[PATCH] swsusp: read speedup
Implement async reads for swsusp resuming. Crufty old PIII testbox: 15.7 MB/s -> 20.3 MB/s Sony Vaio: 14.6 MB/s -> 33.3 MB/s I didn't implement the post-resume bio_set_pages_dirty(). I don't really understand why resume needs to run set_page_dirty() against these pages. It might be a worry that this code modifies PG_Uptodate, PG_Error and PG_Locked against the image pages. Can this possibly affect the resumed-into kernel? Hopefully not, if we're atomically restoring its mem_map? Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Jens Axboe <axboe@suse.de> Cc: Laurent Riffard <laurent.riffard@free.fr> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton
Linus Torvalds
Родитель
8c002494b5
Коммит
546e0d2719
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@ -220,6 +220,7 @@ extern int swap_readpage(struct file *, struct page *);
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extern int swap_writepage(struct page *page, struct writeback_control *wbc);
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extern int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page,
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struct bio **bio_chain);
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extern int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err);
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/* linux/mm/swap_state.c */
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extern struct address_space swapper_space;
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@ -58,6 +58,7 @@ struct snapshot_handle {
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struct pbe *pbe, *last_pbe;
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void *buffer;
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unsigned int buf_offset;
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int sync_read;
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};
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#define data_of(handle) ((handle).buffer + (handle).buf_offset)
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@ -314,7 +314,7 @@ static unsigned int unsafe_pages;
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* and we count them using unsafe_pages
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*/
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static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
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static void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
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{
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void *res;
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@ -828,13 +828,16 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
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}
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if (!handle->offset)
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handle->buffer = buffer;
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handle->sync_read = 1;
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if (handle->prev < handle->page) {
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if (!handle->prev) {
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error = load_header(handle, (struct swsusp_info *)buffer);
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error = load_header(handle,
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(struct swsusp_info *)buffer);
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if (error)
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return error;
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} else if (handle->prev <= nr_meta_pages) {
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handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
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handle->pbe = unpack_orig_addresses(buffer,
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handle->pbe);
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if (!handle->pbe) {
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error = prepare_image(handle);
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if (error)
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@ -842,10 +845,12 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
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handle->pbe = pagedir_nosave;
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handle->last_pbe = NULL;
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handle->buffer = get_buffer(handle);
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handle->sync_read = 0;
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}
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} else {
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handle->pbe = handle->pbe->next;
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handle->buffer = get_buffer(handle);
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handle->sync_read = 0;
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}
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handle->prev = handle->page;
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}
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@ -22,6 +22,7 @@
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#include <linux/device.h>
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#include <linux/buffer_head.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <linux/pm.h>
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@ -214,6 +215,8 @@ static int wait_on_bio_chain(struct bio **bio_chain)
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return 0;
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bio = *bio_chain;
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if (bio == NULL)
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return 0;
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while (bio) {
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struct page *page;
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@ -349,7 +352,8 @@ int swsusp_write(void)
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int error;
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if ((error = swsusp_swap_check())) {
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printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n");
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printk(KERN_ERR "swsusp: Cannot find swap device, try "
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"swapon -a.\n");
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return error;
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}
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memset(&snapshot, 0, sizeof(struct snapshot_handle));
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@ -381,27 +385,6 @@ int swsusp_write(void)
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return error;
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}
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/*
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* Using bio to read from swap.
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* This code requires a bit more work than just using buffer heads
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* but, it is the recommended way for 2.5/2.6.
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* The following are to signal the beginning and end of I/O. Bios
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* finish asynchronously, while we want them to happen synchronously.
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* A simple atomic_t, and a wait loop take care of this problem.
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*/
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static atomic_t io_done = ATOMIC_INIT(0);
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static int end_io(struct bio *bio, unsigned int num, int err)
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{
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if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
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printk(KERN_ERR "I/O error reading swsusp image.\n");
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return -EIO;
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}
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atomic_set(&io_done, 0);
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return 0;
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}
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static struct block_device *resume_bdev;
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/**
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@ -409,15 +392,15 @@ static struct block_device *resume_bdev;
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* @rw: READ or WRITE.
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* @off physical offset of page.
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* @page: page we're reading or writing.
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* @bio_chain: list of pending biod (for async reading)
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*
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* Straight from the textbook - allocate and initialize the bio.
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* If we're writing, make sure the page is marked as dirty.
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* Then submit it and wait.
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* If we're reading, make sure the page is marked as dirty.
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* Then submit it and, if @bio_chain == NULL, wait.
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*/
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static int submit(int rw, pgoff_t page_off, void *page)
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static int submit(int rw, pgoff_t page_off, struct page *page,
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struct bio **bio_chain)
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{
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int error = 0;
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struct bio *bio;
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bio = bio_alloc(GFP_ATOMIC, 1);
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@ -425,33 +408,40 @@ static int submit(int rw, pgoff_t page_off, void *page)
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return -ENOMEM;
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bio->bi_sector = page_off * (PAGE_SIZE >> 9);
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bio->bi_bdev = resume_bdev;
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bio->bi_end_io = end_io;
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bio->bi_end_io = end_swap_bio_read;
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if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
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printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
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error = -EFAULT;
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goto Done;
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if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
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printk("swsusp: ERROR: adding page to bio at %ld\n", page_off);
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bio_put(bio);
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return -EFAULT;
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}
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atomic_set(&io_done, 1);
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submit_bio(rw | (1 << BIO_RW_SYNC), bio);
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while (atomic_read(&io_done))
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yield();
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if (rw == READ)
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bio_set_pages_dirty(bio);
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Done:
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bio_put(bio);
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return error;
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lock_page(page);
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bio_get(bio);
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if (bio_chain == NULL) {
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submit_bio(rw | (1 << BIO_RW_SYNC), bio);
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wait_on_page_locked(page);
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if (rw == READ)
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bio_set_pages_dirty(bio);
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bio_put(bio);
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} else {
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get_page(page);
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bio->bi_private = *bio_chain;
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*bio_chain = bio;
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submit_bio(rw | (1 << BIO_RW_SYNC), bio);
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}
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return 0;
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}
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static int bio_read_page(pgoff_t page_off, void *page)
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static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
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{
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return submit(READ, page_off, page);
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return submit(READ, page_off, virt_to_page(addr), bio_chain);
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}
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static int bio_write_page(pgoff_t page_off, void *page)
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static int bio_write_page(pgoff_t page_off, void *addr)
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{
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return submit(WRITE, page_off, page);
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return submit(WRITE, page_off, virt_to_page(addr), NULL);
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}
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/**
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@ -476,7 +466,7 @@ static int get_swap_reader(struct swap_map_handle *handle,
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handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
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if (!handle->cur)
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return -ENOMEM;
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error = bio_read_page(swp_offset(start), handle->cur);
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error = bio_read_page(swp_offset(start), handle->cur, NULL);
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if (error) {
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release_swap_reader(handle);
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return error;
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@ -485,7 +475,8 @@ static int get_swap_reader(struct swap_map_handle *handle,
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return 0;
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}
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static int swap_read_page(struct swap_map_handle *handle, void *buf)
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static int swap_read_page(struct swap_map_handle *handle, void *buf,
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struct bio **bio_chain)
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{
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unsigned long offset;
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int error;
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@ -495,16 +486,17 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf)
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offset = handle->cur->entries[handle->k];
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if (!offset)
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return -EFAULT;
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error = bio_read_page(offset, buf);
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error = bio_read_page(offset, buf, bio_chain);
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if (error)
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return error;
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if (++handle->k >= MAP_PAGE_ENTRIES) {
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error = wait_on_bio_chain(bio_chain);
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handle->k = 0;
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offset = handle->cur->next_swap;
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if (!offset)
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release_swap_reader(handle);
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else
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error = bio_read_page(offset, handle->cur);
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else if (!error)
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error = bio_read_page(offset, handle->cur, NULL);
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}
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return error;
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}
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@ -517,38 +509,48 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf)
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static int load_image(struct swap_map_handle *handle,
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struct snapshot_handle *snapshot,
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unsigned int nr_pages)
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unsigned int nr_to_read)
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{
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unsigned int m;
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int ret;
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int error = 0;
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struct timeval start;
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struct timeval stop;
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struct bio *bio;
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int err2;
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unsigned nr_pages;
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printk("Loading image data pages (%u pages) ... ", nr_pages);
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m = nr_pages / 100;
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printk("Loading image data pages (%u pages) ... ", nr_to_read);
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m = nr_to_read / 100;
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if (!m)
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m = 1;
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nr_pages = 0;
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bio = NULL;
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do_gettimeofday(&start);
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do {
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ret = snapshot_write_next(snapshot, PAGE_SIZE);
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if (ret > 0) {
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error = swap_read_page(handle, data_of(*snapshot));
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if (error)
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break;
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if (!(nr_pages % m))
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printk("\b\b\b\b%3d%%", nr_pages / m);
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nr_pages++;
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}
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} while (ret > 0);
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for ( ; ; ) {
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error = snapshot_write_next(snapshot, PAGE_SIZE);
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if (error <= 0)
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break;
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error = swap_read_page(handle, data_of(*snapshot), &bio);
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if (error)
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break;
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if (snapshot->sync_read)
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error = wait_on_bio_chain(&bio);
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if (error)
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break;
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if (!(nr_pages % m))
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printk("\b\b\b\b%3d%%", nr_pages / m);
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nr_pages++;
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}
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err2 = wait_on_bio_chain(&bio);
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do_gettimeofday(&stop);
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if (!error)
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error = err2;
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if (!error) {
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printk("\b\b\b\bdone\n");
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if (!snapshot_image_loaded(snapshot))
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error = -ENODATA;
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}
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show_speed(&start, &stop, nr_pages, "Read");
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show_speed(&start, &stop, nr_to_read, "Read");
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return error;
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}
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@ -571,7 +573,7 @@ int swsusp_read(void)
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header = (struct swsusp_info *)data_of(snapshot);
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error = get_swap_reader(&handle, swsusp_header.image);
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if (!error)
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error = swap_read_page(&handle, header);
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error = swap_read_page(&handle, header, NULL);
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if (!error)
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error = load_image(&handle, &snapshot, header->pages - 1);
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release_swap_reader(&handle);
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@ -597,7 +599,7 @@ int swsusp_check(void)
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if (!IS_ERR(resume_bdev)) {
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set_blocksize(resume_bdev, PAGE_SIZE);
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memset(&swsusp_header, 0, sizeof(swsusp_header));
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if ((error = bio_read_page(0, &swsusp_header)))
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if ((error = bio_read_page(0, &swsusp_header, NULL)))
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return error;
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if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
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memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);
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@ -74,7 +74,7 @@ static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
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return 0;
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}
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static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
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int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
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{
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const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
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struct page *page = bio->bi_io_vec[0].bv_page;
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