[PATCH 0/4] dm-netlink: Add netlink events to dm

[PATCH 0/4] dm-netlink: Add netlink events to dm

[Mike Anderson]

This patch series adds netlink event support to dm

A early patch series was posted in this thread.
http://article.gmane.org/gmane.linux.kernel.device-mapper.devel/1409

The patches have been broken down into smaller chunks compared to the
previous series to allow for easier review and also updated to newer
kernel interfaces.

This patch series contains the following:
1. Add dm-netlink skeleton (dm-netlink.patch)
2. Add support for the event functions (dm-netlink-add-netlink.patch)
3. Add event calls for failed and reinstated paths (dm-netlink-mpath.patch)
4. Add mempool support to dm-netlink (dm-netlink-mempool.patch)

-andmike
--
Michael Anderson
andmike@us.ibm.com

[PATCH 1/4] dm-netlink: Add dm-netlink skeleton

[Mike Anderson]

From: Mike Anderson <andmike@us.ibm.com>

This patch adds a dm-netlink skeleton support to the Makefile, and the dm
directory.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
---

 drivers/md/Kconfig      |    5 ++
 drivers/md/Makefile     |    4 ++
 drivers/md/dm-netlink.c |   96 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/md/dm-netlink.h |   42 +++++++++++++++++++++
 drivers/md/dm.c         |    2 +
 drivers/md/dm.h         |    1 
 include/linux/netlink.h |    2 -
 7 files changed, 151 insertions(+), 1 deletion(-)

Index: linux-2.6-patched/drivers/md/dm-netlink.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-patched/drivers/md/dm-netlink.c	2007-01-09 01:11:57.000000000 -0800
@@ -0,0 +1,96 @@
+/*
+ * Device Mapper Netlink Support (dm-netlink)
+ *
+ * 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.
+ *
+ * Copyright IBM Corporation, 2005, 2006
+ * 	Author: Mike Anderson <andmike@us.ibm.com>
+ */
+#include <linux/module.h>
+#include <linux/mempool.h>
+#include <linux/time.h>
+#include <linux/jiffies.h>
+#include <linux/security.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include "dm.h"
+
+#define EVENT_SKB_SIZE	NLMSG_GOODSIZE
+
+struct dm_event_cache {
+	struct kmem_cache *cache;
+	unsigned skb_size;
+};
+
+static struct dm_event_cache dme_cache;
+
+static int dme_cache_init(struct dm_event_cache *dc, unsigned skb_size)
+{
+	dc->skb_size = skb_size;
+
+	dc->cache = kmem_cache_create("dm_events",
+			   sizeof(struct dm_event), 0, 0, NULL, NULL);
+
+	if (!dc->cache)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void dme_cache_destroy(struct dm_event_cache *dc)
+{
+	kmem_cache_destroy(dc->cache);
+}
+
+static void dme_cache_event_put(struct dm_event *evt)
+{
+	struct dm_event_cache *dc = evt->cdata;
+	kmem_cache_free(dc->cache, evt);
+}
+
+static struct dm_event* dme_cache_event_get(struct dm_event_cache *dc)
+{
+	struct dm_event *evt;
+
+	evt = kmem_cache_alloc(dc->cache, GFP_ATOMIC);
+	if (evt) {
+		evt->cdata = dc;
+		evt->skb = alloc_skb(dc->skb_size, GFP_ATOMIC);
+		if (!evt->skb)
+			goto cache_out;
+	}
+
+	return evt;
+
+cache_out:
+	dme_cache_event_put(evt);
+	return NULL;
+}
+
+int __init dm_netlink_init(void)
+{
+	int err;
+
+	err = dme_cache_init(&dme_cache, EVENT_SKB_SIZE);
+	if (!err)
+		printk(KERN_DEBUG "dm-netlink version 0.0.6 loaded\n");
+
+	return err;
+}
+
+void dm_netlink_exit(void)
+{
+	dme_cache_destroy(&dme_cache);
+}
Index: linux-2.6-patched/include/linux/netlink.h
===================================================================
--- linux-2.6-patched.orig/include/linux/netlink.h	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/include/linux/netlink.h	2007-01-09 01:11:57.000000000 -0800
@@ -21,7 +21,7 @@
 #define NETLINK_DNRTMSG		14	/* DECnet routing messages */
 #define NETLINK_KOBJECT_UEVENT	15	/* Kernel messages to userspace */
 #define NETLINK_GENERIC		16
-/* leave room for NETLINK_DM (DM Events) */
+#define NETLINK_DM		17	/* Device Mapper */
 #define NETLINK_SCSITRANSPORT	18	/* SCSI Transports */
 
 #define MAX_LINKS 32		
Index: linux-2.6-patched/drivers/md/Makefile
===================================================================
--- linux-2.6-patched.orig/drivers/md/Makefile	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/drivers/md/Makefile	2007-01-09 01:11:57.000000000 -0800
@@ -45,6 +45,10 @@
 altivec_flags := -maltivec -mabi=altivec
 endif
 
+ifeq ($(CONFIG_DM_NETLINK_EVENT),y)
+dm-mod-objs			+= dm-netlink.o
+endif
+
 targets += raid6int1.c
 $(obj)/raid6int1.c:   UNROLL := 1
 $(obj)/raid6int1.c:   $(src)/raid6int.uc $(src)/unroll.pl FORCE
Index: linux-2.6-patched/drivers/md/Kconfig
===================================================================
--- linux-2.6-patched.orig/drivers/md/Kconfig	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/drivers/md/Kconfig	2007-01-09 01:11:57.000000000 -0800
@@ -262,6 +262,11 @@
 	---help---
 	  Multipath support for EMC CX/AX series hardware.
 
+config DM_NETLINK_EVENT
+	bool "DM netlink events (EXPERIMENTAL)"
+	depends on BLK_DEV_DM && EXPERIMENTAL
+	---help---
+	Generate netlink events for DM events.
 endmenu
 
 endif
Index: linux-2.6-patched/drivers/md/dm-netlink.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-patched/drivers/md/dm-netlink.h	2007-01-09 01:11:57.000000000 -0800
@@ -0,0 +1,42 @@
+/*
+ * Device Mapper Netlink Support
+ *
+ * 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.
+ *
+ * Copyright IBM Corporation, 2005, 2006
+ * 	Author: Mike Anderson <andmike@us.ibm.com>
+ */
+#ifndef DM_NETLINK_H
+#define DM_NETLINK_H
+
+struct dm_event {
+	void *cdata;
+	struct sk_buff *skb;
+	struct list_head elist;
+};
+
+#ifdef CONFIG_DM_NETLINK_EVENT
+int dm_netlink_init(void);
+void dm_netlink_exit(void);
+#else
+static inline int __init dm_netlink_init(void)
+{
+	return 0;
+}
+static inline void dm_netlink_exit(void)
+{ }
+#endif
+
+#endif /* DM_NETLINK_H */
Index: linux-2.6-patched/drivers/md/dm.c
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm.c	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm.c	2007-01-09 01:11:57.000000000 -0800
@@ -178,6 +178,7 @@
 	dm_linear_init,
 	dm_stripe_init,
 	dm_interface_init,
+	dm_netlink_init,
 };
 
 void (*_exits[])(void) = {
@@ -186,6 +187,7 @@
 	dm_linear_exit,
 	dm_stripe_exit,
 	dm_interface_exit,
+	dm_netlink_exit,
 };
 
 static int __init dm_init(void)
Index: linux-2.6-patched/drivers/md/dm.h
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm.h	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm.h	2007-01-09 01:11:57.000000000 -0800
@@ -15,6 +15,7 @@
 #include <linux/list.h>
 #include <linux/blkdev.h>
 #include <linux/hdreg.h>
+#include "dm-netlink.h"
 
 #define DM_NAME "device-mapper"
 

[PATCH 2/4] dm-netlink: Add support for the event functions

[Mike Anderson]

From: Mike Anderson <andmike@us.ibm.com>

This patch adds support for the dm_path_event dm_send_event functions which
create and send netlink attribute events.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
---

 drivers/md/dm-netlink.c    |  204 ++++++++++++++++++++++++++++++++++++++++++++-
 drivers/md/dm-netlink.h    |    9 +
 drivers/md/dm.c            |   26 +++++
 drivers/md/dm.h            |    2 
 include/linux/dm-netlink.h |   50 +++++++++++
 5 files changed, 289 insertions(+), 2 deletions(-)

Index: linux-2.6-patched/drivers/md/dm-netlink.c
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm-netlink.c	2007-01-09 01:11:57.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm-netlink.c	2007-01-09 01:12:02.000000000 -0800
@@ -79,13 +79,213 @@
 	return NULL;
 }
 
+static struct sock *dm_netlink_sock;
+static u32 dm_netlink_daemon_pid;
+static DEFINE_SPINLOCK(pid_lock);
+
+static u64 dm_event_seqnum;
+static DEFINE_SPINLOCK(sequence_lock);
+
+static struct dm_event *dm_netlink_build_path_msg(char* dm_name, int type, int
+					   nr_valid_paths)
+{
+	struct dm_event *evt;
+	struct nlmsghdr	*nlh;
+	struct dm_netlink_msghdr *dm_nlh;
+	u64 seq;
+	struct timeval tv;
+	int err = -ENOBUFS;
+
+	evt = dme_cache_event_get(&dme_cache);
+	if (!evt) {
+		printk(KERN_ERR "%s: dme_cache_event_get %d\n",
+		       __FUNCTION__, err);
+		err = -ENOMEM;
+		goto out;
+	}
+
+	nlh = nlmsg_put(evt->skb, 0, 0, DM_EVENT,
+			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_event_seqnum;
+	spin_unlock(&sequence_lock);
+	do_gettimeofday(&tv);
+
+	NLA_PUT_U64(evt->skb, DM_E_ATTR_SEQNUM, seq);
+	NLA_PUT_U64(evt->skb, DM_E_ATTR_TSSEC, tv.tv_sec);
+	NLA_PUT_U64(evt->skb, DM_E_ATTR_TSUSEC, tv.tv_usec);
+	NLA_PUT_STRING(evt->skb, DM_E_ATTR_DMNAME, dm_name);
+	NLA_PUT_U32(evt->skb, DM_E_ATTR_VLDPTHS, nr_valid_paths);
+
+	return evt;
+
+nla_put_failure:
+	printk(KERN_ERR "%s: nla_put_failure\n", __FUNCTION__);
+	nlmsg_free(evt->skb);
+	dme_cache_event_put(evt);
+out:
+	return ERR_PTR(err);
+
+}
+
+/**
+ * dm_send_event - called to send a completed event message
+ *
+ * @md_name:	string containing md device name
+ * @evt:	pointer of event to send
+ *
+ **/
+void dm_send_event(char *md_name, struct dm_event *evt)
+{
+	struct nlmsghdr *nlh = (struct nlmsghdr *) evt->skb->data;
+	int err;
+
+	NLA_PUT_STRING(evt->skb, DM_E_ATTR_MDNAME, md_name);
+	nlmsg_end(evt->skb, nlh);
+
+	spin_lock(&pid_lock);
+	nlh->nlmsg_pid = dm_netlink_daemon_pid;
+	spin_unlock(&pid_lock);
+
+	if (!nlh->nlmsg_pid)
+		goto no_pid;
+
+	err = nlmsg_unicast(dm_netlink_sock, evt->skb, nlh->nlmsg_pid);
+
+	if (err && (err != -ESRCH))
+		printk(KERN_ERR "%s: nlmsg_unicast failed %d\n",
+		       __FUNCTION__, err);
+	goto out;
+
+nla_put_failure:
+	printk(KERN_ERR "%s: nla_put_failure\n", __FUNCTION__);
+no_pid:
+	nlmsg_free(evt->skb);
+out:
+	dme_cache_event_put(evt);
+	return;
+}
+EXPORT_SYMBOL(dm_send_event);
+
+/**
+ * dm_path_event - called to create a new path event and queue it
+ *
+ * @evt_type:		enum of path event type
+ * @t:			pointer to a dm_table
+ * @dm_name:		dm name string
+ * @nr_valid_paths:	number of valid paths remaining
+ *
+ **/
+void dm_path_event(enum dm_event_type evt_type, struct dm_table *t,
+			char* dm_name, int nr_valid_paths)
+{
+	struct dm_event *evt;
+	evt = dm_netlink_build_path_msg(dm_name, evt_type, nr_valid_paths);
+
+	if (evt) {
+		struct mapped_device *md = dm_table_get_md(t);
+		dm_add_event(md, evt);
+		dm_put(md);
+	}
+
+	return;
+}
+
+EXPORT_SYMBOL(dm_path_event);
+
+static int dm_netlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
+			       int *errp)
+{
+	int ret = -1;
+
+	if (security_netlink_recv(skb, CAP_SYS_ADMIN)) {
+		*errp = -EPERM;
+		goto out;
+	}
+
+	spin_lock(&pid_lock);
+	if (dm_netlink_daemon_pid) {
+		if (dm_netlink_daemon_pid != nlh->nlmsg_pid) {
+			*errp = -EBUSY;
+			goto out;
+		}
+	} else {
+		dm_netlink_daemon_pid = nlh->nlmsg_pid;
+	}
+	spin_unlock(&pid_lock);
+
+	ret = 0;
+out:
+	return ret;
+
+}
+
+static void dm_netlink_rcv(struct sock *sk, int len)
+{
+	unsigned int qlen;
+
+	do {
+		netlink_run_queue(sk, &qlen, &dm_netlink_rcv_msg);
+	} while (qlen);
+
+}
+
+static int dm_netlink_rcv_event(struct notifier_block *this,
+				unsigned long event, void *ptr)
+{
+	struct netlink_notify *n = ptr;
+
+	spin_lock(&pid_lock);
+	if (event == NETLINK_URELEASE &&
+	    n->protocol == NETLINK_DM && n->pid) {
+		if ( n->pid == dm_netlink_daemon_pid  ) {
+			dm_netlink_daemon_pid = 0;
+		}
+	}
+	spin_unlock(&pid_lock);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block dm_netlink_notifier = {
+	.notifier_call  = dm_netlink_rcv_event,
+};
+
+
 int __init dm_netlink_init(void)
 {
 	int err;
 
+	err = netlink_register_notifier(&dm_netlink_notifier);
+	if (err)
+		return err;
+
+	dm_netlink_sock = netlink_kernel_create(NETLINK_DM, 0,
+					   dm_netlink_rcv, THIS_MODULE);
+	if (!dm_netlink_sock) {
+		err = -ENOBUFS;
+		goto notifier_out;
+	}
 	err = dme_cache_init(&dme_cache, EVENT_SKB_SIZE);
-	if (!err)
-		printk(KERN_DEBUG "dm-netlink version 0.0.6 loaded\n");
+	if (err)
+		goto socket_out;
+
+	printk(KERN_DEBUG "dm-netlink version 0.0.7 loaded\n");
+
+	return err;
+
+socket_out:
+	sock_release(dm_netlink_sock->sk_socket);
+notifier_out:
+	netlink_unregister_notifier(&dm_netlink_notifier);
+	printk(KERN_ERR "%s: failed %d\n", __FUNCTION__, err);
 
 	return err;
 }
Index: linux-2.6-patched/drivers/md/dm-netlink.h
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm-netlink.h	2007-01-09 01:11:57.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm-netlink.h	2007-01-09 01:12:02.000000000 -0800
@@ -21,6 +21,8 @@
 #ifndef DM_NETLINK_H
 #define DM_NETLINK_H
 
+#include <linux/dm-netlink.h>
+
 struct dm_event {
 	void *cdata;
 	struct sk_buff *skb;
@@ -28,9 +30,16 @@
 };
 
 #ifdef CONFIG_DM_NETLINK_EVENT
+void dm_send_event(char *, struct dm_event *);
+void dm_path_event(enum dm_event_type, struct dm_table *, char *, int);
 int dm_netlink_init(void);
 void dm_netlink_exit(void);
 #else
+static inline void dm_send_event(char *, struct dm_event *)
+{ }
+static inline void dm_path_event(enum dm_event_type, struct dm_table *, char *,
+				 int)
+{ }
 static inline int __init dm_netlink_init(void)
 {
 	return 0;
Index: linux-2.6-patched/include/linux/dm-netlink.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-patched/include/linux/dm-netlink.h	2007-01-09 01:12:02.000000000 -0800
@@ -0,0 +1,50 @@
+/*
+ * Device Mapper Netlink Support
+ *
+ * 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.
+ *
+ * Copyright IBM Corporation, 2005, 2006
+ * 	Author: Mike Anderson <andmike@us.ibm.com>
+ */
+#ifndef LINUX_DM_NETLINK_H
+#define LINUX_DM_NETLINK_H
+
+#define DM_EVENT NLMSG_MIN_TYPE + 0x1
+
+enum dm_event_type {
+	DM_EVENT_FAIL_PATH = 1,
+	DM_EVENT_REINSTATE_PATH = 2,
+	DM_EVENT_MAX,
+};
+
+enum dm_event_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_VLDPTHS	= 6,
+	DM_E_ATTR_MDNAME	= 7,
+	DM_E_ATTR_MAX,
+};
+
+struct dm_netlink_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-patched/drivers/md/dm.c
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm.c	2007-01-09 01:11:57.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm.c	2007-01-09 01:12:02.000000000 -0800
@@ -112,6 +112,8 @@
 	 */
 	atomic_t event_nr;
 	wait_queue_head_t eventq;
+	struct list_head event_list;
+	spinlock_t event_lock;
 
 	/*
 	 * freeze/thaw support require holding onto a super block
@@ -993,6 +995,8 @@
 	atomic_set(&md->holders, 1);
 	atomic_set(&md->open_count, 0);
 	atomic_set(&md->event_nr, 0);
+	INIT_LIST_HEAD(&md->event_list);
+	spin_lock_init(&md->event_lock);
 
 	md->queue = blk_alloc_queue(GFP_KERNEL);
 	if (!md->queue)
@@ -1091,6 +1095,18 @@
 static void event_callback(void *context)
 {
 	struct mapped_device *md = (struct mapped_device *) context;
+	unsigned long flags;
+	struct dm_event *evt, *next;
+	LIST_HEAD(events);
+
+	spin_lock_irqsave(&md->event_lock, flags);
+	list_splice_init(&md->event_list, &events);
+	spin_unlock_irqrestore(&md->event_lock, flags);
+
+	list_for_each_entry_safe(evt, next, &events, elist) {
+		list_del_init(&evt->elist);
+		dm_send_event(md->name, evt);
+	}
 
 	atomic_inc(&md->event_nr);
 	wake_up(&md->eventq);
@@ -1507,6 +1523,16 @@
 			(event_nr != atomic_read(&md->event_nr)));
 }
 
+void dm_add_event(struct mapped_device *md, struct dm_event *evt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&md->event_lock, flags);
+	list_add(&evt->elist, &md->event_list);
+	spin_unlock_irqrestore(&md->event_lock, flags);
+
+}
+
 /*
  * The gendisk is only valid as long as you have a reference
  * count on 'md'.
Index: linux-2.6-patched/drivers/md/dm.h
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm.h	2007-01-09 01:11:57.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm.h	2007-01-09 01:12:02.000000000 -0800
@@ -152,4 +152,6 @@
 int dm_open_count(struct mapped_device *md);
 int dm_lock_for_deletion(struct mapped_device *md);
 
+void dm_add_event(struct mapped_device *md, struct dm_event *evt);
+
 #endif

[PATCH 3/4] dm-netlink: Add calls for failed and reinstated paths

[Mike Anderson]

From: Mike Anderson <andmike@us.ibm.com>

This patch adds calls to dm_path_event for a failed path and a reinstated
path.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
---

 drivers/md/dm-mpath.c |    6 ++++++
 1 file changed, 6 insertions(+)

Index: linux-2.6-patched/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm-mpath.c	2007-01-09 01:11:44.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm-mpath.c	2007-01-09 01:12:05.000000000 -0800
@@ -834,6 +834,9 @@
 	if (pgpath == m->current_pgpath)
 		m->current_pgpath = NULL;
 
+	dm_path_event(DM_EVENT_FAIL_PATH, m->ti->table,
+			 pgpath->path.dev->name, m->nr_valid_paths);
+
 	queue_work(kmultipathd, &m->trigger_event);
 
 out:
@@ -873,6 +876,9 @@
 	if (!m->nr_valid_paths++ && m->queue_size)
 		queue_work(kmultipathd, &m->process_queued_ios);
 
+	dm_path_event(DM_EVENT_REINSTATE_PATH, m->ti->table,
+			      pgpath->path.dev->name, m->nr_valid_paths);
+
 	queue_work(kmultipathd, &m->trigger_event);
 
 out:

[PATCH 4/4] dm-netlink: Add mempool support to dm-netlink

[Mike Anderson]

From: Mike Anderson <andmike@us.ibm.com>

This patch adds mempool support to dm-netlink.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
---
The mempool support was originally derived from:
drivers/scsi/scsi_transport_iscsi.c.

 drivers/md/dm-netlink.c |  152 ++++++++++++++++++++++++++++++++++++++++++------
 drivers/md/dm-netlink.h |    1 
 2 files changed, 134 insertions(+), 19 deletions(-)

Index: linux-2.6-patched/drivers/md/dm-netlink.c
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm-netlink.c	2007-01-09 01:12:02.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm-netlink.c	2007-01-09 01:12:12.000000000 -0800
@@ -17,6 +17,8 @@
  *
  * Copyright IBM Corporation, 2005, 2006
  * 	Author: Mike Anderson <andmike@us.ibm.com>
+ *
+ * skb mempool derived from drivers/scsi/scsi_transport_iscsi.c
  */
 #include <linux/module.h>
 #include <linux/mempool.h>
@@ -27,56 +29,164 @@
 #include <net/netlink.h>
 #include "dm.h"
 
-#define EVENT_SKB_SIZE	NLMSG_GOODSIZE
+#define EVENT_SKB_SIZE		NLMSG_SPACE(128)
+#define MIN_EVENT_SKBS		16
+#define HIWAT_EVENT_SKBS	32
 
 struct dm_event_cache {
 	struct kmem_cache *cache;
 	unsigned skb_size;
+	unsigned hiwat;
+	mempool_t *pool;
+	spinlock_t used_list_lock;
+	struct list_head used_list;
 };
 
 static struct dm_event_cache dme_cache;
 
-static int dme_cache_init(struct dm_event_cache *dc, unsigned skb_size)
+static void* mp_alloc_dm_event(gfp_t gfp_mask, void *pool_data)
+{
+	struct dm_event *evt;
+	struct dm_event_cache *dc = pool_data;
+
+	evt = kmem_cache_alloc(dc->cache, gfp_mask);
+	if (!evt)
+		goto out;
+
+	evt->skb = alloc_skb(dc->skb_size, gfp_mask);
+	if (!evt->skb)
+		goto cache_out;
+	return evt;
+
+cache_out:
+	kmem_cache_free(dc->cache, evt);
+out:
+	return NULL;
+}
+
+static void mp_free_dm_event(void *element, void *pool_data)
+{
+	struct dm_event *evt = element;
+	struct dm_event_cache *dc = pool_data;
+
+	kfree_skb(evt->skb);
+	kmem_cache_free(dc->cache, evt);
+}
+
+static int dme_cache_init(struct dm_event_cache *dc, unsigned skb_size,
+			unsigned min_nr, unsigned hiwat)
 {
 	dc->skb_size = skb_size;
+	dc->hiwat = hiwat;
+	spin_lock_init(&dc->used_list_lock);
+	INIT_LIST_HEAD(&dc->used_list);
 
 	dc->cache = kmem_cache_create("dm_events",
 			   sizeof(struct dm_event), 0, 0, NULL, NULL);
 
 	if (!dc->cache)
-		return -ENOMEM;
+		goto cache_err_out;
+
+	dc->pool = mempool_create(min_nr, mp_alloc_dm_event,
+				   mp_free_dm_event, dc);
+	if (!dc->pool)
+		goto mempool_err_out;
 
 	return 0;
+
+mempool_err_out:
+	kmem_cache_destroy(dc->cache);
+cache_err_out:
+	return -ENOMEM;
 }
 
 static void dme_cache_destroy(struct dm_event_cache *dc)
 {
+	mempool_destroy(dc->pool);
 	kmem_cache_destroy(dc->cache);
 }
 
+static void __dme_cache_event_put(struct dm_event *evt)
+{
+	struct dm_event_cache *dc = evt->cdata;
+	struct sk_buff *skb = evt->skb;
+
+	if (!skb_shared(skb)) {
+		list_del(&evt->used_list);
+		skb_orphan(skb);
+
+		/* Init in case sent to pool */
+		skb->len = 0;
+		skb->tail = skb->head;
+
+		mempool_free(evt, dc->pool);
+	}
+}
+
 static void dme_cache_event_put(struct dm_event *evt)
 {
 	struct dm_event_cache *dc = evt->cdata;
-	kmem_cache_free(dc->cache, evt);
+	unsigned long flags;
+
+	spin_lock_irqsave(&dc->used_list_lock, flags);
+	__dme_cache_event_put(evt);
+	spin_unlock_irqrestore(&dc->used_list_lock, flags);
+}
+
+static void mp_cleanup_evt_pid(int pid, struct dm_event *evt)
+{
+	struct sk_buff *skb = evt->skb;
+	struct nlmsghdr *nlh;
+
+	if (skb->sk) {
+		nlh = (struct nlmsghdr *)skb->data;
+		if (nlh->nlmsg_pid == pid) {
+			if (skb->next && skb->sk)
+				skb_unlink(skb, &skb->sk->sk_receive_queue);
+			atomic_set(&skb->users, 1);
+			__dme_cache_event_put(evt);
+		}
+	}
+}
+
+static void mp_complete(struct dm_event_cache *dc, int release_pid)
+{
+	unsigned long flags;
+	struct dm_event *evt, *n;
+
+	spin_lock_irqsave(&dc->used_list_lock, flags);
+	if (!list_empty(&dc->used_list)) {
+		list_for_each_entry_safe(evt, n, &dc->used_list, used_list) {
+			if (release_pid) {
+				mp_cleanup_evt_pid(release_pid, evt);
+			} else {
+				__dme_cache_event_put(evt);
+			}
+		}
+	}
+	spin_unlock_irqrestore(&dc->used_list_lock, flags);
 }
 
 static struct dm_event* dme_cache_event_get(struct dm_event_cache *dc)
 {
+	unsigned long flags;
 	struct dm_event *evt;
 
-	evt = kmem_cache_alloc(dc->cache, GFP_ATOMIC);
-	if (evt) {
-		evt->cdata = dc;
-		evt->skb = alloc_skb(dc->skb_size, GFP_ATOMIC);
-		if (!evt->skb)
-			goto cache_out;
-	}
+	/* Check for ones we can complete before we alloc */
+	mp_complete(dc, 0);
 
-	return evt;
+	evt = mempool_alloc(dc->pool, GFP_ATOMIC);
+	if (!evt)
+		return NULL;
+
+	evt->cdata = dc;
+	skb_get(evt->skb);
+	INIT_LIST_HEAD(&evt->used_list);
+	spin_lock_irqsave(&dc->used_list_lock, flags);
+	list_add(&evt->used_list, &dc->used_list);
+	spin_unlock_irqrestore(&dc->used_list_lock, flags);
 
-cache_out:
-	dme_cache_event_put(evt);
-	return NULL;
+	return evt;
 }
 
 static struct sock *dm_netlink_sock;
@@ -128,7 +238,8 @@
 
 nla_put_failure:
 	printk(KERN_ERR "%s: nla_put_failure\n", __FUNCTION__);
-	nlmsg_free(evt->skb);
+	/* Set skb users so mp_complete can free */
+	atomic_set(&evt->skb->users, 1);
 	dme_cache_event_put(evt);
 out:
 	return ERR_PTR(err);
@@ -167,9 +278,10 @@
 nla_put_failure:
 	printk(KERN_ERR "%s: nla_put_failure\n", __FUNCTION__);
 no_pid:
-	nlmsg_free(evt->skb);
-out:
+	/* Set skb users so mp_complete can free */
+	atomic_set(&evt->skb->users, 1);
 	dme_cache_event_put(evt);
+out:
 	return;
 }
 EXPORT_SYMBOL(dm_send_event);
@@ -246,6 +358,7 @@
 	if (event == NETLINK_URELEASE &&
 	    n->protocol == NETLINK_DM && n->pid) {
 		if ( n->pid == dm_netlink_daemon_pid  ) {
+			mp_complete(&dme_cache, dm_netlink_daemon_pid);
 			dm_netlink_daemon_pid = 0;
 		}
 	}
@@ -273,7 +386,8 @@
 		err = -ENOBUFS;
 		goto notifier_out;
 	}
-	err = dme_cache_init(&dme_cache, EVENT_SKB_SIZE);
+	err = dme_cache_init(&dme_cache, EVENT_SKB_SIZE, MIN_EVENT_SKBS,
+				HIWAT_EVENT_SKBS);
 	if (err)
 		goto socket_out;
 
Index: linux-2.6-patched/drivers/md/dm-netlink.h
===================================================================
--- linux-2.6-patched.orig/drivers/md/dm-netlink.h	2007-01-09 01:12:02.000000000 -0800
+++ linux-2.6-patched/drivers/md/dm-netlink.h	2007-01-09 01:12:12.000000000 -0800
@@ -27,6 +27,7 @@
 	void *cdata;
 	struct sk_buff *skb;
 	struct list_head elist;
+	struct list_head used_list;
 };
 
 #ifdef CONFIG_DM_NETLINK_EVENT