[PATCH 09/39] ipv6/flowlabel: simplify pid namespace lookup

Christoph Hellwig
2018-04-19T12:41:10Z

The shole seq_file sequence already operates under a single RCU lock pair,
so move the pid namespace lookup into it, and stop grabbing a reference
and remove all kinds of boilerplate code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
net/ipv6/ip6_flowlabel.c | 28 +++++-----------------------
1 file changed, 5 insertions(+), 23 deletions(-)

diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index c05c4e82a7ca..a9f221d45ef9 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -754,7 +754,10 @@ static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
+ struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
+
rcu_read_lock_bh();
+ state->pid_ns = task_active_pid_ns(current);
return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

@@ -810,36 +813,15 @@ static const struct seq_operations ip6fl_seq_ops = {

static int ip6fl_seq_open(struct inode *inode, struct file *file)
{
- struct seq_file *seq;
- struct ip6fl_iter_state *state;
- int err;
-
- err = seq_open_net(inode, file, &ip6fl_seq_ops,
+ return seq_open_net(inode, file, &ip6fl_seq_ops,
sizeof(struct ip6fl_iter_state));
-
- if (!err) {
- seq = file->private_data;
- state = ip6fl_seq_private(seq);
- rcu_read_lock();
- state->pid_ns = get_pid_ns(task_active_pid_ns(current));
- rcu_read_unlock();
- }
- return err;
-}
-
-static int ip6fl_seq_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = file->private_data;
- struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
- put_pid_ns(state->pid_ns);
- return seq_release_net(inode, file);
}

static const struct file_operations ip6fl_seq_fops = {
.open = ip6fl_seq_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = ip6fl_seq_release,
+ .release = seq_release_net,
};

static int __net_init ip6_flowlabel_proc_init(struct net *net)
--
2.17.0

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