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2024-05-10 37f49e37ab4cb5d0bc4c60eb5c6d4dd57db767bb 
 kernel/drivers/dax/super.c
....@@ -1,18 +1,11 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * Copyright(c) 2017 Intel Corporation. All rights reserved.
3
- *
4
- * This program is free software; you can redistribute it and/or modify
5
- * it under the terms of version 2 of the GNU General Public License as
6
- * published by the Free Software Foundation.
7
- *
8
- * This program is distributed in the hope that it will be useful, but
9
- * WITHOUT ANY WARRANTY; without even the implied warranty of
10
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11
- * General Public License for more details.
124  */
135 #include <linux/pagemap.h>
146 #include <linux/module.h>
157 #include <linux/mount.h>
8
+#include <linux/pseudo_fs.h>
169 #include <linux/magic.h>
1710 #include <linux/genhd.h>
1811 #include <linux/pfn_t.h>
....@@ -22,6 +15,7 @@
2215 #include <linux/uio.h>
2316 #include <linux/dax.h>
2417 #include <linux/fs.h>
18
+#include "dax-private.h"
2519 
2620 static dev_t dax_devt;
2721 DEFINE_STATIC_SRCU(dax_srcu);
....@@ -52,7 +46,8 @@
5246 int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
5347 		pgoff_t *pgoff)
5448 {
55
-	phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512;
49
+	sector_t start_sect = bdev ? get_start_sect(bdev) : 0;
50
+	phys_addr_t phys_off = (start_sect + sector) * 512;
5651 
5752 	if (pgoff)
5853 		*pgoff = PHYS_PFN(phys_off);
....@@ -65,70 +60,61 @@
6560 #if IS_ENABLED(CONFIG_FS_DAX)
6661 struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
6762 {
68
-	if (!blk_queue_dax(bdev->bd_queue))
63
+	if (!blk_queue_dax(bdev->bd_disk->queue))
6964 		return NULL;
70
-	return fs_dax_get_by_host(bdev->bd_disk->disk_name);
65
+	return dax_get_by_host(bdev->bd_disk->disk_name);
7166 }
7267 EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev);
7368 #endif
7469 
75
-/**
76
- * __bdev_dax_supported() - Check if the device supports dax for filesystem
77
- * @bdev: block device to check
78
- * @blocksize: The block size of the device
79
- *
80
- * This is a library function for filesystems to check if the block device
81
- * can be mounted with dax option.
82
- *
83
- * Return: true if supported, false if unsupported
84
- */
85
-bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
70
+bool __generic_fsdax_supported(struct dax_device *dax_dev,
71
+		struct block_device *bdev, int blocksize, sector_t start,
72
+		sector_t sectors)
8673 {
87
-	struct dax_device *dax_dev;
8874 	bool dax_enabled = false;
89
-	struct request_queue *q;
90
-	pgoff_t pgoff;
91
-	int err, id;
92
-	pfn_t pfn;
93
-	long len;
75
+	pgoff_t pgoff, pgoff_end;
9476 	char buf[BDEVNAME_SIZE];
77
+	void *kaddr, *end_kaddr;
78
+	pfn_t pfn, end_pfn;
79
+	sector_t last_page;
80
+	long len, len2;
81
+	int err, id;
9582 
9683 	if (blocksize != PAGE_SIZE) {
97
-		pr_debug("%s: error: unsupported blocksize for dax\n",
84
+		pr_info("%s: error: unsupported blocksize for dax\n",
9885 				bdevname(bdev, buf));
9986 		return false;
10087 	}
10188 
102
-	q = bdev_get_queue(bdev);
103
-	if (!q || !blk_queue_dax(q)) {
104
-		pr_debug("%s: error: request queue doesn't support dax\n",
105
-				bdevname(bdev, buf));
106
-		return false;
107
-	}
108
-
109
-	err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff);
110
-	if (err) {
111
-		pr_debug("%s: error: unaligned partition for dax\n",
112
-				bdevname(bdev, buf));
113
-		return false;
114
-	}
115
-
116
-	dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
11789 	if (!dax_dev) {
118
-		pr_debug("%s: error: device does not support dax\n",
90
+		pr_debug("%s: error: dax unsupported by block device\n",
91
+				bdevname(bdev, buf));
92
+		return false;
93
+	}
94
+
95
+	err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
96
+	if (err) {
97
+		pr_info("%s: error: unaligned partition for dax\n",
98
+				bdevname(bdev, buf));
99
+		return false;
100
+	}
101
+
102
+	last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512;
103
+	err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
104
+	if (err) {
105
+		pr_info("%s: error: unaligned partition for dax\n",
119106 				bdevname(bdev, buf));
120107 		return false;
121108 	}
122109 
123110 	id = dax_read_lock();
124
-	len = dax_direct_access(dax_dev, pgoff, 1, NULL, &pfn);
125
-	dax_read_unlock(id);
111
+	len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
112
+	len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
126113 
127
-	put_dax(dax_dev);
128
-
129
-	if (len < 1) {
130
-		pr_debug("%s: error: dax access failed (%ld)\n",
131
-				bdevname(bdev, buf), len);
114
+	if (len < 1 || len2 < 1) {
115
+		pr_info("%s: error: dax access failed (%ld)\n",
116
+				bdevname(bdev, buf), len < 1 ? len : len2);
117
+		dax_read_unlock(id);
132118 		return false;
133119 	}
134120 
....@@ -143,21 +129,72 @@
143129 		 */
144130 		WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
145131 		dax_enabled = true;
146
-	} else if (pfn_t_devmap(pfn)) {
147
-		struct dev_pagemap *pgmap;
132
+	} else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) {
133
+		struct dev_pagemap *pgmap, *end_pgmap;
148134 
149135 		pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL);
150
-		if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX)
136
+		end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL);
137
+		if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX
138
+				&& pfn_t_to_page(pfn)->pgmap == pgmap
139
+				&& pfn_t_to_page(end_pfn)->pgmap == pgmap
140
+				&& pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr))
141
+				&& pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr)))
151142 			dax_enabled = true;
152143 		put_dev_pagemap(pgmap);
144
+		put_dev_pagemap(end_pgmap);
145
+
153146 	}
147
+	dax_read_unlock(id);
154148 
155149 	if (!dax_enabled) {
156
-		pr_debug("%s: error: dax support not enabled\n",
150
+		pr_info("%s: error: dax support not enabled\n",
157151 				bdevname(bdev, buf));
158152 		return false;
159153 	}
160154 	return true;
155
+}
156
+EXPORT_SYMBOL_GPL(__generic_fsdax_supported);
157
+
158
+/**
159
+ * __bdev_dax_supported() - Check if the device supports dax for filesystem
160
+ * @bdev: block device to check
161
+ * @blocksize: The block size of the device
162
+ *
163
+ * This is a library function for filesystems to check if the block device
164
+ * can be mounted with dax option.
165
+ *
166
+ * Return: true if supported, false if unsupported
167
+ */
168
+bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
169
+{
170
+	struct dax_device *dax_dev;
171
+	struct request_queue *q;
172
+	char buf[BDEVNAME_SIZE];
173
+	bool ret;
174
+	int id;
175
+
176
+	q = bdev_get_queue(bdev);
177
+	if (!q || !blk_queue_dax(q)) {
178
+		pr_debug("%s: error: request queue doesn't support dax\n",
179
+				bdevname(bdev, buf));
180
+		return false;
181
+	}
182
+
183
+	dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
184
+	if (!dax_dev) {
185
+		pr_debug("%s: error: device does not support dax\n",
186
+				bdevname(bdev, buf));
187
+		return false;
188
+	}
189
+
190
+	id = dax_read_lock();
191
+	ret = dax_supported(dax_dev, bdev, blocksize, 0,
192
+			i_size_read(bdev->bd_inode) / 512);
193
+	dax_read_unlock(id);
194
+
195
+	put_dax(dax_dev);
196
+
197
+	return ret;
161198 }
162199 EXPORT_SYMBOL_GPL(__bdev_dax_supported);
163200 #endif
....@@ -167,6 +204,8 @@
167204 	DAXDEV_ALIVE,
168205 	/* gate whether dax_flush() calls the low level flush routine */
169206 	DAXDEV_WRITE_CACHE,
207
+	/* flag to check if device supports synchronous flush */
208
+	DAXDEV_SYNC,
170209 };
171210 
172211 /**
....@@ -284,6 +323,19 @@
284323 }
285324 EXPORT_SYMBOL_GPL(dax_direct_access);
286325 
326
+bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
327
+		int blocksize, sector_t start, sector_t len)
328
+{
329
+	if (!dax_dev)
330
+		return false;
331
+
332
+	if (!dax_alive(dax_dev))
333
+		return false;
334
+
335
+	return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
336
+}
337
+EXPORT_SYMBOL_GPL(dax_supported);
338
+
287339 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
288340 		size_t bytes, struct iov_iter *i)
289341 {
....@@ -303,6 +355,23 @@
303355 	return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i);
304356 }
305357 EXPORT_SYMBOL_GPL(dax_copy_to_iter);
358
+
359
+int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
360
+			size_t nr_pages)
361
+{
362
+	if (!dax_alive(dax_dev))
363
+		return -ENXIO;
364
+	/*
365
+	 * There are no callers that want to zero more than one page as of now.
366
+	 * Once users are there, this check can be removed after the
367
+	 * device mapper code has been updated to split ranges across targets.
368
+	 */
369
+	if (nr_pages != 1)
370
+		return -EIO;
371
+
372
+	return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages);
373
+}
374
+EXPORT_SYMBOL_GPL(dax_zero_page_range);
306375 
307376 #ifdef CONFIG_ARCH_HAS_PMEM_API
308377 void arch_wb_cache_pmem(void *addr, size_t size);
....@@ -335,6 +404,18 @@
335404 }
336405 EXPORT_SYMBOL_GPL(dax_write_cache_enabled);
337406 
407
+bool __dax_synchronous(struct dax_device *dax_dev)
408
+{
409
+	return test_bit(DAXDEV_SYNC, &dax_dev->flags);
410
+}
411
+EXPORT_SYMBOL_GPL(__dax_synchronous);
412
+
413
+void __set_dax_synchronous(struct dax_device *dax_dev)
414
+{
415
+	set_bit(DAXDEV_SYNC, &dax_dev->flags);
416
+}
417
+EXPORT_SYMBOL_GPL(__set_dax_synchronous);
418
+
338419 bool dax_alive(struct dax_device *dax_dev)
339420 {
340421 	lockdep_assert_held(&dax_srcu);
....@@ -365,10 +446,14 @@
365446 	spin_lock(&dax_host_lock);
366447 	hlist_del_init(&dax_dev->list);
367448 	spin_unlock(&dax_host_lock);
368
-
369
-	dax_dev->private = NULL;
370449 }
371450 EXPORT_SYMBOL_GPL(kill_dax);
451
+
452
+void run_dax(struct dax_device *dax_dev)
453
+{
454
+	set_bit(DAXDEV_ALIVE, &dax_dev->flags);
455
+}
456
+EXPORT_SYMBOL_GPL(run_dax);
372457 
373458 static struct inode *dax_alloc_inode(struct super_block *sb)
374459 {
....@@ -389,11 +474,9 @@
389474 	return container_of(inode, struct dax_device, inode);
390475 }
391476 
392
-static void dax_i_callback(struct rcu_head *head)
477
+static void dax_free_inode(struct inode *inode)
393478 {
394
-	struct inode *inode = container_of(head, struct inode, i_rcu);
395479 	struct dax_device *dax_dev = to_dax_dev(inode);
396
-
397480 	kfree(dax_dev->host);
398481 	dax_dev->host = NULL;
399482 	if (inode->i_rdev)
....@@ -404,29 +487,31 @@
404487 static void dax_destroy_inode(struct inode *inode)
405488 {
406489 	struct dax_device *dax_dev = to_dax_dev(inode);
407
-
408490 	WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags),
409491 			"kill_dax() must be called before final iput()\n");
410
-	call_rcu(&inode->i_rcu, dax_i_callback);
411492 }
412493 
413494 static const struct super_operations dax_sops = {
414495 	.statfs = simple_statfs,
415496 	.alloc_inode = dax_alloc_inode,
416497 	.destroy_inode = dax_destroy_inode,
498
+	.free_inode = dax_free_inode,
417499 	.drop_inode = generic_delete_inode,
418500 };
419501 
420
-static struct dentry *dax_mount(struct file_system_type *fs_type,
421
-		int flags, const char *dev_name, void *data)
502
+static int dax_init_fs_context(struct fs_context *fc)
422503 {
423
-	return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC);
504
+	struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC);
505
+	if (!ctx)
506
+		return -ENOMEM;
507
+	ctx->ops = &dax_sops;
508
+	return 0;
424509 }
425510 
426511 static struct file_system_type dax_fs_type = {
427
-	.name = "dax",
428
-	.mount = dax_mount,
429
-	.kill_sb = kill_anon_super,
512
+	.name		= "dax",
513
+	.init_fs_context = dax_init_fs_context,
514
+	.kill_sb	= kill_anon_super,
430515 };
431516 
432517 static int dax_test(struct inode *inode, void *data)
....@@ -488,16 +573,23 @@
488573 }
489574 
490575 struct dax_device *alloc_dax(void *private, const char *__host,
491
-		const struct dax_operations *ops)
576
+		const struct dax_operations *ops, unsigned long flags)
492577 {
493578 	struct dax_device *dax_dev;
494579 	const char *host;
495580 	dev_t devt;
496581 	int minor;
497582 
583
+	if (ops && !ops->zero_page_range) {
584
+		pr_debug("%s: error: device does not provide dax"
585
+			 " operation zero_page_range()\n",
586
+			 __host ? __host : "Unknown");
587
+		return ERR_PTR(-EINVAL);
588
+	}
589
+
498590 	host = kstrdup(__host, GFP_KERNEL);
499591 	if (__host && !host)
500
-		return NULL;
592
+		return ERR_PTR(-ENOMEM);
501593 
502594 	minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL);
503595 	if (minor < 0)
....@@ -511,13 +603,16 @@
511603 	dax_add_host(dax_dev, host);
512604 	dax_dev->ops = ops;
513605 	dax_dev->private = private;
606
+	if (flags & DAXDEV_F_SYNC)
607
+		set_dax_synchronous(dax_dev);
608
+
514609 	return dax_dev;
515610 
516611  err_dev:
517612 	ida_simple_remove(&dax_minor_ida, minor);
518613  err_minor:
519614 	kfree(host);
520
-	return NULL;
615
+	return ERR_PTR(-ENOMEM);
521616 }
522617 EXPORT_SYMBOL_GPL(alloc_dax);
523618 
....@@ -584,6 +679,8 @@
584679 
585680 void *dax_get_private(struct dax_device *dax_dev)
586681 {
682
+	if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags))
683
+		return NULL;
587684 	return dax_dev->private;
588685 }
589686 EXPORT_SYMBOL_GPL(dax_get_private);
....@@ -597,7 +694,7 @@
597694 	inode_init_once(inode);
598695 }
599696 
600
-static int __dax_fs_init(void)
697
+static int dax_fs_init(void)
601698 {
602699 	int rc;
603700 
....@@ -607,10 +704,6 @@
607704 			init_once);
608705 	if (!dax_cache)
609706 		return -ENOMEM;
610
-
611
-	rc = register_filesystem(&dax_fs_type);
612
-	if (rc)
613
-		goto err_register_fs;
614707 
615708 	dax_mnt = kern_mount(&dax_fs_type);
616709 	if (IS_ERR(dax_mnt)) {
....@@ -622,42 +715,51 @@
622715 	return 0;
623716 
624717  err_mount:
625
-	unregister_filesystem(&dax_fs_type);
626
- err_register_fs:
627718 	kmem_cache_destroy(dax_cache);
628719 
629720 	return rc;
630721 }
631722 
632
-static void __dax_fs_exit(void)
723
+static void dax_fs_exit(void)
633724 {
634725 	kern_unmount(dax_mnt);
635
-	unregister_filesystem(&dax_fs_type);
726
+	rcu_barrier();
636727 	kmem_cache_destroy(dax_cache);
637728 }
638729 
639
-static int __init dax_fs_init(void)
730
+static int __init dax_core_init(void)
640731 {
641732 	int rc;
642733 
643
-	rc = __dax_fs_init();
734
+	rc = dax_fs_init();
644735 	if (rc)
645736 		return rc;
646737 
647738 	rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax");
648739 	if (rc)
649
-		__dax_fs_exit();
650
-	return rc;
740
+		goto err_chrdev;
741
+
742
+	rc = dax_bus_init();
743
+	if (rc)
744
+		goto err_bus;
745
+	return 0;
746
+
747
+err_bus:
748
+	unregister_chrdev_region(dax_devt, MINORMASK+1);
749
+err_chrdev:
750
+	dax_fs_exit();
751
+	return 0;
651752 }
652753 
653
-static void __exit dax_fs_exit(void)
754
+static void __exit dax_core_exit(void)
654755 {
756
+	dax_bus_exit();
655757 	unregister_chrdev_region(dax_devt, MINORMASK+1);
656758 	ida_destroy(&dax_minor_ida);
657
-	__dax_fs_exit();
759
+	dax_fs_exit();
658760 }
659761 
660762 MODULE_AUTHOR("Intel Corporation");
661763 MODULE_LICENSE("GPL v2");
662
-subsys_initcall(dax_fs_init);
663
-module_exit(dax_fs_exit);
764
+subsys_initcall(dax_core_init);
765
+module_exit(dax_core_exit);