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.

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>
Link: http://lkml.kernel.org/r/20200317193201.9924-4-adobriyan@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 1600034..79781eb 100644 (file)
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -68,13 +68,6 @@ 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 +87,6 @@ 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 +153,11 @@ 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 +168,6 @@ 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 +220,6 @@ 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);
@@ -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_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;
@@ -329,7 +303,6 @@ 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 +313,6 @@ 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;
 }

diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 770c2bf..1672cf6 100644 (file)
--- a/include/linux/seq_file.h
+++ b/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;