[RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

Below is a patch to add some hotplug infrastructure to the Linux SCSI
subsystem.

New files:
include/scsi/scsi_hotplug.h
drivers/scsi/scsi_hotplug.c
implements a new exported function:

extern int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
			      unsigned int id, unsigned int lun, enum scsi_topology_action action);

which invokes kobject_hotplug() on a temporary "scsi_topology"
device.  This device represents a target that exists on a topology
(i.e. was just inserted into a hot plug enclosure, or was just created
by a RAID controller management application) but is not yet hooked
into the kernel.

Modified files:
drivers/scsi/Kconfig
drivers/scsi/Makefile
drivers/scsi/megaraid/megaraid_mbox.c
 (will follow in a separate patch)
 is the user of this new function.

In addition, two more infrastructure pieces are necessary:
udev-050-scsi_topology.patch - adds the subsystem name "scsi_topology"
to the list of devices *not* to wait for the creation of files in
sysfs for - scsi_topology devices aren't to be registered in sysfs.

/etc/hotplug/scsi_topology.agent
 handles the hotplug call, and invokes /sys/class/scsi_host/hostX/scan
 and /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.


The flow is as follows:

# echo "2" > /sys/class/scsi_host/host2/logical_drive_created
(to be done by a management application that knows it just created
logical drive #2 on the controller)

megaraid_mbox.c sysfs method converts logical drive number to HCTL
value, calls scsi_topology_hctl_action().

scsi_topology_hctl_action() invokes kobject_hotplug() with a
scsi_topology subsystem device.

kobject_hotplug() calls /sbin/hotplug or /sbin/udevsend (more likely
the latter), which invokes /etc/hotplug/scsi_topology.agent with the
ACTION={add,remove}.

scsi_topology.agent invokes /sys/class/scsi_host/hostX/scan or
 /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.

From this point, we're back into known territory, with the device
being made known, or deleted from, the kernel's view.

Thoughts?

Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

=== drivers/scsi/Kconfig 1.95 vs edited ==--- 1.95/drivers/scsi/Kconfig	2005-01-28 11:14:29 -06:00
+++ edited/drivers/scsi/Kconfig	2005-02-05 13:58:45 -06:00
@@ -185,6 +185,16 @@
 	  there should be no noticeable performance impact as long as you have
 	  logging turned off.
 
+config SCSI_HOTPLUG
+	bool "Hot Plug SCSI devices"
+	depends on SCSI && EXPERIMENTAL
+	default y
+	help
+	  If your driver or management applications know about
+	  device hot plugging (insertion/removal of physical disks in
+	  a topology, or creation/deletion of logical disks on a RAID
+	  controller), say Y here.  Otherwise, say N.
+
 menu "SCSI Transport Attributes"
 	depends on SCSI
 
=== drivers/scsi/Makefile 1.72 vs edited ==--- 1.72/drivers/scsi/Makefile	2004-11-20 14:26:17 -06:00
+++ edited/drivers/scsi/Makefile	2005-02-05 13:58:15 -06:00
@@ -147,6 +147,7 @@
 				   scsi_devinfo.o
 scsi_mod-$(CONFIG_SYSCTL)	+= scsi_sysctl.o
 scsi_mod-$(CONFIG_SCSI_PROC_FS)	+= scsi_proc.o
+scsi_mod-$(CONFIG_SCSI_HOTPLUG)	+= scsi_hotplug.o
 
 sd_mod-objs	:= sd.o
 sr_mod-objs	:= sr.o sr_ioctl.o sr_vendor.o
--- /dev/null	Thu Apr 11 09:25:15 2002
+++ include/scsi/scsi_hotplug.h	Sun Feb  6 23:29:51 2005
@@ -0,0 +1,41 @@
+/*
+ *  SCSI Hotplug
+ *
+ *  Copyright (c) 2005 Dell, Inc <Matt_Domsch@dell.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 _SCSI_SCSI_HOTPLUG_H
+#define _SCSI_SCSI_HOTPLUG_H
+
+#include <linux/config.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_device.h>
+
+enum scsi_topology_action {
+	SCSI_TOPOLOGY_ADDED    = 1,  /* device added in the topology */
+	SCSI_TOPOLOGY_REMOVED  = 2,  /* device removed from the topology */
+};
+
+#if defined (CONFIG_SCSI_HOTPLUG) || defined(CONFIG_SCSI_HOTPLUG_MODULE)
+extern int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
+			      unsigned int id, unsigned int lun, enum scsi_topology_action action);
+#else
+static inline int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
+				    unsigned int id, unsigned int lun, enum scsi_topology_action action)
+{return -ENOSYS;}
+#endif
+
+#endif /* _SCSI_SCSI_HOTPLUG_H */
--- /dev/null	Thu Apr 11 09:25:15 2002
+++ drivers/scsi/scsi_hotplug.c	Sun Feb  6 23:42:21 2005
@@ -0,0 +1,138 @@
+/*
+ *  SCSI Hotplug
+ *
+ *  Copyright (c) 2005 Dell, Inc <Matt_Domsch@dell.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
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <scsi/scsi_hotplug.h>
+
+/*
+ * TODO:
+ * - if CONFIG_SCSI_HOTPLUG=y and CONFIG_SCSI=y, then the exported
+ * functions here get dropped by the vmlinux linker, as there are no
+ * vmlinux users of them (only modules).
+ *
+ */
+
+/* This belongs in include/device.h, as drivers/base/core.c defines it too */
+#define to_dev(obj) container_of(obj, struct device, kobj)
+
+static int scsi_topology_device_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
+			       int num_envp, char *buffer, int buffer_size)
+{
+
+	struct device *dev = to_dev(kobj);
+	struct device *parent_dev = dev->parent;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	struct Scsi_Host *shost = dev_to_shost(parent_dev);
+	int length = 0;
+	int i = 0;
+
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_TOPOLOGY_EVENT=1");
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_TOPOLOGY_EVENT_HCTL=1");
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_HOST=%u", shost->host_no);
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_CHANNEL=%u", sdev->channel);
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_ID=%u", sdev->id);
+	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
+			    "SCSI_LUN=%u", sdev->lun);
+
+	envp[i] = NULL;
+	return 0;
+}
+
+static struct kset_hotplug_ops scsi_topology_device_kset_ops +{
+	.hotplug = scsi_topology_device_hotplug,
+};
+
+static struct kset scsi_topology_device_kset = {
+	.hotplug_ops = &scsi_topology_device_kset_ops,
+	.kobj = {
+		.name = "scsi_topology",
+	},
+};
+
+static void scsi_topology_device_release(struct device *dev)
+{
+	put_device(dev->parent);
+}
+
+static int scsi_topology_device_init(struct scsi_device *sdev,
+				     struct Scsi_Host *shost,
+				     unsigned int channel,
+				     unsigned int id,
+				     unsigned int lun)
+{
+	struct device *dev;
+	memset(sdev, 0, sizeof(*sdev));
+	dev = &sdev->sdev_gendev;
+	snprintf(dev->bus_id, BUS_ID_SIZE, "topology-%u:%u:%u:%u",
+		 shost->host_no, channel, id, lun);
+	dev->parent     = get_device(&shost->shost_gendev);
+	dev->release    = scsi_topology_device_release;
+	sdev->channel = channel;
+	sdev->id = id;
+	sdev->lun = lun;
+	device_initialize(dev);
+	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
+	dev->kobj.parent = &dev->parent->kobj;
+	dev->kobj.kset  = &scsi_topology_device_kset;
+	return 0;
+}
+
+static inline enum kobject_action scsi_topology_action_to_kobject_action(enum scsi_topology_action action)
+{
+	enum kobject_action kaction = KOBJ_CHANGE; /* should there be a KOBJ_NOOP? */
+	switch (action)	{
+	case SCSI_TOPOLOGY_ADDED:
+		kaction = KOBJ_ADD;
+		break;
+	case SCSI_TOPOLOGY_REMOVED:
+		kaction = KOBJ_REMOVE;
+		break;
+	}
+	return kaction;
+}
+
+
+int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
+			      unsigned int id, unsigned int lun, enum scsi_topology_action action)
+{
+	struct scsi_device *sdev;
+	enum kobject_action kaction;
+	int error;
+
+	sdev = kmalloc(sizeof(*sdev), GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+	error = scsi_topology_device_init(sdev, shost, channel, id, lun);
+	if (error)
+		return error;
+	kaction = scsi_topology_action_to_kobject_action(action);
+	kobject_hotplug(&sdev->sdev_gendev.kobj, kaction);
+	kfree(sdev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_topology_hctl_action);


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

On Mon, Feb 07, 2005 at 12:27:53PM -0600, Matt Domsch wrote:
> Modified files:
> drivers/scsi/megaraid/megaraid_mbox.c
>  (will follow in a separate patch)
>  is the user of this new function.

For example.  I will rework this to follow the patch submitted last
week by LSI to accomplish something similar in their driver.

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

=== drivers/scsi/megaraid/megaraid_mbox.c 1.12 vs edited ==--- 1.12/drivers/scsi/megaraid/megaraid_mbox.c	2005-01-31 00:33:46 -06:00
+++ edited/drivers/scsi/megaraid/megaraid_mbox.c	2005-02-06 23:35:08 -06:00
@@ -70,6 +70,7 @@
  * For history of changes, see Documentation/ChangeLog.megaraid
  */
 
+#include <scsi/scsi_hotplug.h>
 #include "megaraid_mbox.h"
 
 static int megaraid_init(void);
@@ -455,6 +456,100 @@
 
 
 /*
+ * sysfs class device support
+ * creates three files:
+ * /sys/class/scsi_host
+ * |-- host0
+ * |   |-- logical_drive_created
+ * |   |-- logical_drive_destroyed
+ *
+ * These make the midlayer invoke /sbin/hotplug, which then calls back into sysfs
+ * /sys/class/scsi_host
+ * |-- host0
+ * |   |-- scan
+ *
+ * and
+ *
+ * /sys/devices/pci0000:0x/0000:0x:0x.0/host0
+ * |-- 0:0:0:0
+ * |   |-- delete
+ *
+ * respectively.  This allows userspace applications to work
+ * using their logical drive number, and lets the driver translate
+ * that into host, channel, id, and lun values which the other
+ * mechanisms require.  This is similar to how hot plug CPU works.
+ */
+
+/**
+ * lda_to_hcil()
+ * @adapter
+ * @lda - logical drive address
+ * @host_no
+ * @channel
+ * @id
+ * @lun
+ *
+ * converts a logical drive address into a host, channel id, lun tuple.
+ */
+
+static inline int megaraid_lda_to_hcil(struct Scsi_Host *shost, u32 lda,
+				       u32 *host_no, u32 *channel, u32 *id, u32 *lun)
+{
+	if (lda > MAX_LOGICAL_DRIVES_40LD)
+		return -EINVAL;
+	*host_no = shost->host_no;
+	*channel = shost->max_channel;
+	*id      = (lda < shost->this_id) ? lda : lda + 1;
+	*lun     = 0;
+	return 0;
+}
+
+static int megaraid_host_store(struct class_device *class_dev, const char *buf, size_t count,
+			       enum scsi_topology_action action)
+{
+        struct Scsi_Host *shost = class_to_shost(class_dev);
+	int fields=0, rc=-EINVAL;
+	u32 lda=0, host_no=0, channel=0, id=0, lun=0;
+	fields = sscanf(buf, "%u", &lda);
+	if (fields != 1)
+		return rc;
+	if (lda > MAX_LOGICAL_DRIVES_40LD)
+		return rc;
+	rc = megaraid_lda_to_hcil(shost, lda, &host_no, &channel, &id, &lun);
+	if (rc)
+		return rc;
+
+	rc = scsi_topology_hctl_action(shost, channel, id, lun, action);
+
+	if (rc)
+		return rc;
+	return count;
+}
+
+static ssize_t megaraid_host_store_ld_created(struct class_device *class_dev, const char *buf, size_t count)
+{
+	return megaraid_host_store(class_dev, buf, count, SCSI_TOPOLOGY_ADDED);
+}
+static ssize_t megaraid_host_store_ld_destroyed(struct class_device *class_dev, const char *buf, size_t count)
+{
+	return megaraid_host_store(class_dev, buf, count, SCSI_TOPOLOGY_REMOVED);
+}
+
+
+#define MEGARAID_HOST_WOATTR(_name,_store) \
+CLASS_DEVICE_ATTR(_name, S_IWUSR|S_IWGRP, NULL, _store)
+
+static MEGARAID_HOST_WOATTR(logical_drive_created, megaraid_host_store_ld_created);
+static MEGARAID_HOST_WOATTR(logical_drive_destroyed, megaraid_host_store_ld_destroyed);
+
+/* Host attributes initializer */
+static struct class_device_attribute *megaraid_host_attrs[] = {
+	&class_device_attr_logical_drive_created,
+	&class_device_attr_logical_drive_destroyed,
+	NULL,
+};
+
+/*
  * Scsi host template for megaraid unified driver
  */
 static struct scsi_host_template megaraid_template_g = {
@@ -467,6 +562,7 @@
 	.eh_bus_reset_handler		= megaraid_reset_handler,
 	.eh_host_reset_handler		= megaraid_reset_handler,
 	.use_clustering			= ENABLE_CLUSTERING,
+	.shost_attrs			= megaraid_host_attrs,
 };
 
 


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

On Mon, Feb 07, 2005 at 12:27:53PM -0600, Matt Domsch wrote:
> In addition, two more infrastructure pieces are necessary:
> udev-050-scsi_topology.patch - adds the subsystem name "scsi_topology"
> to the list of devices *not* to wait for the creation of files in
> sysfs for - scsi_topology devices aren't to be registered in sysfs.

Patch follows.

Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

--- udev-050/udev_sysfs.c.~1~	2004-12-17 23:53:07.000000000 -0600
+++ udev-050/udev_sysfs.c	2005-02-07 10:58:45.000000000 -0600
@@ -56,6 +56,7 @@
 	{ .subsystem = "fc_host",	.file = "port_id" },
 	{ .subsystem = "spi_transport",	.file = "width" },
 	{ .subsystem = "spi_host",	.file = "width" },
+	{ .subsystem = "scsi_topology",	.file = NULL },
 	{ NULL, NULL }
 };
 


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

On Mon, Feb 07, 2005 at 12:27:53PM -0600, Matt Domsch wrote:
> /etc/hotplug/scsi_topology.agent
>  handles the hotplug call, and invokes /sys/class/scsi_host/hostX/scan
>  and /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.

And here's scsi_topology.agent.

Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>

--
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

#!/bin/bash
#
# SCSI Topology hotplug agent.
# Copyright (C) 2005 Dell, Inc.  <Matt_Domsch@dell.com>
#
# This is invoked when a device, not currently known to the system, is
# added or removed from a SCSI topology.  This includes creation of a
# logical drive on a RAID controller, or manually inserting a disk
# into a SCSI disk enclosure.  This script then invokes the scan
# method of the scsi_host, or the delete method of the scsi_device, to
# inform the kernel of the change made on the topology.
#
# SCSI_TOPOLOGY_EVENT_HCTL is used to know that the data to pass to
# scan is a Host:Controller:Target ID:LUN tuple.  This is to provide
# for future SCSI implmentations that may use a native addressing
# scheme rather than only HCTL.


[ ${SCSI_TOPOLOGY_EVENT} != "1" ] && exit
[ ${SCSI_TOPOLOGY_EVENT_HCTL} != "1" ] && exit

if [ "${ACTION}" = "add" ]; then
    MYPATH=/sys/class/scsi_host/host${SCSI_HOST}/scan
    [ -f ${MYPATH} ] && echo "${SCSI_CHANNEL} ${SCSI_ID} ${SCSI_LUN}" > ${MYPATH}
fi

if [ "${ACTION}" = "remove" ]; then
    MYPATH=/sys/class/scsi_device/${SCSI_HOST}:${SCSI_CHANNEL}:${SCSI_ID}:${SCSI_LUN}/device/delete
    [ -f ${MYPATH} ] && echo "1" > ${MYPATH}
fi


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Brian King]

Matt Domsch wrote:
> Below is a patch to add some hotplug infrastructure to the Linux SCSI
> subsystem.
> 
> New files:
> include/scsi/scsi_hotplug.h
> drivers/scsi/scsi_hotplug.c
> implements a new exported function:
> 
> extern int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
> 			      unsigned int id, unsigned int lun, enum scsi_topology_action action);
> 
> which invokes kobject_hotplug() on a temporary "scsi_topology"
> device.  This device represents a target that exists on a topology
> (i.e. was just inserted into a hot plug enclosure, or was just created
> by a RAID controller management application) but is not yet hooked
> into the kernel.
> 
> 
> In addition, two more infrastructure pieces are necessary:
> udev-050-scsi_topology.patch - adds the subsystem name "scsi_topology"
> to the list of devices *not* to wait for the creation of files in
> sysfs for - scsi_topology devices aren't to be registered in sysfs.
> 
> /etc/hotplug/scsi_topology.agent
>  handles the hotplug call, and invokes /sys/class/scsi_host/hostX/scan
>  and /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.
> 
> 
> The flow is as follows:
> 
> # echo "2" > /sys/class/scsi_host/host2/logical_drive_created
> (to be done by a management application that knows it just created
> logical drive #2 on the controller)
> 
> megaraid_mbox.c sysfs method converts logical drive number to HCTL
> value, calls scsi_topology_hctl_action().
> 
> scsi_topology_hctl_action() invokes kobject_hotplug() with a
> scsi_topology subsystem device.
> 
> kobject_hotplug() calls /sbin/hotplug or /sbin/udevsend (more likely
> the latter), which invokes /etc/hotplug/scsi_topology.agent with the
> ACTION={add,remove}.
> 
> scsi_topology.agent invokes /sys/class/scsi_host/hostX/scan or
>  /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.
> 
> From this point, we're back into known territory, with the device
> being made known, or deleted from, the kernel's view.
> 
> Thoughts?

Just curious why the following flow would not work/be preferred:

1. echo "2" > /sys/class/scsi_host/host2/logical_drive_created
2. megaraid_mbox.c sysfs method converts logical drive number to HCTL 
value, calls scsi_add_device.
3. scsi_add_device works as it does today and generates hotplug events

-Brian

-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

On Mon, Feb 07, 2005 at 01:22:29PM -0600, Brian King wrote:
> Just curious why the following flow would not work/be preferred:
> 
> 1. echo "2" > /sys/class/scsi_host/host2/logical_drive_created
> 2. megaraid_mbox.c sysfs method converts logical drive number to HCTL 
> value, calls scsi_add_device.
> 3. scsi_add_device works as it does today and generates hotplug events
> 
> -Brian


This direction was what came out of this thread back in December.
http://marc.theaimsgroup.com/?l=linux-kernel&m\x110314267629902&w=2

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com


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Re: [RFC][PATCH 2.6.11-rc2] Linux SCSI hotplug infrastructure

[Matt Domsch]

On Mon, Feb 07, 2005 at 12:27:53PM -0600, Matt Domsch wrote:
> Below is a patch to add some hotplug infrastructure to the Linux SCSI
> subsystem.

I've added and reworked the megaraid_mbox driver to make use of this
new infrastructure.  I'll send that patch next.  The rest is unchanged
from yesterday.

I've put this work into a bkbits repo.  This is a clone of Linus's
linux-2.6, not of James' scsi-misc-2.6.
  
	bk pull http://mdomsch.bkbits.net/linux-2.6-scsi-hotplug

This will update the following files:

 Documentation/scsi/ChangeLog.megaraid  |  130 ++++++++
 drivers/scsi/Kconfig                   |   10 
 drivers/scsi/Makefile                  |    1 
 drivers/scsi/megaraid/Kconfig.megaraid |    1 
 drivers/scsi/megaraid/mega_common.h    |    3 
 drivers/scsi/megaraid/megaraid_ioctl.h |    1 
 drivers/scsi/megaraid/megaraid_mbox.c  |  500 +++++++++++++++++++++++++++++++--
 drivers/scsi/megaraid/megaraid_mbox.h  |   28 +
 drivers/scsi/megaraid/megaraid_mm.c    |   39 ++
 drivers/scsi/megaraid/megaraid_mm.h    |    5 
 drivers/scsi/scsi_hotplug.c            |  138 +++++++++
 include/scsi/scsi_hotplug.h            |   41 ++
 12 files changed, 867 insertions, 30 deletions

through these ChangeSets:

<Matt_Domsch@dell.com> (05/02/08 1.2132.2.3)
   Release Date	: Tue Feb 08 12:27:22 EST 2005 - Matt Domsch <Matt_Domsch@dell.com>
   Current Version	: 2.20.4.6 (scsi module), 2.20.2.5 (cmm module)
   Older Version	: 2.20.4.5 (scsi module), 2.20.2.5 (cmm module)
   
   1.	Added two new megaraid_shost_attrs
   	/sys/class/scsi_host
   	|-- host0
   	|   |-- logical_drive_created
   	|   |-- logical_drive_destroyed
   	
   	and helper functions for them.  Written to from userspace by
   	a management application, these invoke SCSI hotplug
   	infrastructure for informing the kernel that a logical drive
   	has been created, or will be destroyed quite soon.
   	    echo "2" > logical_drive_created
           after creating logical drive #2 in the management app
   	    echo "4" > logical_drive_destroyed
   	immediately before destroying logical drive #4 in the
   	management app.  Eventually these functions should be called
   	directly from the management app.
   
   2.	Made class_device_megaraid_mbox_app_hndl and
           dev_attr_megaraid_mbox_ld static.
   
   Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>

<Matt_Domsch@dell.com> (05/02/08 1.2132.2.2)
   megaraid_2.20.4.5.patch

<Matt_Domsch@dell.com> (05/02/07 1.2048.2.1)
   Below is a patch to add some hotplug infrastructure to the Linux SCSI
   subsystem.
   
   New files:
   include/scsi/scsi_hotplug.h
   drivers/scsi/scsi_hotplug.c
   implements a new exported function:
   
   extern int scsi_topology_hctl_action(struct Scsi_Host *shost, unsigned int channel,
   			      unsigned int id, unsigned int lun, enum scsi_topology_action action);
   
   which invokes kobject_hotplug() on a temporary "scsi_topology"
   device.  This device represents a target that exists on a topology
   (i.e. was just inserted into a hot plug enclosure, or was just created
   by a RAID controller management application) but is not yet hooked
   into the kernel.
   
   In addition, two more infrastructure pieces are necessary:
   udev-050-scsi_topology.patch - adds the subsystem name "scsi_topology"
   to the list of devices *not* to wait for the creation of files in
   sysfs for - scsi_topology devices aren't to be registered in sysfs.
   
   /etc/hotplug/scsi_topology.agent
    handles the hotplug call, and invokes /sys/class/scsi_host/hostX/scan
    and /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.
   
   
   The flow is as follows:
   
   # echo "2" > /sys/class/scsi_host/host2/logical_drive_created
   (to be done by a management application that knows it just created
   logical drive #2 on the controller)
   
   megaraid_mbox.c sysfs method converts logical drive number to HCTL
   value, calls scsi_topology_hctl_action().
   
   scsi_topology_hctl_action() invokes kobject_hotplug() with a
   scsi_topology subsystem device.
   
   kobject_hotplug() calls /sbin/hotplug or /sbin/udevsend (more likely
   the latter), which invokes /etc/hotplug/scsi_topology.agent with the
   ACTION={add,remove}.
   
   scsi_topology.agent invokes /sys/class/scsi_host/hostX/scan or
    /sys/class/scsi_device/H:C:T:L:/device/delete as appropriate.
   
   From this point, we're back into known territory, with the device
   being made known, or deleted from, the kernel's view.
   
   Signed-off-by: Matt Domsch <Matt_Domsch@dell.com>



-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com


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