[dm-devel] Re: [PATCH RFC 2/4] dm-netlink netlink support
Mike Anderson
andmike at us.ibm.com
Wed Nov 30 08:26:25 UTC 2005
This patch adds netlink support to dm-netlink. It also adds support for
using netlink attributes for the event messages.
Signed-off-by: Mike Anderson <andmike at us.ibm.com>
drivers/md/dm-netlink.c | 188 ++++++++++++++++++++++++++++++++++++++++++++-
drivers/md/dm-netlink.h | 40 +++++++++
include/linux/dm-netlink.h | 46 +++++++++++
3 files changed, 272 insertions(+), 2 deletions(-)
Index: linux-2.6.15-rc1-patched/drivers/md/dm-netlink.c
===================================================================
--- linux-2.6.15-rc1-patched.orig/drivers/md/dm-netlink.c 2005-11-29 23:13:59.000000000 -0800
+++ linux-2.6.15-rc1-patched/drivers/md/dm-netlink.c 2005-11-29 23:28:06.000000000 -0800
@@ -27,6 +27,7 @@
#include <linux/security.h>
#include <net/sock.h>
#include <net/netlink.h>
+#include <linux/dm-netlink.h>
#define MIN_EVT_SKBS 16
#define HIWAT_EVT_SKBS 32
@@ -125,20 +126,203 @@ static struct sk_buff* mempool_zone_get_
return skb;
}
+static struct sock *dm_nl_sock;
+static int dm_nl_daemon_pid;
+
+static u64 dm_evt_seqnum;
+static DEFINE_SPINLOCK(sequence_lock);
+
+static struct sk_buff *dm_nl_build_path_msg(char* dm_name, int type,
+ int blk_err)
+{
+ struct sk_buff *skb;
+ struct nlmsghdr *nlh;
+ struct dm_nl_msghdr *dm_nlh;
+ u64 seq;
+ struct timeval tv;
+ int err = -ENOBUFS;
+
+ skb = mempool_zone_get_skb(&z_dm_evt);
+ if (!skb) {
+ printk(KERN_ERR "%s: mempool_zone_get_skb %d\n",
+ __FUNCTION__, err);
+ err = -ENOMEM;
+ goto out;
+ }
+
+ nlh = nlmsg_put(skb, dm_nl_daemon_pid, 0, DM_EVT,
+ NLMSG_ALIGN(sizeof(*dm_nlh)), 0);
+ if (!nlh)
+ goto nla_put_failure;
+
+ dm_nlh = nlmsg_data(nlh);
+ dm_nlh->type = type;
+ dm_nlh->version = DM_E_ATTR_MAX;
+
+ spin_lock(&sequence_lock);
+ seq = ++dm_evt_seqnum;
+ spin_unlock(&sequence_lock);
+ do_gettimeofday(&tv);
+
+ NLA_PUT_U64(skb, DM_E_ATTR_SEQNUM, seq);
+ NLA_PUT_U64(skb, DM_E_ATTR_TSSEC, tv.tv_sec);
+ NLA_PUT_U64(skb, DM_E_ATTR_TSUSEC, tv.tv_usec);
+ NLA_PUT_STRING(skb, DM_E_ATTR_DMNAME, dm_name);
+
+ if (blk_err)
+ NLA_PUT_U32(skb, DM_E_ATTR_BLKERR, blk_err);
+
+ nlmsg_end(skb, nlh);
+
+ return skb;
+
+nla_put_failure:
+ printk(KERN_ERR "%s: nla_put_failure\n",
+ __FUNCTION__);
+ /* reduce skb users so zone_complete can free */
+ kfree_skb(skb);
+ mempool_zone_complete(&z_dm_evt, 0);
+out:
+ return ERR_PTR(err);
+
+}
+
+static inline void dm_nl_unicast(struct sk_buff *skb)
+{
+ int err;
+
+ if (!dm_nl_sock || !dm_nl_daemon_pid)
+ return;
+
+ err = nlmsg_unicast(dm_nl_sock, skb, dm_nl_daemon_pid);
+ if (err < 0)
+ printk(KERN_ERR "%s: nlmsg_unicast %d\n", __FUNCTION__,
+ err);
+}
+
+void dm_nl_path_fail(char* dm_name, int blk_err)
+{
+ struct sk_buff *msg;
+ msg = dm_nl_build_path_msg(dm_name, DM_EVT_FAIL_PATH, blk_err);
+
+ if (!IS_ERR(msg))
+ dm_nl_unicast(msg);
+}
+
+EXPORT_SYMBOL(dm_nl_path_fail);
+
+void dm_nl_path_reinstate(char* dm_name)
+{
+ struct sk_buff *msg;
+ msg = dm_nl_build_path_msg(dm_name, DM_EVT_REINSTATE_PATH, 0);
+
+ if (!IS_ERR(msg))
+ dm_nl_unicast(msg);
+}
+
+EXPORT_SYMBOL(dm_nl_path_reinstate);
+
+#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
+
+static void dm_nl_rcv_msg(struct sk_buff *skb)
+{
+ int pid, flags;
+ struct nlmsghdr *nlh = (struct nlmsghdr *) skb->data;
+
+ if (skb->len >= NLMSG_SPACE(0)) {
+
+ if (nlh->nlmsg_len < sizeof(*nlh) ||
+ skb->len < nlh->nlmsg_len) {
+ return;
+ }
+ pid = nlh->nlmsg_pid;
+ flags = nlh->nlmsg_flags;
+
+ if (security_netlink_recv(skb))
+ RCV_SKB_FAIL(-EPERM);
+
+ if (dm_nl_daemon_pid) {
+ if (dm_nl_daemon_pid != pid) {
+ RCV_SKB_FAIL(-EBUSY);
+ }
+ } else {
+ dm_nl_daemon_pid = pid;
+ }
+
+ if (flags & NLM_F_ACK)
+ netlink_ack(skb, nlh, 0);
+ }
+}
+
+static void dm_nl_rcv(struct sock *sk, int len)
+{
+ struct sk_buff *skb;
+ unsigned int qlen;
+
+ for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
+ skb = skb_dequeue(&sk->sk_receive_queue);
+ dm_nl_rcv_msg(skb);
+ kfree_skb(skb);
+ }
+}
+
+static int dm_nl_rcv_nl_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+ struct netlink_notify *n = ptr;
+
+ if (event == NETLINK_URELEASE &&
+ n->protocol == NETLINK_DM && n->pid) {
+ if ( n->pid == dm_nl_daemon_pid ) {
+ dm_nl_daemon_pid = 0;
+ }
+ mempool_zone_complete(&z_dm_evt, 1);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block dm_nl_nl_notifier = {
+ .notifier_call = dm_nl_rcv_nl_event,
+};
+
+static struct sock *dm_nl_sock;
+static int dm_nl_daemon_pid;
+
int __init dm_nl_init(void)
{
int err;
+ err = netlink_register_notifier(&dm_nl_nl_notifier);
+ if (err)
+ return err;
+
+ dm_nl_sock = netlink_kernel_create(NETLINK_DM, 0,
+ dm_nl_rcv, THIS_MODULE);
+ if (!dm_nl_sock) {
+ err = -ENOBUFS;
+ goto unregister_notifier;
+ }
+
err = mempool_zone_init(&z_dm_evt, EVT_SKB_SIZE,
MIN_EVT_SKBS, HIWAT_EVT_SKBS);
- if (!err)
- printk(KERN_DEBUG "dm-netlink version 0.0.1 loaded\n");
+ if (err)
+ goto release_socket;
+
+ printk(KERN_DEBUG "dm-netlink version 0.0.1 loaded\n");
return err;
+release_socket:
+ sock_release(dm_nl_sock->sk_socket);
+unregister_notifier:
+ netlink_unregister_notifier(&dm_nl_nl_notifier);
+ printk(KERN_ERR "%s: failed %d\n", __FUNCTION__, err);
+ return err;
}
void dm_nl_exit(void)
{
mempool_destroy(z_dm_evt.pool);
+ sock_release(dm_nl_sock->sk_socket);
+ netlink_unregister_notifier(&dm_nl_nl_notifier);
}
Index: linux-2.6.15-rc1-patched/include/linux/dm-netlink.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15-rc1-patched/include/linux/dm-netlink.h 2005-11-29 23:22:07.000000000 -0800
@@ -0,0 +1,46 @@
+/*
+ * Device Mapper Netlink Support
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Mike Anderson <andmike at us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+#ifndef LINUX_DM_NETLINK_H
+#define LINUX_DM_NETLINK_H
+
+enum dm_evt_attr {
+ DM_E_ATTR_SEQNUM = 1,
+ DM_E_ATTR_TSSEC = 2,
+ DM_E_ATTR_TSUSEC = 3,
+ DM_E_ATTR_DMNAME = 4,
+ DM_E_ATTR_BLKERR = 5,
+ DM_E_ATTR_MAX,
+};
+
+#define DM_EVT NLMSG_MIN_TYPE + 0x1
+
+#define DM_EVT_FAIL_PATH 0x1
+#define DM_EVT_REINSTATE_PATH 0x2
+
+struct dm_nl_msghdr {
+ uint16_t type;
+ uint16_t version;
+ uint16_t reserved1;
+ uint16_t reserved2;
+} __attribute__((aligned(sizeof(uint64_t))));
+
+#endif /* LINUX_DM_NETLINK_H */
Index: linux-2.6.15-rc1-patched/drivers/md/dm-netlink.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15-rc1-patched/drivers/md/dm-netlink.h 2005-11-29 23:22:07.000000000 -0800
@@ -0,0 +1,40 @@
+/*
+ * Device Mapper Netlink Support
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Mike Anderson <andmike at us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ */
+#ifndef DM_NETLINK_H
+#define DM_NETLINK_H
+
+#ifdef CONFIG_DM_NL_SUPPORT
+void dm_nl_path_fail(char*, int);
+void dm_nl_path_reinstate(char*);
+#else
+static inline void dm_nl_path_fail(char* dm_name, int blk_err)
+{
+ return;
+}
+
+static inline void dm_nl_path_reinstate(char* dm_name)
+{
+ return;
+}
+#endif
+
+#endif /* DM_NETLINK_H */
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