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2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc 
 kernel/drivers/mtd/mtdsuper.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /* MTD-based superblock management
23  *
34  * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
....@@ -5,11 +6,6 @@
56  *
67  * Written by:  David Howells <dhowells@redhat.com>
78  *              David Woodhouse <dwmw2@infradead.org>
8
- *
9
- * This program is free software; you can redistribute it and/or
10
- * modify it under the terms of the GNU General Public License
11
- * as published by the Free Software Foundation; either version
12
- * 2 of the License, or (at your option) any later version.
139  */
1410 
1511 #include <linux/mtd/super.h>
....@@ -19,112 +15,109 @@
1915 #include <linux/slab.h>
2016 #include <linux/major.h>
2117 #include <linux/backing-dev.h>
18
+#include <linux/fs_context.h>
19
+#include "mtdcore.h"
2220 
2321 /*
2422  * compare superblocks to see if they're equivalent
2523  * - they are if the underlying MTD device is the same
2624  */
27
-static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
25
+static int mtd_test_super(struct super_block *sb, struct fs_context *fc)
2826 {
29
-	struct mtd_info *mtd = _mtd;
27
+	struct mtd_info *mtd = fc->sget_key;
3028 
31
-	if (sb->s_mtd == mtd) {
29
+	if (sb->s_mtd == fc->sget_key) {
3230 		pr_debug("MTDSB: Match on device %d (\"%s\")\n",
33
-		      mtd->index, mtd->name);
31
+			 mtd->index, mtd->name);
3432 		return 1;
3533 	}
3634 
3735 	pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
38
-	      sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
36
+		 sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
3937 	return 0;
4038 }
41
-
42
-extern struct backing_dev_info *mtd_bdi;
4339 
4440 /*
4541  * mark the superblock by the MTD device it is using
4642  * - set the device number to be the correct MTD block device for pesuperstence
4743  *   of NFS exports
4844  */
49
-static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
45
+static int mtd_set_super(struct super_block *sb, struct fs_context *fc)
5046 {
51
-	struct mtd_info *mtd = _mtd;
52
-
53
-	sb->s_mtd = mtd;
54
-	sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
47
+	sb->s_mtd = fc->sget_key;
48
+	sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, sb->s_mtd->index);
5549 	sb->s_bdi = bdi_get(mtd_bdi);
56
-
5750 	return 0;
5851 }
5952 
6053 /*
6154  * get a superblock on an MTD-backed filesystem
6255  */
63
-static struct dentry *mount_mtd_aux(struct file_system_type *fs_type, int flags,
64
-			  const char *dev_name, void *data,
65
-			  struct mtd_info *mtd,
66
-			  int (*fill_super)(struct super_block *, void *, int))
56
+static int mtd_get_sb(struct fs_context *fc,
57
+		      struct mtd_info *mtd,
58
+		      int (*fill_super)(struct super_block *,
59
+					struct fs_context *))
6760 {
6861 	struct super_block *sb;
6962 	int ret;
7063 
71
-	sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, flags, mtd);
64
+	fc->sget_key = mtd;
65
+	sb = sget_fc(fc, mtd_test_super, mtd_set_super);
7266 	if (IS_ERR(sb))
73
-		goto out_error;
67
+		return PTR_ERR(sb);
7468 
75
-	if (sb->s_root)
76
-		goto already_mounted;
69
+	if (sb->s_root) {
70
+		/* new mountpoint for an already mounted superblock */
71
+		pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n",
72
+			 mtd->index, mtd->name);
73
+		put_mtd_device(mtd);
74
+	} else {
75
+		/* fresh new superblock */
76
+		pr_debug("MTDSB: New superblock for device %d (\"%s\")\n",
77
+			 mtd->index, mtd->name);
7778 
78
-	/* fresh new superblock */
79
-	pr_debug("MTDSB: New superblock for device %d (\"%s\")\n",
80
-	      mtd->index, mtd->name);
79
+		ret = fill_super(sb, fc);
80
+		if (ret < 0)
81
+			goto error_sb;
8182 
82
-	ret = fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
83
-	if (ret < 0) {
84
-		deactivate_locked_super(sb);
85
-		return ERR_PTR(ret);
83
+		sb->s_flags |= SB_ACTIVE;
8684 	}
8785 
88
-	/* go */
89
-	sb->s_flags |= SB_ACTIVE;
90
-	return dget(sb->s_root);
86
+	BUG_ON(fc->root);
87
+	fc->root = dget(sb->s_root);
88
+	return 0;
9189 
92
-	/* new mountpoint for an already mounted superblock */
93
-already_mounted:
94
-	pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n",
95
-	      mtd->index, mtd->name);
96
-	put_mtd_device(mtd);
97
-	return dget(sb->s_root);
98
-
99
-out_error:
100
-	put_mtd_device(mtd);
101
-	return ERR_CAST(sb);
90
+error_sb:
91
+	deactivate_locked_super(sb);
92
+	return ret;
10293 }
10394 
10495 /*
10596  * get a superblock on an MTD-backed filesystem by MTD device number
10697  */
107
-static struct dentry *mount_mtd_nr(struct file_system_type *fs_type, int flags,
108
-			 const char *dev_name, void *data, int mtdnr,
109
-			 int (*fill_super)(struct super_block *, void *, int))
98
+static int mtd_get_sb_by_nr(struct fs_context *fc, int mtdnr,
99
+			    int (*fill_super)(struct super_block *,
100
+					      struct fs_context *))
110101 {
111102 	struct mtd_info *mtd;
112103 
113104 	mtd = get_mtd_device(NULL, mtdnr);
114105 	if (IS_ERR(mtd)) {
115
-		pr_debug("MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
116
-		return ERR_CAST(mtd);
106
+		errorf(fc, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
107
+		return PTR_ERR(mtd);
117108 	}
118109 
119
-	return mount_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super);
110
+	return mtd_get_sb(fc, mtd, fill_super);
120111 }
121112 
122
-/*
123
- * set up an MTD-based superblock
113
+/**
114
+ * get_tree_mtd - Get a superblock based on a single MTD device
115
+ * @fc: The filesystem context holding the parameters
116
+ * @fill_super: Helper to initialise a new superblock
124117  */
125
-struct dentry *mount_mtd(struct file_system_type *fs_type, int flags,
126
-	       const char *dev_name, void *data,
127
-	       int (*fill_super)(struct super_block *, void *, int))
118
+int get_tree_mtd(struct fs_context *fc,
119
+	      int (*fill_super)(struct super_block *sb,
120
+				struct fs_context *fc))
128121 {
129122 #ifdef CONFIG_BLOCK
130123 	struct block_device *bdev;
....@@ -132,46 +125,42 @@
132125 #endif
133126 	int mtdnr;
134127 
135
-	if (!dev_name)
136
-		return ERR_PTR(-EINVAL);
128
+	if (!fc->source)
129
+		return invalf(fc, "No source specified");
137130 
138
-	pr_debug("MTDSB: dev_name \"%s\"\n", dev_name);
131
+	pr_debug("MTDSB: dev_name \"%s\"\n", fc->source);
139132 
140133 	/* the preferred way of mounting in future; especially when
141134 	 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
142135 	 * by name, so that we don't require block device support to be present
143
-	 * in the kernel. */
144
-	if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
145
-		if (dev_name[3] == ':') {
136
+	 * in the kernel.
137
+	 */
138
+	if (fc->source[0] == 'm' &&
139
+	    fc->source[1] == 't' &&
140
+	    fc->source[2] == 'd') {
141
+		if (fc->source[3] == ':') {
146142 			struct mtd_info *mtd;
147143 
148144 			/* mount by MTD device name */
149145 			pr_debug("MTDSB: mtd:%%s, name \"%s\"\n",
150
-			      dev_name + 4);
146
+				 fc->source + 4);
151147 
152
-			mtd = get_mtd_device_nm(dev_name + 4);
148
+			mtd = get_mtd_device_nm(fc->source + 4);
153149 			if (!IS_ERR(mtd))
154
-				return mount_mtd_aux(
155
-					fs_type, flags,
156
-					dev_name, data, mtd,
157
-					fill_super);
150
+				return mtd_get_sb(fc, mtd, fill_super);
158151 
159
-			printk(KERN_NOTICE "MTD:"
160
-			       " MTD device with name \"%s\" not found.\n",
161
-			       dev_name + 4);
152
+			errorf(fc, "MTD: MTD device with name \"%s\" not found",
153
+			       fc->source + 4);
162154 
163
-		} else if (isdigit(dev_name[3])) {
155
+		} else if (isdigit(fc->source[3])) {
164156 			/* mount by MTD device number name */
165157 			char *endptr;
166158 
167
-			mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
159
+			mtdnr = simple_strtoul(fc->source + 3, &endptr, 0);
168160 			if (!*endptr) {
169161 				/* It was a valid number */
170
-				pr_debug("MTDSB: mtd%%d, mtdnr %d\n",
171
-				      mtdnr);
172
-				return mount_mtd_nr(fs_type, flags,
173
-						     dev_name, data,
174
-						     mtdnr, fill_super);
162
+				pr_debug("MTDSB: mtd%%d, mtdnr %d\n", mtdnr);
163
+				return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
175164 			}
176165 		}
177166 	}
....@@ -180,36 +169,29 @@
180169 	/* try the old way - the hack where we allowed users to mount
181170 	 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
182171 	 */
183
-	bdev = lookup_bdev(dev_name);
172
+	bdev = lookup_bdev(fc->source);
184173 	if (IS_ERR(bdev)) {
185174 		ret = PTR_ERR(bdev);
186
-		pr_debug("MTDSB: lookup_bdev() returned %d\n", ret);
187
-		return ERR_PTR(ret);
175
+		errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
176
+		return ret;
188177 	}
189178 	pr_debug("MTDSB: lookup_bdev() returned 0\n");
190
-
191
-	ret = -EINVAL;
192179 
193180 	major = MAJOR(bdev->bd_dev);
194181 	mtdnr = MINOR(bdev->bd_dev);
195182 	bdput(bdev);
196183 
197
-	if (major != MTD_BLOCK_MAJOR)
198
-		goto not_an_MTD_device;
184
+	if (major == MTD_BLOCK_MAJOR)
185
+		return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
199186 
200
-	return mount_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super);
201
-
202
-not_an_MTD_device:
203187 #endif /* CONFIG_BLOCK */
204188 
205
-	if (!(flags & SB_SILENT))
206
-		printk(KERN_NOTICE
207
-		       "MTD: Attempt to mount non-MTD device \"%s\"\n",
208
-		       dev_name);
209
-	return ERR_PTR(-EINVAL);
189
+	if (!(fc->sb_flags & SB_SILENT))
190
+		errorf(fc, "MTD: Attempt to mount non-MTD device \"%s\"",
191
+		       fc->source);
192
+	return -EINVAL;
210193 }
211
-
212
-EXPORT_SYMBOL_GPL(mount_mtd);
194
+EXPORT_SYMBOL_GPL(get_tree_mtd);
213195 
214196 /*
215197  * destroy an MTD-based superblock