[patch 099/166] seq_file: remove m->version

Andrew Morton
2020-04-07T03:09:21Z

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: seq_file: remove m->version

The process maps file was the only user of version (introduced back in
2005). Now that it uses ppos instead, we can remove it.

Link: http://lkml.kernel.org/r/20200317193201.9924-4-adobriyan@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

fs/seq_file.c | 28 ----------------------------
include/linux/seq_file.h | 1 -
2 files changed, 29 deletions(-)

--- a/fs/seq_file.c~seq_file-remove-m-version
+++ a/fs/seq_file.c
@@ -68,13 +68,6 @@ int seq_open(struct file *file, const st
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 +87,6 @@ static int traverse(struct seq_file *m,
int error = 0;
void *p;

- m->version = 0;
m->index = 0;
m->count = m->from = 0;
if (!offset)
@@ -161,25 +153,11 @@ ssize_t seq_read(struct file *file, char
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 +168,6 @@ ssize_t seq_read(struct file *file, char
if (err) {
/* With prejudice... */
m->read_pos = 0;
- m->version = 0;
m->index = 0;
m->count = 0;
goto Done;
@@ -243,7 +220,6 @@ ssize_t seq_read(struct file *file, char
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);
@@ -287,7 +263,6 @@ Done:
*ppos += copied;
m->read_pos += copied;
}
- file->f_version = m->version;
mutex_unlock(&m->lock);
return copied;
Enomem:
@@ -313,7 +288,6 @@ loff_t seq_lseek(struct file *file, loff
loff_t retval = -EINVAL;

mutex_lock(&m->lock);
- m->version = file->f_version;
switch (whence) {
case SEEK_CUR:
offset += file->f_pos;
@@ -329,7 +303,6 @@ loff_t seq_lseek(struct file *file, loff
/* with extreme prejudice... */
file->f_pos = 0;
m->read_pos = 0;
- m->version = 0;
m->index = 0;
m->count = 0;
} else {
@@ -340,7 +313,6 @@ loff_t seq_lseek(struct file *file, loff
file->f_pos = offset;
}
}
- file->f_version = m->version;
mutex_unlock(&m->lock);
return retval;
}
--- a/include/linux/seq_file.h~seq_file-remove-m-version
+++ a/include/linux/seq_file.h
@@ -21,7 +21,6 @@ struct seq_file {
size_t pad_until;
loff_t index;
loff_t read_pos;
- u64 version;
struct mutex lock;
const struct seq_operations *op;
int poll_event;
_