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2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376 
 kernel/fs/kernfs/file.c
....@@ -1,11 +1,10 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * fs/kernfs/file.c - kernfs file implementation
34  *
45  * Copyright (c) 2001-3 Patrick Mochel
56  * Copyright (c) 2007 SUSE Linux Products GmbH
67  * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
7
- *
8
- * This file is released under the GPLv2.
98  */
109 
1110 #include <linux/fs.h>
....@@ -15,6 +14,7 @@
1514 #include <linux/pagemap.h>
1615 #include <linux/sched/mm.h>
1716 #include <linux/fsnotify.h>
17
+#include <linux/uio.h>
1818 
1919 #include "kernfs-internal.h"
2020 
....@@ -181,11 +181,10 @@
181181  * it difficult to use seq_file.  Implement simplistic custom buffering for
182182  * bin files.
183183  */
184
-static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,
185
-				       char __user *user_buf, size_t count,
186
-				       loff_t *ppos)
184
+static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
187185 {
188
-	ssize_t len = min_t(size_t, count, PAGE_SIZE);
186
+	struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);
187
+	ssize_t len = min_t(size_t, iov_iter_count(iter), PAGE_SIZE);
189188 	const struct kernfs_ops *ops;
190189 	char *buf;
191190 
....@@ -211,7 +210,7 @@
211210 	of->event = atomic_read(&of->kn->attr.open->event);
212211 	ops = kernfs_ops(of->kn);
213212 	if (ops->read)
214
-		len = ops->read(of, buf, len, *ppos);
213
+		len = ops->read(of, buf, len, iocb->ki_pos);
215214 	else
216215 		len = -EINVAL;
217216 
....@@ -221,12 +220,12 @@
221220 	if (len < 0)
222221 		goto out_free;
223222 
224
-	if (copy_to_user(user_buf, buf, len)) {
223
+	if (copy_to_iter(buf, len, iter) != len) {
225224 		len = -EFAULT;
226225 		goto out_free;
227226 	}
228227 
229
-	*ppos += len;
228
+	iocb->ki_pos += len;
230229 
231230  out_free:
232231 	if (buf == of->prealloc_buf)
....@@ -236,31 +235,14 @@
236235 	return len;
237236 }
238237 
239
-/**
240
- * kernfs_fop_read - kernfs vfs read callback
241
- * @file: file pointer
242
- * @user_buf: data to write
243
- * @count: number of bytes
244
- * @ppos: starting offset
245
- */
246
-static ssize_t kernfs_fop_read(struct file *file, char __user *user_buf,
247
-			       size_t count, loff_t *ppos)
238
+static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter)
248239 {
249
-	struct kernfs_open_file *of = kernfs_of(file);
250
-
251
-	if (of->kn->flags & KERNFS_HAS_SEQ_SHOW)
252
-		return seq_read(file, user_buf, count, ppos);
253
-	else
254
-		return kernfs_file_direct_read(of, user_buf, count, ppos);
240
+	if (kernfs_of(iocb->ki_filp)->kn->flags & KERNFS_HAS_SEQ_SHOW)
241
+		return seq_read_iter(iocb, iter);
242
+	return kernfs_file_read_iter(iocb, iter);
255243 }
256244 
257
-/**
258
- * kernfs_fop_write - kernfs vfs write callback
259
- * @file: file pointer
260
- * @user_buf: data to write
261
- * @count: number of bytes
262
- * @ppos: starting offset
263
- *
245
+/*
264246  * Copy data in from userland and pass it to the matching kernfs write
265247  * operation.
266248  *
....@@ -270,20 +252,18 @@
270252  * modify only the the value you're changing, then write entire buffer
271253  * back.
272254  */
273
-static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
274
-				size_t count, loff_t *ppos)
255
+static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
275256 {
276
-	struct kernfs_open_file *of = kernfs_of(file);
257
+	struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);
258
+	ssize_t len = iov_iter_count(iter);
277259 	const struct kernfs_ops *ops;
278
-	ssize_t len;
279260 	char *buf;
280261 
281262 	if (of->atomic_write_len) {
282
-		len = count;
283263 		if (len > of->atomic_write_len)
284264 			return -E2BIG;
285265 	} else {
286
-		len = min_t(size_t, count, PAGE_SIZE);
266
+		len = min_t(size_t, len, PAGE_SIZE);
287267 	}
288268 
289269 	buf = of->prealloc_buf;
....@@ -294,7 +274,7 @@
294274 	if (!buf)
295275 		return -ENOMEM;
296276 
297
-	if (copy_from_user(buf, user_buf, len)) {
277
+	if (copy_from_iter(buf, len, iter) != len) {
298278 		len = -EFAULT;
299279 		goto out_free;
300280 	}
....@@ -313,7 +293,7 @@
313293 
314294 	ops = kernfs_ops(of->kn);
315295 	if (ops->write)
316
-		len = ops->write(of, buf, len, *ppos);
296
+		len = ops->write(of, buf, len, iocb->ki_pos);
317297 	else
318298 		len = -EINVAL;
319299 
....@@ -321,7 +301,7 @@
321301 	mutex_unlock(&of->mutex);
322302 
323303 	if (len > 0)
324
-		*ppos += len;
304
+		iocb->ki_pos += len;
325305 
326306 out_free:
327307 	if (buf == of->prealloc_buf)
....@@ -653,9 +633,9 @@
653633 	 * The following is done to give a different lockdep key to
654634 	 * @of->mutex for files which implement mmap.  This is a rather
655635 	 * crude way to avoid false positive lockdep warning around
656
-	 * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and
636
+	 * mm->mmap_lock - mmap nests @of->mutex under mm->mmap_lock and
657637 	 * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under
658
-	 * which mm->mmap_sem nests, while holding @of->mutex.  As each
638
+	 * which mm->mmap_lock nests, while holding @of->mutex.  As each
659639 	 * open file has a separate mutex, it's okay as long as those don't
660640 	 * happen on the same file.  At this point, we can't easily give
661641 	 * each file a separate locking class.  Let's differentiate on
....@@ -674,7 +654,7 @@
674654 
675655 	/*
676656 	 * Write path needs to atomic_write_len outside active reference.
677
-	 * Cache it in open_file.  See kernfs_fop_write() for details.
657
+	 * Cache it in open_file.  See kernfs_fop_write_iter() for details.
678658 	 */
679659 	of->atomic_write_len = ops->atomic_write_len;
680660 
....@@ -884,7 +864,9 @@
884864 
885865 	list_for_each_entry(info, &kernfs_root(kn)->supers, node) {
886866 		struct kernfs_node *parent;
867
+		struct inode *p_inode = NULL;
887868 		struct inode *inode;
869
+		struct qstr name;
888870 
889871 		/*
890872 		 * We want fsnotify_modify() on @kn but as the
....@@ -892,26 +874,27 @@
892874 		 * have the matching @file available.  Look up the inodes
893875 		 * and generate the events manually.
894876 		 */
895
-		inode = ilookup(info->sb, kn->id.ino);
877
+		inode = ilookup(info->sb, kernfs_ino(kn));
896878 		if (!inode)
897879 			continue;
898880 
881
+		name = (struct qstr)QSTR_INIT(kn->name, strlen(kn->name));
899882 		parent = kernfs_get_parent(kn);
900883 		if (parent) {
901
-			struct inode *p_inode;
902
-
903
-			p_inode = ilookup(info->sb, parent->id.ino);
884
+			p_inode = ilookup(info->sb, kernfs_ino(parent));
904885 			if (p_inode) {
905
-				fsnotify(p_inode, FS_MODIFY | FS_EVENT_ON_CHILD,
906
-					 inode, FSNOTIFY_EVENT_INODE, kn->name, 0);
886
+				fsnotify(FS_MODIFY | FS_EVENT_ON_CHILD,
887
+					 inode, FSNOTIFY_EVENT_INODE,
888
+					 p_inode, &name, inode, 0);
907889 				iput(p_inode);
908890 			}
909891 
910892 			kernfs_put(parent);
911893 		}
912894 
913
-		fsnotify(inode, FS_MODIFY, inode, FSNOTIFY_EVENT_INODE,
914
-			 kn->name, 0);
895
+		if (!p_inode)
896
+			fsnotify_inode(inode, FS_MODIFY);
897
+
915898 		iput(inode);
916899 	}
917900 
....@@ -958,14 +941,16 @@
958941 EXPORT_SYMBOL_GPL(kernfs_notify);
959942 
960943 const struct file_operations kernfs_file_fops = {
961
-	.read		= kernfs_fop_read,
962
-	.write		= kernfs_fop_write,
944
+	.read_iter	= kernfs_fop_read_iter,
945
+	.write_iter	= kernfs_fop_write_iter,
963946 	.llseek		= generic_file_llseek,
964947 	.mmap		= kernfs_fop_mmap,
965948 	.open		= kernfs_fop_open,
966949 	.release	= kernfs_fop_release,
967950 	.poll		= kernfs_fop_poll,
968951 	.fsync		= noop_fsync,
952
+	.splice_read	= generic_file_splice_read,
953
+	.splice_write	= iter_file_splice_write,
969954 };
970955 
971956 /**
....@@ -1009,7 +994,7 @@
1009994 
1010995 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1011996 	if (key) {
1012
-		lockdep_init_map(&kn->dep_map, "kn->count", key, 0);
997
+		lockdep_init_map(&kn->dep_map, "kn->active", key, 0);
1013998 		kn->flags |= KERNFS_LOCKDEP;
1014999 	}
10151000 #endif