Re: [RFC 15/15] PM / Hibernate: move non-swap code to snapshot.c

[Rafael J. Wysocki]

On Tuesday 23 March 2010, Jiri Slaby wrote:
> Now, when all the swap-independent code was separated, it's time to
> move it into snapshot.c, because it is snapshot related.
> 
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> Cc: Nigel Cunningham <ncunningham@xxxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>

Quite frankly, I'd keep memory management in snapshot.c and move this stuff
to a separate file.

I have a plan to move snapshot.c to mm (perhaps under a different name) in
future, so that the mm people don't overlook it when they redesign things. ;-)

Rafael


> ---
>  kernel/power/power.h    |    7 --
>  kernel/power/snapshot.c |  196 +++++++++++++++++++++++++++++++++++++++++++++--
>  kernel/power/swap.c     |  182 -------------------------------------------
>  3 files changed, 189 insertions(+), 196 deletions(-)
> 
> diff --git a/kernel/power/power.h b/kernel/power/power.h
> index cf1450f..29c450a 100644
> --- a/kernel/power/power.h
> +++ b/kernel/power/power.h
> @@ -128,14 +128,7 @@ struct sws_module_ops {
>  	int (*write_page)(void *addr, struct bio **bio_chain);
>  };
>  
> -extern unsigned int snapshot_additional_pages(struct zone *zone);
>  extern unsigned long snapshot_get_image_size(void);
> -extern int snapshot_read_init(struct snapshot_handle *handle);
> -extern int snapshot_write_init(struct snapshot_handle *handle);
> -extern int snapshot_read_next(struct snapshot_handle *handle);
> -extern int snapshot_write_next(struct snapshot_handle *handle);
> -extern void snapshot_write_finalize(struct snapshot_handle *handle);
> -extern int snapshot_image_loaded(struct snapshot_handle *handle);
>  
>  /* If unset, the snapshot device cannot be open. */
>  extern atomic_t snapshot_device_available;
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index d432e87..a8a28da 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -789,7 +789,7 @@ void free_basic_memory_bitmaps(void)
>   *	zone (usually the returned value is greater than the exact number)
>   */
>  
> -unsigned int snapshot_additional_pages(struct zone *zone)
> +static unsigned int snapshot_additional_pages(struct zone *zone)
>  {
>  	unsigned int res;
>  
> @@ -1605,7 +1605,7 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
>   *
>   *	@handle: snapshot handle to init
>   */
> -int snapshot_write_init(struct snapshot_handle *handle)
> +static int snapshot_write_init(struct snapshot_handle *handle)
>  {
>  	int ret;
>  
> @@ -1646,7 +1646,7 @@ finish:
>   *	structure pointed to by @handle is not updated and should not be used
>   *	any more.
>   */
> -int snapshot_read_next(struct snapshot_handle *handle)
> +static int snapshot_read_next(struct snapshot_handle *handle)
>  {
>  	if (handle->cur < nr_meta_pages) {
>  		memset(buffer, 0, PAGE_SIZE);
> @@ -2134,7 +2134,7 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
>   *
>   *	@handle: snapshot handle to init
>   */
> -int snapshot_read_init(struct snapshot_handle *handle)
> +static int snapshot_read_init(struct snapshot_handle *handle)
>  {
>  	int ret;
>  
> @@ -2183,7 +2183,7 @@ finish:
>   *	structure pointed to by @handle is not updated and should not be used
>   *	any more.
>   */
> -int snapshot_write_next(struct snapshot_handle *handle)
> +static int snapshot_write_next(struct snapshot_handle *handle)
>  {
>  	static struct chain_allocator ca;
>  	int error = 0;
> @@ -2235,7 +2235,7 @@ int snapshot_write_next(struct snapshot_handle *handle)
>   *	used any more.
>   */
>  
> -void snapshot_write_finalize(struct snapshot_handle *handle)
> +static void snapshot_write_finalize(struct snapshot_handle *handle)
>  {
>  	copy_last_highmem_page();
>  	/* Free only if we have loaded the image entirely */
> @@ -2245,12 +2245,194 @@ void snapshot_write_finalize(struct snapshot_handle *handle)
>  	}
>  }
>  
> -int snapshot_image_loaded(struct snapshot_handle *handle)
> +static int snapshot_image_loaded(struct snapshot_handle *handle)
>  {
>  	return !(!nr_copy_pages || !last_highmem_page_copied() ||
>  			handle->cur < nr_meta_pages + nr_copy_pages);
>  }
>  
> +/**
> + *	save_image - save the suspend image data
> + */
> +
> +static int save_image(struct snapshot_handle *snapshot,
> +                      unsigned int nr_to_write)
> +{
> +	unsigned int m;
> +	int ret;
> +	int nr_pages;
> +	int err2;
> +	struct bio *bio;
> +	struct timeval start;
> +	struct timeval stop;
> +
> +	printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
> +		nr_to_write);
> +	m = nr_to_write / 100;
> +	if (!m)
> +		m = 1;
> +	nr_pages = 0;
> +	bio = NULL;
> +	do_gettimeofday(&start);
> +	while (1) {
> +		ret = snapshot_read_next(snapshot);
> +		if (ret <= 0)
> +			break;
> +		ret = sws_io_ops->write_page(data_of(*snapshot), &bio);
> +		if (ret)
> +			break;
> +		if (!(nr_pages % m))
> +			printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
> +		nr_pages++;
> +	}
> +	err2 = sws_wait_on_bio_chain(&bio);
> +	do_gettimeofday(&stop);
> +	if (!ret)
> +		ret = err2;
> +	if (!ret)
> +		printk(KERN_CONT "\b\b\b\bdone\n");
> +	else
> +		printk(KERN_CONT "\n");
> +	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
> +	return ret;
> +}
> +
> +/**
> + *	enough_space - Make sure we have enough space to save the image.
> + *
> + *	Returns TRUE or FALSE after checking the total amount of
> + *	space avaiable from the resume block.
> + */
> +
> +static int enough_space(unsigned int nr_pages)
> +{
> +	unsigned int free_pages = sws_io_ops->storage_available();
> +
> +	pr_debug("PM: Free storage pages: %u\n", free_pages);
> +	return free_pages > nr_pages + PAGES_FOR_IO;
> +}
> +
> +/**
> + *	swsusp_write - Write entire image and metadata.
> + *	@flags: flags to pass to the "boot" kernel in the image header
> + *
> + *	It is important _NOT_ to umount filesystems at this point. We want
> + *	them synced (in case something goes wrong) but we DO not want to mark
> + *	filesystem clean: it is not. (And it does not matter, if we resume
> + *	correctly, we'll mark system clean, anyway.)
> + */
> +
> +int swsusp_write(unsigned int flags)
> +{
> +	struct snapshot_handle snapshot;
> +	unsigned long pages;
> +	int error;
> +
> +	pages = snapshot_get_image_size();
> +	error = sws_io_ops->get_writer();
> +	if (error) {
> +		printk(KERN_ERR "PM: Cannot get swap writer\n");
> +		return error;
> +	}
> +	if (!enough_space(pages)) {
> +		printk(KERN_ERR "PM: Not enough free space for image\n");
> +		error = -ENOSPC;
> +		goto out_finish;
> +	}
> +	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> +	error = snapshot_write_init(&snapshot);
> +	if (error) {
> +		printk(KERN_ERR "PM: Cannot init writer\n");
> +		goto out_finish;
> +	}
> +	error = save_image(&snapshot, pages - 1);
> +out_finish:
> +	error = sws_io_ops->put_writer(flags, error);
> +	return error;
> +}
> +
> +/**
> + *	load_image - load the image
> + *	@handle and the snapshot handle @snapshot
> + *	(assume there are @nr_pages pages to load)
> + */
> +
> +static int load_image(struct snapshot_handle *snapshot, unsigned int nr_to_read)
> +{
> +	unsigned int m;
> +	int error = 0;
> +	struct timeval start;
> +	struct timeval stop;
> +	struct bio *bio;
> +	int err2;
> +	unsigned nr_pages;
> +
> +	printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
> +		nr_to_read);
> +	m = nr_to_read / 100;
> +	if (!m)
> +		m = 1;
> +	nr_pages = 0;
> +	bio = NULL;
> +	do_gettimeofday(&start);
> +	for ( ; ; ) {
> +		error = sws_io_ops->read_page(data_of(*snapshot), &bio);
> +		if (error)
> +			break;
> +		if (snapshot->sync_read)
> +			error = sws_wait_on_bio_chain(&bio);
> +		if (error)
> +			break;
> +		error = snapshot_write_next(snapshot);
> +		if (error >= 0)
> +			nr_pages++;
> +		if (error <= 0)
> +			break;
> +		if (!(nr_pages % m))
> +			printk("\b\b\b\b%3d%%", nr_pages / m);
> +	}
> +	err2 = sws_wait_on_bio_chain(&bio);
> +	do_gettimeofday(&stop);
> +	if (!error)
> +		error = err2;
> +	if (!error) {
> +		printk("\b\b\b\bdone\n");
> +		snapshot_write_finalize(snapshot);
> +		if (!snapshot_image_loaded(snapshot))
> +			error = -ENODATA;
> +	} else
> +		printk("\n");
> +	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
> +	return error;
> +}
> +
> +/**
> + *	swsusp_read - read the hibernation image.
> + *	@flags_p: flags passed by the "frozen" kernel in the image header should
> + *		  be written into this memeory location
> + */
> +
> +int swsusp_read(unsigned int *flags_p)
> +{
> +	int error;
> +	struct snapshot_handle snapshot;
> +
> +	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> +	error = sws_io_ops->get_reader(flags_p);
> +	if (error)
> +		goto end;
> +	error = snapshot_read_init(&snapshot);
> +	if (!error)
> +		error = load_image(&snapshot, snapshot_get_image_size() - 1);
> +	sws_io_ops->put_reader();
> +end:
> +	if (!error)
> +		pr_debug("PM: Image successfully loaded\n");
> +	else
> +		pr_debug("PM: Error %d resuming\n", error);
> +	return error;
> +}
> +
>  #ifdef CONFIG_HIGHMEM
>  /* Assumes that @buf is ready and points to a "safe" page */
>  static inline void
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index 4472cf3..ddd7238 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -360,106 +360,6 @@ static int put_swap_writer(unsigned int flags, int error)
>  	return error;
>  }
>  
> -/**
> - *	save_image - save the suspend image data
> - */
> -
> -static int save_image(struct snapshot_handle *snapshot,
> -                      unsigned int nr_to_write)
> -{
> -	unsigned int m;
> -	int ret;
> -	int nr_pages;
> -	int err2;
> -	struct bio *bio;
> -	struct timeval start;
> -	struct timeval stop;
> -
> -	printk(KERN_INFO "PM: Saving image data pages (%u pages) ...     ",
> -		nr_to_write);
> -	m = nr_to_write / 100;
> -	if (!m)
> -		m = 1;
> -	nr_pages = 0;
> -	bio = NULL;
> -	do_gettimeofday(&start);
> -	while (1) {
> -		ret = snapshot_read_next(snapshot);
> -		if (ret <= 0)
> -			break;
> -		ret = sws_io_ops->write_page(data_of(*snapshot), &bio);
> -		if (ret)
> -			break;
> -		if (!(nr_pages % m))
> -			printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
> -		nr_pages++;
> -	}
> -	err2 = sws_wait_on_bio_chain(&bio);
> -	do_gettimeofday(&stop);
> -	if (!ret)
> -		ret = err2;
> -	if (!ret)
> -		printk(KERN_CONT "\b\b\b\bdone\n");
> -	else
> -		printk(KERN_CONT "\n");
> -	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
> -	return ret;
> -}
> -
> -/**
> - *	enough_space - Make sure we have enough space to save the image.
> - *
> - *	Returns TRUE or FALSE after checking the total amount of
> - *	space avaiable from the resume block.
> - */
> -
> -static int enough_space(unsigned int nr_pages)
> -{
> -	unsigned int free_pages = sws_io_ops->storage_available();
> -
> -	pr_debug("PM: Free storage pages: %u\n", free_pages);
> -	return free_pages > nr_pages + PAGES_FOR_IO;
> -}
> -
> -/**
> - *	swsusp_write - Write entire image and metadata.
> - *	@flags: flags to pass to the "boot" kernel in the image header
> - *
> - *	It is important _NOT_ to umount filesystems at this point. We want
> - *	them synced (in case something goes wrong) but we DO not want to mark
> - *	filesystem clean: it is not. (And it does not matter, if we resume
> - *	correctly, we'll mark system clean, anyway.)
> - */
> -
> -int swsusp_write(unsigned int flags)
> -{
> -	struct snapshot_handle snapshot;
> -	unsigned long pages;
> -	int error;
> -
> -	pages = snapshot_get_image_size();
> -	error = sws_io_ops->get_writer();
> -	if (error) {
> -		printk(KERN_ERR "PM: Cannot get swap writer\n");
> -		return error;
> -	}
> -	if (!enough_space(pages)) {
> -		printk(KERN_ERR "PM: Not enough free space for image\n");
> -		error = -ENOSPC;
> -		goto out_finish;
> -	}
> -	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> -	error = snapshot_write_init(&snapshot);
> -	if (error) {
> -		printk(KERN_ERR "PM: Cannot init writer\n");
> -		goto out_finish;
> -	}
> -	error = save_image(&snapshot, pages - 1);
> -out_finish:
> -	error = sws_io_ops->put_writer(flags, error);
> -	return error;
> -}
> -
>  static unsigned long swap_storage_available(void)
>  {
>  	return count_swap_pages(root_swap, 1);
> @@ -546,88 +446,6 @@ struct sws_module_ops swap_ops = {
>  };
>  
>  /**
> - *	load_image - load the image
> - *	@handle and the snapshot handle @snapshot
> - *	(assume there are @nr_pages pages to load)
> - */
> -
> -static int load_image(struct snapshot_handle *snapshot, unsigned int nr_to_read)
> -{
> -	unsigned int m;
> -	int error = 0;
> -	struct timeval start;
> -	struct timeval stop;
> -	struct bio *bio;
> -	int err2;
> -	unsigned nr_pages;
> -
> -	printk(KERN_INFO "PM: Loading image data pages (%u pages) ...     ",
> -		nr_to_read);
> -	m = nr_to_read / 100;
> -	if (!m)
> -		m = 1;
> -	nr_pages = 0;
> -	bio = NULL;
> -	do_gettimeofday(&start);
> -	for ( ; ; ) {
> -		error = sws_io_ops->read_page(data_of(*snapshot), &bio);
> -		if (error)
> -			break;
> -		if (snapshot->sync_read)
> -			error = sws_wait_on_bio_chain(&bio);
> -		if (error)
> -			break;
> -		error = snapshot_write_next(snapshot);
> -		if (error >= 0)
> -			nr_pages++;
> -		if (error <= 0)
> -			break;
> -		if (!(nr_pages % m))
> -			printk("\b\b\b\b%3d%%", nr_pages / m);
> -	}
> -	err2 = sws_wait_on_bio_chain(&bio);
> -	do_gettimeofday(&stop);
> -	if (!error)
> -		error = err2;
> -	if (!error) {
> -		printk("\b\b\b\bdone\n");
> -		snapshot_write_finalize(snapshot);
> -		if (!snapshot_image_loaded(snapshot))
> -			error = -ENODATA;
> -	} else
> -		printk("\n");
> -	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
> -	return error;
> -}
> -
> -/**
> - *	swsusp_read - read the hibernation image.
> - *	@flags_p: flags passed by the "frozen" kernel in the image header should
> - *		  be written into this memeory location
> - */
> -
> -int swsusp_read(unsigned int *flags_p)
> -{
> -	int error;
> -	struct snapshot_handle snapshot;
> -
> -	memset(&snapshot, 0, sizeof(struct snapshot_handle));
> -	error = sws_io_ops->get_reader(flags_p);
> -	if (error)
> -		goto end;
> -	error = snapshot_read_init(&snapshot);
> -	if (!error)
> -		error = load_image(&snapshot, snapshot_get_image_size() - 1);
> -	sws_io_ops->put_reader();
> -end:
> -	if (!error)
> -		pr_debug("PM: Image successfully loaded\n");
> -	else
> -		pr_debug("PM: Error %d resuming\n", error);
> -	return error;
> -}
> -
> -/**
>   *      swsusp_check - Check for swsusp signature in the resume device
>   */
>  
> 

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