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: Andrew Morton akpm@linux-foundation.org
Acked-by: NeilBrown <neilb@suse.de>
Tested-by: Lucas De Marchi lucas.demarchi@profusion.mobi
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 91e31e2..dfc9425 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6394,16 +6394,11 @@
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 @@
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 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 @@
/* 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;
}
diff --git a/fs/namespace.c b/fs/namespace.c
index fe59bd1..cda50fe 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -934,8 +934,8 @@
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);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index be1ff93..3dc5e2a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -673,7 +673,7 @@
p->m.private = p;
p->ns = ns;
p->root = root;
- p->event = ns->event;
+ p->m.poll_event = ns->event;
return 0;
diff --git a/include/linux/mnt_namespace.h b/include/linux/mnt_namespace.h
index 0b89efc..2930485 100644
--- a/include/linux/mnt_namespace.h
+++ b/include/linux/mnt_namespace.h
@@ -18,7 +18,6 @@
struct seq_file m; /* must be the first element */
struct mnt_namespace *ns;
struct path root;
- int event;
};
struct fs_struct;
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 03c0232..be720cd 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -23,6 +23,7 @@
u64 version;
struct mutex lock;
const struct seq_operations *op;
+ int poll_event;
void *private;
};
diff --git a/mm/swapfile.c b/mm/swapfile.c
index ff8dc1a..1b8c339 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1681,19 +1681,14 @@
}
#ifdef CONFIG_PROC_FS
-struct proc_swaps {
- struct seq_file seq;
- int event;
-};
-
static unsigned swaps_poll(struct file *file, poll_table *wait)
{
- struct proc_swaps *s = file->private_data;
+ struct seq_file *seq = file->private_data;
poll_wait(file, &proc_poll_wait, wait);
- if (s->event != atomic_read(&proc_poll_event)) {
- s->event = atomic_read(&proc_poll_event);
+ if (seq->poll_event != atomic_read(&proc_poll_event)) {
+ seq->poll_event = atomic_read(&proc_poll_event);
return POLLIN | POLLRDNORM | POLLERR | POLLPRI;
}
@@ -1783,24 +1778,16 @@
static int swaps_open(struct inode *inode, struct file *file)
{
- struct proc_swaps *s;
+ struct seq_file *seq;
int ret;
- s = kmalloc(sizeof(struct proc_swaps), GFP_KERNEL);
- if (!s)
- return -ENOMEM;
-
- file->private_data = s;
-
ret = seq_open(file, &swaps_op);
- if (ret) {
- kfree(s);
+ if (ret)
return ret;
- }
- s->seq.private = s;
- s->event = atomic_read(&proc_poll_event);
- return ret;
+ seq = file->private_data;
+ seq->poll_event = atomic_read(&proc_poll_event);
+ return 0;
}
static const struct file_operations proc_swaps_operations = {