PM / Hibernate: Separate block_io

Move block I/O operations to a separate file. It is because it will
be used later not only by the swap writer.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 103 insertions, 0 deletions

diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
new file mode 100644
index 00000000000..2a2f8aed8e5
--- /dev/null
+++ b/kernel/power/block_io.c
@@ -0,0 +1,103 @@
+/*
+ * This file provides functions for block I/O operations on swap/file.
+ *
+ * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/bio.h>
+#include <linux/kernel.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+
+#include "power.h"
+
+/**
+ *	submit - submit BIO request.
+ *	@rw:	READ or WRITE.
+ *	@off	physical offset of page.
+ *	@page:	page we're reading or writing.
+ *	@bio_chain: list of pending biod (for async reading)
+ *
+ *	Straight from the textbook - allocate and initialize the bio.
+ *	If we're reading, make sure the page is marked as dirty.
+ *	Then submit it and, if @bio_chain == NULL, wait.
+ */
+static int submit(int rw, struct block_device *bdev, sector_t sector,
+		struct page *page, struct bio **bio_chain)
+{
+	const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
+	struct bio *bio;
+
+	bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
+	bio->bi_sector = sector;
+	bio->bi_bdev = bdev;
+	bio->bi_end_io = end_swap_bio_read;
+
+	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
+		printk(KERN_ERR "PM: Adding page to bio failed at %ld\n",
+			sector);
+		bio_put(bio);
+		return -EFAULT;
+	}
+
+	lock_page(page);
+	bio_get(bio);
+
+	if (bio_chain == NULL) {
+		submit_bio(bio_rw, bio);
+		wait_on_page_locked(page);
+		if (rw == READ)
+			bio_set_pages_dirty(bio);
+		bio_put(bio);
+	} else {
+		if (rw == READ)
+			get_page(page);	/* These pages are freed later */
+		bio->bi_private = *bio_chain;
+		*bio_chain = bio;
+		submit_bio(bio_rw, bio);
+	}
+	return 0;
+}
+
+int hib_bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
+{
+	return submit(READ, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
+			virt_to_page(addr), bio_chain);
+}
+
+int hib_bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
+{
+	return submit(WRITE, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
+			virt_to_page(addr), bio_chain);
+}
+
+int hib_wait_on_bio_chain(struct bio **bio_chain)
+{
+	struct bio *bio;
+	struct bio *next_bio;
+	int ret = 0;
+
+	if (bio_chain == NULL)
+		return 0;
+
+	bio = *bio_chain;
+	if (bio == NULL)
+		return 0;
+	while (bio) {
+		struct page *page;
+
+		next_bio = bio->bi_private;
+		page = bio->bi_io_vec[0].bv_page;
+		wait_on_page_locked(page);
+		if (!PageUptodate(page) || PageError(page))
+			ret = -EIO;
+		put_page(page);
+		bio_put(bio);
+		bio = next_bio;
+	}
+	*bio_chain = NULL;
+	return ret;
+}