[PATCH v2 1/1] mm: move ->mremap() from file_operations to vm_operations_struct

[Oleg Nesterov]

vma->vm_ops->mremap() looks more natural and clean in move_vma(),
and this way ->mremap() can have more users. Say, vdso.

While at it, s/aio_ring_remap/aio_ring_mremap/.

Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
 fs/aio.c           |   25 ++++++++++++++++---------
 include/linux/fs.h |    1 -
 include/linux/mm.h |    1 +
 mm/mremap.c        |    4 ++--
 4 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 9bc1335..a632f14 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -308,15 +308,9 @@ 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 int aio_ring_remap(struct file *file, struct vm_area_struct *vma)
+static int aio_ring_mremap(struct vm_area_struct *vma)
 {
+       struct file *file = vma->vm_file;
        struct mm_struct *mm = vma->vm_mm;
        struct kioctx_table *table;
        int i, res = -EINVAL;
@@ -339,9 +333,22 @@ static int aio_ring_remap(struct file *file, struct 
vm_area_struct *vma)
        return res;
 }
 
+static const struct vm_operations_struct aio_ring_vm_ops = {
+       .mremap         = aio_ring_mremap,
+       .fault          = filemap_fault,
+       .map_pages      = filemap_map_pages,
+       .page_mkwrite   = filemap_page_mkwrite,
+};
+
+static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       vma->vm_flags |= VM_DONTEXPAND;
+       vma->vm_ops = &aio_ring_vm_ops;
+       return 0;
+}
+
 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 35ec87e..42aac09 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1582,7 +1582,6 @@ 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 *);
-       int (*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/include/linux/mm.h b/include/linux/mm.h
index a0fe3d3..0295b4a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -244,6 +244,7 @@ struct vm_fault {
 struct vm_operations_struct {
        void (*open)(struct vm_area_struct * area);
        void (*close)(struct vm_area_struct * area);
+       int (*mremap)(struct vm_area_struct * area);
        int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
        void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);
 
diff --git a/mm/mremap.c b/mm/mremap.c
index ed1b13a..aeba807 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -276,8 +276,8 @@ static unsigned long move_vma(struct vm_area_struct *vma,
                                     need_rmap_locks);
        if (moved_len < old_len) {
                err = -ENOMEM;
-       } else if (vma->vm_file && vma->vm_file->f_op->mremap) {
-               err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma);
+       } else if (vma->vm_ops && vma->vm_ops->mremap) {
+               err = vma->vm_ops->mremap(new_vma);
        }
 
        if (unlikely(err)) {
-- 
1.5.5.1


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