Hi Alasdair,

Thank you for the comments.

Alasdair G Kergon wrote:
> Make sure you test this properly under low memory situations.

OK.

> dm_swap_table() mustn't block waiting for memory to become
> free (except in a controlled way e.g. with a mempool, but
> it would need more than that here).
> 
> Here, dm_swap_table() leads to kmalloc() getting called
> in sysfs_add_link().

I moved the sysfs_add_link() to the last part of dm_resume().
Directory creation/deletion are also moved in the alloc_dev/
free_dev function as kobject_register/unregister may allocate
memory.
I didn't change the part of removing symlink as it doesn't
allocate memory.

Do you think this is an acceptable approach?

-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.