1 files changed, 7 insertions, 31 deletions

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1600034a929b..31219c1db17d 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -6,6 +6,8 @@
  * initial implementation -- AV, Oct 2001.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/cache.h>
 #include <linux/fs.h>
 #include <linux/export.h>
@@ -68,13 +70,6 @@ int seq_open(struct file *file, const struct seq_operations *op)
 	p->file = file;
 
 	/*
-	 * Wrappers around seq_open(e.g. swaps_open) need to be
-	 * aware of this. If they set f_version themselves, they
-	 * should call seq_open first and then set f_version.
-	 */
-	file->f_version = 0;
-
-	/*
 	 * seq_files support lseek() and pread().  They do not implement
 	 * write() at all, but we clear FMODE_PWRITE here for historical
 	 * reasons.
@@ -94,7 +89,6 @@ static int traverse(struct seq_file *m, loff_t offset)
 	int error = 0;
 	void *p;
 
-	m->version = 0;
 	m->index = 0;
 	m->count = m->from = 0;
 	if (!offset)
@@ -161,25 +155,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	mutex_lock(&m->lock);
 
 	/*
-	 * seq_file->op->..m_start/m_stop/m_next may do special actions
-	 * or optimisations based on the file->f_version, so we want to
-	 * pass the file->f_version to those methods.
-	 *
-	 * seq_file->version is just copy of f_version, and seq_file
-	 * methods can treat it simply as file version.
-	 * It is copied in first and copied out after all operations.
-	 * It is convenient to have it as  part of structure to avoid the
-	 * need of passing another argument to all the seq_file methods.
-	 */
-	m->version = file->f_version;
-
-	/*
 	 * if request is to read from zero offset, reset iterator to first
 	 * record as it might have been already advanced by previous requests
 	 */
 	if (*ppos == 0) {
 		m->index = 0;
-		m->version = 0;
 		m->count = 0;
 	}
 
@@ -190,7 +170,6 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 		if (err) {
 			/* With prejudice... */
 			m->read_pos = 0;
-			m->version = 0;
 			m->index = 0;
 			m->count = 0;
 			goto Done;
@@ -243,7 +222,6 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 		m->buf = seq_buf_alloc(m->size <<= 1);
 		if (!m->buf)
 			goto Enomem;
-		m->version = 0;
 		p = m->op->start(m, &m->index);
 	}
 	m->op->stop(m, p);
@@ -256,9 +234,11 @@ Fill:
 		loff_t pos = m->index;
 
 		p = m->op->next(m, p, &m->index);
-		if (pos == m->index)
-			/* Buggy ->next function */
+		if (pos == m->index) {
+			pr_info_ratelimited("buggy .next function %ps did not update position index\n",
+					    m->op->next);
 			m->index++;
+		}
 		if (!p || IS_ERR(p)) {
 			err = PTR_ERR(p);
 			break;
@@ -287,7 +267,6 @@ Done:
 		*ppos += copied;
 		m->read_pos += copied;
 	}
-	file->f_version = m->version;
 	mutex_unlock(&m->lock);
 	return copied;
 Enomem:
@@ -313,11 +292,10 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
 	loff_t retval = -EINVAL;
 
 	mutex_lock(&m->lock);
-	m->version = file->f_version;
 	switch (whence) {
 	case SEEK_CUR:
 		offset += file->f_pos;
-		/* fall through */
+		fallthrough;
 	case SEEK_SET:
 		if (offset < 0)
 			break;
@@ -329,7 +307,6 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
 				/* with extreme prejudice... */
 				file->f_pos = 0;
 				m->read_pos = 0;
-				m->version = 0;
 				m->index = 0;
 				m->count = 0;
 			} else {
@@ -340,7 +317,6 @@ loff_t seq_lseek(struct file *file, loff_t offset, int whence)
 			file->f_pos = offset;
 		}
 	}
-	file->f_version = m->version;
 	mutex_unlock(&m->lock);
 	return retval;
 }