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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 22:20:36 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 22:20:36 (GMT)
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /mm/page_io.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'mm/page_io.c')
-rw-r--r--mm/page_io.c160
1 files changed, 160 insertions, 0 deletions
diff --git a/mm/page_io.c b/mm/page_io.c
new file mode 100644
index 0000000..667c76d
--- /dev/null
+++ b/mm/page_io.c
@@ -0,0 +1,160 @@
+/*
+ * linux/mm/page_io.c
+ *
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ *
+ * Swap reorganised 29.12.95,
+ * Asynchronous swapping added 30.12.95. Stephen Tweedie
+ * Removed race in async swapping. 14.4.1996. Bruno Haible
+ * Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
+ * Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
+ */
+
+#include <linux/mm.h>
+#include <linux/kernel_stat.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/bio.h>
+#include <linux/swapops.h>
+#include <linux/writeback.h>
+#include <asm/pgtable.h>
+
+static struct bio *get_swap_bio(unsigned int __nocast gfp_flags, pgoff_t index,
+ struct page *page, bio_end_io_t end_io)
+{
+ struct bio *bio;
+
+ bio = bio_alloc(gfp_flags, 1);
+ if (bio) {
+ struct swap_info_struct *sis;
+ swp_entry_t entry = { .val = index, };
+
+ sis = get_swap_info_struct(swp_type(entry));
+ bio->bi_sector = map_swap_page(sis, swp_offset(entry)) *
+ (PAGE_SIZE >> 9);
+ bio->bi_bdev = sis->bdev;
+ bio->bi_io_vec[0].bv_page = page;
+ bio->bi_io_vec[0].bv_len = PAGE_SIZE;
+ bio->bi_io_vec[0].bv_offset = 0;
+ bio->bi_vcnt = 1;
+ bio->bi_idx = 0;
+ bio->bi_size = PAGE_SIZE;
+ bio->bi_end_io = end_io;
+ }
+ return bio;
+}
+
+static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
+{
+ const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct page *page = bio->bi_io_vec[0].bv_page;
+
+ if (bio->bi_size)
+ return 1;
+
+ if (!uptodate)
+ SetPageError(page);
+ end_page_writeback(page);
+ bio_put(bio);
+ return 0;
+}
+
+static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
+{
+ const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ struct page *page = bio->bi_io_vec[0].bv_page;
+
+ if (bio->bi_size)
+ return 1;
+
+ if (!uptodate) {
+ SetPageError(page);
+ ClearPageUptodate(page);
+ } else {
+ SetPageUptodate(page);
+ }
+ unlock_page(page);
+ bio_put(bio);
+ return 0;
+}
+
+/*
+ * We may have stale swap cache pages in memory: notice
+ * them here and get rid of the unnecessary final write.
+ */
+int swap_writepage(struct page *page, struct writeback_control *wbc)
+{
+ struct bio *bio;
+ int ret = 0, rw = WRITE;
+
+ if (remove_exclusive_swap_page(page)) {
+ unlock_page(page);
+ goto out;
+ }
+ bio = get_swap_bio(GFP_NOIO, page->private, page, end_swap_bio_write);
+ if (bio == NULL) {
+ set_page_dirty(page);
+ unlock_page(page);
+ ret = -ENOMEM;
+ goto out;
+ }
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ rw |= (1 << BIO_RW_SYNC);
+ inc_page_state(pswpout);
+ set_page_writeback(page);
+ unlock_page(page);
+ submit_bio(rw, bio);
+out:
+ return ret;
+}
+
+int swap_readpage(struct file *file, struct page *page)
+{
+ struct bio *bio;
+ int ret = 0;
+
+ BUG_ON(!PageLocked(page));
+ ClearPageUptodate(page);
+ bio = get_swap_bio(GFP_KERNEL, page->private, page, end_swap_bio_read);
+ if (bio == NULL) {
+ unlock_page(page);
+ ret = -ENOMEM;
+ goto out;
+ }
+ inc_page_state(pswpin);
+ submit_bio(READ, bio);
+out:
+ return ret;
+}
+
+#if defined(CONFIG_SOFTWARE_SUSPEND) || defined(CONFIG_PM_DISK)
+/*
+ * A scruffy utility function to read or write an arbitrary swap page
+ * and wait on the I/O. The caller must have a ref on the page.
+ *
+ * We use end_swap_bio_read() even for writes, because it happens to do what
+ * we want.
+ */
+int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page)
+{
+ struct bio *bio;
+ int ret = 0;
+
+ lock_page(page);
+
+ bio = get_swap_bio(GFP_KERNEL, entry.val, page, end_swap_bio_read);
+ if (bio == NULL) {
+ unlock_page(page);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ submit_bio(rw | (1 << BIO_RW_SYNC), bio);
+ wait_on_page_locked(page);
+
+ if (!PageUptodate(page) || PageError(page))
+ ret = -EIO;
+out:
+ return ret;
+}
+#endif

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