add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/kernel/power/swap.c
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@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * linux/kernel/power/swap.c
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  *
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@@ -7,9 +8,6 @@
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  * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
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  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
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  * Copyright (C) 2010-2012 Bojan Smojver <bojan@rexursive.com>
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- *
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- * This file is released under the GPLv2.
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- *
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  */
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 #define pr_fmt(fmt) "PM: " fmt
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@@ -228,6 +226,7 @@
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 	atomic_t		count;
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 	wait_queue_head_t	wait;
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 	blk_status_t		error;
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+	struct blk_plug		plug;
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 };
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 static void hib_init_batch(struct hib_bio_batch *hb)
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@@ -235,6 +234,12 @@
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 	atomic_set(&hb->count, 0);
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 	init_waitqueue_head(&hb->wait);
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 	hb->error = BLK_STS_OK;
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+	blk_start_plug(&hb->plug);
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+}
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+
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+static void hib_finish_batch(struct hib_bio_batch *hb)
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+{
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+	blk_finish_plug(&hb->plug);
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 }
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 static void hib_end_io(struct bio *bio)
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@@ -296,6 +301,10 @@
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 static int hib_wait_io(struct hib_bio_batch *hb)
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 {
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+	/*
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+	 * We are relying on the behavior of blk_plug that a thread with
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+	 * a plug will flush the plug list before sleeping.
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+	 */
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 	wait_event(hb->wait, atomic_read(&hb->count) == 0);
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 	return blk_status_to_errno(hb->error);
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 }
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@@ -337,26 +346,23 @@
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 {
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 	int res;
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-	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
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-			&hib_resume_bdev);
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+	if (swsusp_resume_device)
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+		res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
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+	else
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+		res = find_first_swap(&swsusp_resume_device);
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 	if (res < 0)
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 		return res;
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-
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 	root_swap = res;
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-	res = blkdev_get(hib_resume_bdev, FMODE_WRITE, NULL);
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-	if (res)
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-		return res;
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+
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+	hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device, FMODE_WRITE,
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+			NULL);
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+	if (IS_ERR(hib_resume_bdev))
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+		return PTR_ERR(hib_resume_bdev);
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 	res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
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 	if (res < 0)
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 		blkdev_put(hib_resume_bdev, FMODE_WRITE);
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-	/*
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-	 * Update the resume device to the one actually used,
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-	 * so the test_resume mode can use it in case it is
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-	 * invoked from hibernate() to test the snapshot.
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-	 */
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-	swsusp_resume_device = hib_resume_bdev->bd_dev;
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 	return res;
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 }
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@@ -563,6 +569,7 @@
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 		nr_pages++;
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 	}
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 	err2 = hib_wait_io(&hb);
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+	hib_finish_batch(&hb);
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 	stop = ktime_get();
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 	if (!ret)
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 		ret = err2;
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@@ -856,6 +863,7 @@
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 		pr_info("Image saving done\n");
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 	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
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 out_clean:
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+	hib_finish_batch(&hb);
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 	if (crc) {
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 		if (crc->thr)
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 			kthread_stop(crc->thr);
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@@ -976,12 +984,11 @@
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 	last = handle->maps = NULL;
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 	offset = swsusp_header->image;
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 	while (offset) {
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-		tmp = kmalloc(sizeof(*handle->maps), GFP_KERNEL);
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+		tmp = kzalloc(sizeof(*handle->maps), GFP_KERNEL);
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 		if (!tmp) {
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 			release_swap_reader(handle);
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 			return -ENOMEM;
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 		}
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-		memset(tmp, 0, sizeof(*tmp));
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 		if (!handle->maps)
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 			handle->maps = tmp;
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 		if (last)
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@@ -1087,6 +1094,7 @@
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 		nr_pages++;
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 	}
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 	err2 = hib_wait_io(&hb);
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+	hib_finish_batch(&hb);
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 	stop = ktime_get();
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 	if (!ret)
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 		ret = err2;
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@@ -1450,6 +1458,7 @@
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 	}
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 	swsusp_show_speed(start, stop, nr_to_read, "Read");
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 out_clean:
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+	hib_finish_batch(&hb);
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 	for (i = 0; i < ring_size; i++)
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 		free_page((unsigned long)page[i]);
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 	if (crc) {
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@@ -1594,7 +1603,7 @@
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 }
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 #endif
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-static int swsusp_header_init(void)
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+static int __init swsusp_header_init(void)
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 {
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 	swsusp_header = (struct swsusp_header*) __get_free_page(GFP_KERNEL);
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 	if (!swsusp_header)