file) {
+               mapping = vma->vm_file->f_mapping;
+               i_mmap_lock_write(mapping);
+       }
        vma_mas_store(vma, mas);
        mm->map_count++;
-       if (vma->vm_file) {
-               __vma_link_file(vma);
-               i_mmap_unlock_write(vma->vm_file->f_mapping);
+       if (mapping) {
+               __vma_link_file(vma, mapping);
+               i_mmap_unlock_write(mapping);
        }
 
 out: