Re: [RFC 07/15] PM / Hibernate: add sws_modules_ops

Rafael J. Wysocki
2010-03-25T22:02:53Z

On Tuesday 23 March 2010, Jiri Slaby wrote:
> For now they will only hold swap operations. In next patches, user
> support will be converted to ops as well to have a single layer and
> can push pages instead of pulling them.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Nigel Cunningham <ncunningham@crca.org.au>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> ---
> kernel/power/hibernate.c | 2 +
> kernel/power/power.h | 13 +++++++++++
> kernel/power/swap.c | 51 ++++++++++++++++++++++++++++++---------------
> 3 files changed, 49 insertions(+), 17 deletions(-)
>
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index da5288e..762431e 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -34,6 +34,8 @@ dev_t swsusp_resume_device;
> sector_t swsusp_resume_block;
> int in_suspend __nosavedata = 0;
>
> +struct sws_module_ops *sws_io_ops;
> +
> enum {
> HIBERNATION_INVALID,
> HIBERNATION_PLATFORM,
> diff --git a/kernel/power/power.h b/kernel/power/power.h
> index 6c4b4fa..0f08de4 100644
> --- a/kernel/power/power.h
> +++ b/kernel/power/power.h
> @@ -115,6 +115,17 @@ struct snapshot_handle {
> */
> #define data_of(handle) ((handle).buffer)
>
> +struct sws_module_ops {

I'd call that hibernate_io_ops FWIW.

> + unsigned long (*storage_available)(void);

free_space() ?

> +
> + int (*get_reader)(unsigned int *flags_p);
> + int (*put_reader)(void);
> + int (*get_writer)(void);
> + int (*put_writer)(unsigned int flags, int error);

I agree with Pavel that these names are not exactly self-documenting.

Would it make sense to use names like reader_start(), reader_finish() and
similarly for "writer"?

> + int (*read_page)(void *addr, struct bio **bio_chain);
> + int (*write_page)(void *addr, struct bio **bio_chain);

Also one might think of adding a data pointer to this structure that will
be passed to the callbacks. This way it would be easier to think of our
storage spaces as objects, each with a set of methods and a pointer to
the data they operate on.

Rafael