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!

1 files changed, 160 insertions, 0 deletions

diff --git a/mm/page_io.c b/mm/page_io.c
new file mode 100644
index 000000000000..667c76df1ec2
--- /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