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Commit f1514638 authored by Kay Sievers's avatar Kay Sievers Committed by Al Viro
Browse files

fs: seq_file - add event counter to simplify poll() support 



Moving the event counter into the dynamically allocated 'struc seq_file'
allows poll() support without the need to allocate its own tracking
structure.

All current users are switched over to use the new counter.

Requested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarNeilBrown <neilb@suse.de>
Tested-by: default avatarLucas De Marchi <lucas.demarchi@profusion.mobi>
Signed-off-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 72c5052d

drivers/md/md.c

+8 −18
Original line number Diff line number Diff line
@@ -6394,16 +6394,11 @@ static void md_seq_stop(struct seq_file *seq, void *v) 
		mddev_put(mddev);

}



struct mdstat_info {

	int event;

};



static int md_seq_show(struct seq_file *seq, void *v)

{

	mddev_t *mddev = v;

	sector_t sectors;

	mdk_rdev_t *rdev;

	struct mdstat_info *mi = seq->private;

	struct bitmap *bitmap;



	if (v == (void*)1) {
@@ -6415,7 +6410,7 @@ static int md_seq_show(struct seq_file *seq, void *v) 


		spin_unlock(&pers_lock);

		seq_printf(seq, "\n");

		mi->event = atomic_read(&md_event_count);

		seq->poll_event = atomic_read(&md_event_count);

		return 0;

	}

	if (v == (void*)2) {
@@ -6527,26 +6522,21 @@ static const struct seq_operations md_seq_ops = { 


static int md_seq_open(struct inode *inode, struct file *file)

{

	struct seq_file *seq;

	int error;

	struct mdstat_info *mi = kmalloc(sizeof(*mi), GFP_KERNEL);

	if (mi == NULL)

		return -ENOMEM;



	error = seq_open(file, &md_seq_ops);

	if (error)

		kfree(mi);

	else {

		struct seq_file *p = file->private_data;

		p->private = mi;

		mi->event = atomic_read(&md_event_count);

	}

		return error;



	seq = file->private_data;

	seq->poll_event = atomic_read(&md_event_count);

	return error;

}



static unsigned int mdstat_poll(struct file *filp, poll_table *wait)

{

	struct seq_file *m = filp->private_data;

	struct mdstat_info *mi = m->private;

	struct seq_file *seq = filp->private_data;

	int mask;



	poll_wait(filp, &md_event_waiters, wait);
@@ -6554,7 +6544,7 @@ static unsigned int mdstat_poll(struct file *filp, poll_table *wait) 
	/* always allow read */

	mask = POLLIN | POLLRDNORM;



	if (mi->event != atomic_read(&md_event_count))

	if (seq->poll_event != atomic_read(&md_event_count))

		mask |= POLLERR | POLLPRI;

	return mask;

}

fs/namespace.c

+2 −2
Original line number Diff line number Diff line
@@ -934,8 +934,8 @@ int mnt_had_events(struct proc_mounts *p) 
	int res = 0;



	br_read_lock(vfsmount_lock);

	if (p->event != ns->event) {

		p->event = ns->event;

	if (p->m.poll_event != ns->event) {

		p->m.poll_event = ns->event;

		res = 1;

	}

	br_read_unlock(vfsmount_lock);

fs/proc/base.c

+1 −1
Original line number Diff line number Diff line
@@ -673,7 +673,7 @@ static int mounts_open_common(struct inode *inode, struct file *file, 
	p->m.private = p;

	p->ns = ns;

	p->root = root;

	p->event = ns->event;

	p->m.poll_event = ns->event;



	return 0;

include/linux/mnt_namespace.h

+0 −1
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ struct proc_mounts { 
	struct seq_file m; /* must be the first element */

	struct mnt_namespace *ns;

	struct path root;

	int event;

};



struct fs_struct;

include/linux/seq_file.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ struct seq_file { 
	u64 version;

	struct mutex lock;

	const struct seq_operations *op;

	int poll_event;

	void *private;

};