3 files changed, 28 insertions, 1 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 14b93159ef83..bfab55607a4d 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -286,12 +286,37 @@ static void aio_free_ring(struct kioctx *ctx)
 
 static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
 {
+        vma->vm_flags |= VM_DONTEXPAND;
         vma->vm_ops = &generic_file_vm_ops;
         return 0;
 }
 
+static void aio_ring_remap(struct file *file, struct vm_area_struct *vma)
+{
+        struct mm_struct *mm = vma->vm_mm;
+        struct kioctx_table *table;
+        int i;
+
+        spin_lock(&mm->ioctx_lock);
+        rcu_read_lock();
+        table = rcu_dereference(mm->ioctx_table);
+        for (i = 0; i < table->nr; i++) {
+                struct kioctx *ctx;
+
+                ctx = table->table[i];
+                if (ctx && ctx->aio_ring_file == file) {
+                        ctx->user_id = ctx->mmap_base = vma->vm_start;
+                        break;
+                }
+        }
+
+        rcu_read_unlock();
+        spin_unlock(&mm->ioctx_lock);
+}
+
 static const struct file_operations aio_ring_fops = {
         .mmap = aio_ring_mmap,
+        .mremap = aio_ring_remap,
 };
 
 #if IS_ENABLED(CONFIG_MIGRATION)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9ab779e8a63c..85f378c55c26 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1497,6 +1497,7 @@ struct file_operations {
         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
         int (*mmap) (struct file *, struct vm_area_struct *);
+        void (*mremap)(struct file *, struct vm_area_struct *);
         int (*open) (struct inode *, struct file *);
         int (*flush) (struct file *, fl_owner_t id);
         int (*release) (struct inode *, struct file *);
diff --git a/mm/mremap.c b/mm/mremap.c
index b147f66f4c40..c855922497a3 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -288,7 +288,8 @@ static unsigned long move_vma(struct vm_area_struct *vma,
                 old_len = new_len;
                 old_addr = new_addr;
                 new_addr = -ENOMEM;
-        }
+        } else if (vma->vm_file && vma->vm_file->f_op->mremap)
+                vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
 
         /* Conceal VM_ACCOUNT so old reservation is not undone */
         if (vm_flags & VM_ACCOUNT) {