On Saturday, September 25, 2010, Nigel Cunningham wrote:
> Switch from allocating swap as the image is written to allocating
> storage prior to writing the image.
Hmm, I think I know what the patch does, but I don't really understand the
changelog. Care to explain/fix?
Thanks,
Rafael
> Signed-off-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
> ---
> kernel/power/swap.c | 62 ++++++++++++++++++++++++++++++--------------------
> 1 files changed, 37 insertions(+), 25 deletions(-)
>
> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
> index cebf91c..bebd2cf 100644
> --- a/kernel/power/swap.c
> +++ b/kernel/power/swap.c
> @@ -202,6 +202,33 @@ int alloc_swapdev_blocks(int needed)
> }
>
> /**
> + * allocate_swap - Allocate enough swap to save the image.
> + *
> + * Calculates the number of swap pages actually needed and seeks
> + * to allocate that many from the resume partition. Returns TRUE
> + * or FALSE to indicate whether we got enough storage.
> + */
> +
> +static int allocate_swap(unsigned int nr_pages)
> +{
> + unsigned int free_swap = count_swap_pages(root_swap, 1);
> +
> + nr_pages += DIV_ROUND_UP(nr_pages, MAP_PAGE_ENTRIES);
> +
> + pr_debug("PM: Free swap pages: %u\n", free_swap);
> + if (free_swap < nr_pages)
> + return 0;
> +
> + if (alloc_swapdev_blocks(nr_pages) < nr_pages) {
> + free_all_swap_pages(root_swap);
> + return 0;
> + }
> +
> + reset_storage_pos();
> + return 1;
> +}
> +
> +/**
> * free_all_swap_pages - free swap pages allocated for saving image data.
> * It also frees the extents used to register which swap entries had been
> * allocated.
> @@ -324,7 +351,7 @@ static void release_swap_writer(struct swap_map_handle *handle)
> handle->cur = NULL;
> }
>
> -static int get_swap_writer(struct swap_map_handle *handle)
> +static int get_swap_writer(struct swap_map_handle *handle, unsigned long pages)
> {
> int ret;
>
> @@ -340,7 +367,12 @@ static int get_swap_writer(struct swap_map_handle *handle)
> ret = -ENOMEM;
> goto err_close;
> }
> - handle->cur_swap = alloc_swapdev_block(root_swap);
> + if (!allocate_swap(pages)) {
> + printk(KERN_ERR "PM: Not enough free swap\n");
> + ret = -ENOSPC;
> + goto err_close;
> + }
> + handle->cur_swap = next_swapdev_block();
> if (!handle->cur_swap) {
> ret = -ENOSPC;
> goto err_rel;
> @@ -363,7 +395,7 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
>
> if (!handle->cur)
> return -EINVAL;
> - offset = alloc_swapdev_block(root_swap);
> + offset = next_swapdev_block();
> error = write_page(buf, offset, bio_chain);
> if (error)
> return error;
> @@ -372,7 +404,7 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
> error = hib_wait_on_bio_chain(bio_chain);
> if (error)
> goto out;
> - offset = alloc_swapdev_block(root_swap);
> + offset = next_swapdev_block();
> if (!offset)
> return -ENOSPC;
> handle->cur->next_swap = offset;
> @@ -463,21 +495,6 @@ static int save_image(struct swap_map_handle *handle,
> }
>
> /**
> - * enough_swap - Make sure we have enough swap to save the image.
> - *
> - * Returns TRUE or FALSE after checking the total amount of swap
> - * space avaiable from the resume partition.
> - */
> -
> -static int enough_swap(unsigned int nr_pages)
> -{
> - unsigned int free_swap = count_swap_pages(root_swap, 1);
> -
> - pr_debug("PM: Free swap pages: %u\n", free_swap);
> - return free_swap > nr_pages + PAGES_FOR_IO;
> -}
> -
> -/**
> * swsusp_write - Write entire image and metadata.
> * @flags: flags to pass to the "boot" kernel in the image header
> *
> @@ -496,16 +513,11 @@ int swsusp_write(unsigned int flags)
> int error;
>
> pages = snapshot_get_image_size();
> - error = get_swap_writer(&handle);
> + error = get_swap_writer(&handle, pages);
> if (error) {
> printk(KERN_ERR "PM: Cannot get swap writer\n");
> return error;
> }
> - if (!enough_swap(pages)) {
> - printk(KERN_ERR "PM: Not enough free swap\n");
> - error = -ENOSPC;
> - goto out_finish;
> - }
> memset(&snapshot, 0, sizeof(struct snapshot_handle));
> error = snapshot_read_next(&snapshot);
> if (error < PAGE_SIZE) {
>
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