[PATCH ver2 05/16] osd_uld: OSD scsi ULD

[Boaz Harrosh <bharrosh@panasas.com>]

Add a Linux driver module that registers as a SCSI ULD and probes
for OSD type SCSI devices.

When an OSD-type SCSI device is found a character device is created
in the form of /dev/osdX - where X goes from 0 up to hard coded 64.
The Major character device number used is *260*, which is free
(as of Linux v2.6.28).

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Reviewed-by: Benny Halevy <bhalevy@panasas.com>
---
 drivers/scsi/osd/Kbuild    |    7 +
 drivers/scsi/osd/osd_uld.c |  383 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 390 insertions(+), 0 deletions(-)
 create mode 100644 drivers/scsi/osd/osd_uld.c

diff --git a/drivers/scsi/osd/Kbuild b/drivers/scsi/osd/Kbuild
index 5672842..4730cdc 100644
--- a/drivers/scsi/osd/Kbuild
+++ b/drivers/scsi/osd/Kbuild
@@ -17,6 +17,9 @@ ifneq ($(OSD_INC),)
 CONFIG_SCSI_OSD_INITIATOR=m
 ccflags-y += -DCONFIG_SCSI_OSD_INITIATOR -DCONFIG_SCSI_OSD_INITIATOR_MODULE
 
+CONFIG_SCSI_OSD_ULD=m
+ccflags-y += -DCONFIG_SCSI_OSD_ULD -DCONFIG_SCSI_OSD_ULD_MODULE
+
 # Uncomment to turn debug on
 # ccflags-y += -DCONFIG_SCSI_OSD_DEBUG
 
@@ -30,3 +33,7 @@ endif
 # libosd.ko - osd-initiator library
 libosd-y := osd_initiator.o
 obj-$(CONFIG_SCSI_OSD_INITIATOR) += libosd.o
+
+# osd.ko - SCSI ULD and char-device
+osd-y := osd_uld.o
+obj-$(CONFIG_SCSI_OSD_ULD) += osd.o
diff --git a/drivers/scsi/osd/osd_uld.c b/drivers/scsi/osd/osd_uld.c
new file mode 100644
index 0000000..fe86f08
--- /dev/null
+++ b/drivers/scsi/osd/osd_uld.c
@@ -0,0 +1,383 @@
+/*
+ * osd_uld.c - OSD Upper Layer Driver
+ *
+ * A Linux driver module that registers as a SCSI ULD and probes
+ * for OSD type SCSI devices.
+ * It's main function is to export osd devices to in-kernel users like
+ * osdfs and pNFS-objects-LD. It also provides one ioctl for running
+ * in Kernel tests.
+ *
+ * Copyright (C) 2008 Panasas Inc.  All rights reserved.
+ *
+ * Authors:
+ *   Boaz Harrosh <bharrosh@panasas.com>
+ *   Benny Halevy <bhalevy@panasas.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the Panasas company nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/major.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_ioctl.h>
+
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_sec.h>
+
+#include "osd_debug.h"
+
+#ifndef TYPE_OSD
+#  define TYPE_OSD 0x11
+#endif
+
+#ifndef SCSI_OSD_MAJOR
+#  define SCSI_OSD_MAJOR 260
+#endif
+#define SCSI_OSD_MAX_MINOR 64
+
+static const char osd_name[] = "osd";
+static const char *osd_version_string = "open-osd 0.1.0";
+const char osd_symlink[] = "scsi_osd";
+
+MODULE_AUTHOR("Boaz Harrosh <bharrosh@panasas.com>");
+MODULE_DESCRIPTION("open-osd Upper-Layer-Driver osd.ko");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_CHARDEV_MAJOR(SCSI_OSD_MAJOR);
+MODULE_ALIAS_SCSI_DEVICE(TYPE_OSD);
+
+struct osd_uld_device {
+	int minor;
+	struct kref kref;
+	struct cdev cdev;
+	struct osd_dev od;
+	struct gendisk *disk;
+	struct device *class_member;
+};
+
+static void __uld_get(struct osd_uld_device *oud);
+static void __uld_put(struct osd_uld_device *oud);
+
+/*
+ * Char Device operations
+ */
+
+static int osd_uld_open(struct inode *inode, struct file *file)
+{
+	struct osd_uld_device *oud = container_of(inode->i_cdev,
+					struct osd_uld_device, cdev);
+
+	__uld_get(oud);
+	/* cache osd_uld_device on file handle */
+	file->private_data = oud;
+	OSD_DEBUG("osd_uld_open %p\n", oud);
+	return 0;
+}
+
+static int osd_uld_release(struct inode *inode, struct file *file)
+{
+	struct osd_uld_device *oud = file->private_data;
+
+	OSD_DEBUG("osd_uld_release %p\n", file->private_data);
+	file->private_data = NULL;
+	__uld_put(oud);
+	return 0;
+}
+
+static long osd_uld_ioctl(struct file *file, unsigned int cmd,
+	unsigned long arg)
+{
+	struct osd_uld_device *oud = file->private_data;
+	int ret;
+
+	switch (cmd) {
+	default:
+		OSD_ERR("Unknown ioctl %d: osd_uld_device=%p\n", cmd, oud);
+		ret = -ENOIOCTLCMD;
+	}
+	return ret;
+}
+
+static const struct file_operations osd_fops = {
+	.owner          = THIS_MODULE,
+	.open           = osd_uld_open,
+	.release        = osd_uld_release,
+	.unlocked_ioctl = osd_uld_ioctl,
+};
+
+/*
+ * Scsi Device operations
+ */
+
+static int __detect_osd(struct osd_uld_device *oud)
+{
+	struct scsi_device *scsi_device = oud->od.scsi_device;
+	int error;
+
+	/* sending a test_unit_ready as first command seems to be needed
+	 * by some targets
+	 */
+	OSD_DEBUG("start scsi_test_unit_ready %p %p %p\n",
+			oud, scsi_device, scsi_device->request_queue);
+	error = scsi_test_unit_ready(scsi_device, 10*HZ, 5, NULL);
+	if (error)
+		OSD_ERR("warning: scsi_test_unit_ready failed\n");
+
+	return 0;
+}
+
+static struct class *osd_sysfs_class;
+static DEFINE_IDA(osd_minor_ida);
+
+static int osd_probe(struct device *dev)
+{
+	struct scsi_device *scsi_device = to_scsi_device(dev);
+	struct gendisk *disk;
+	struct osd_uld_device *oud;
+	int minor;
+	int error;
+
+	if (scsi_device->type != TYPE_OSD)
+		return -ENODEV;
+
+	do {
+		if (!ida_pre_get(&osd_minor_ida, GFP_KERNEL))
+			return -ENODEV;
+
+		error = ida_get_new(&osd_minor_ida, &minor);
+	} while (error == -EAGAIN);
+
+	if (error)
+		return error;
+	if (minor >= SCSI_OSD_MAX_MINOR) {
+		error = -EBUSY;
+		goto err_retract_minor;
+	}
+
+	error = -ENOMEM;
+	oud = kzalloc(sizeof(*oud), GFP_KERNEL);
+	if (NULL == oud)
+		goto err_retract_minor;
+
+	kref_init(&oud->kref);
+	dev_set_drvdata(dev, oud);
+	oud->minor = minor;
+
+	/* allocate a disk and set it up */
+	/* FIXME: do we need this since sg has already done that */
+	disk = alloc_disk(1);
+	if (!disk) {
+		OSD_ERR("alloc_disk failed\n");
+		goto err_free_osd;
+	}
+	disk->major = SCSI_OSD_MAJOR;
+	disk->first_minor = oud->minor;
+	sprintf(disk->disk_name, "osd%d", oud->minor);
+	oud->disk = disk;
+
+	/* hold one more reference to the scsi_device that will get released
+	 * in __release, in case a logout is happening while fs is mounted
+	 */
+	scsi_device_get(scsi_device);
+	osd_dev_init(&oud->od, scsi_device);
+
+	/* Detect the OSD Version */
+	error = __detect_osd(oud);
+	if (error) {
+		OSD_ERR("osd detection failed, non-compatible OSD device\n");
+		goto err_put_disk;
+	}
+
+	/* init the char-device for communication with user-mode */
+	cdev_init(&oud->cdev, &osd_fops);
+	oud->cdev.owner = THIS_MODULE;
+	error = cdev_add(&oud->cdev,
+			 MKDEV(SCSI_OSD_MAJOR, oud->minor), 1);
+	if (error) {
+		OSD_ERR("cdev_add failed\n");
+		goto err_put_disk;
+	}
+	kobject_get(&oud->cdev.kobj); /* 2nd ref see osd_remove() */
+
+	/* class_member */
+	oud->class_member = device_create(osd_sysfs_class, dev,
+		MKDEV(SCSI_OSD_MAJOR, oud->minor), "%s", disk->disk_name);
+	if (IS_ERR(oud->class_member)) {
+		OSD_ERR("class_device_create failed\n");
+		error = PTR_ERR(oud->class_member);
+		goto err_put_cdev;
+	}
+
+	dev_set_drvdata(oud->class_member, oud);
+	error = sysfs_create_link(&scsi_device->sdev_gendev.kobj,
+				  &oud->class_member->kobj, osd_symlink);
+	if (error)
+		OSD_ERR("warning: unable to make symlink\n");
+
+	OSD_INFO("osd_probe %s\n", disk->disk_name);
+	return 0;
+
+err_put_cdev:
+	cdev_del(&oud->cdev);
+err_put_disk:
+	scsi_device_put(scsi_device);
+	put_disk(disk);
+err_free_osd:
+	dev_set_drvdata(dev, NULL);
+	kfree(oud);
+err_retract_minor:
+	ida_remove(&osd_minor_ida, minor);
+	return error;
+}
+
+static int osd_remove(struct device *dev)
+{
+	struct scsi_device *scsi_device = to_scsi_device(dev);
+	struct osd_uld_device *oud = dev_get_drvdata(dev);
+
+	if (!oud || (oud->od.scsi_device != scsi_device)) {
+		OSD_ERR("Half cooked osd-device %p,%p || %p!=%p",
+			dev, oud, oud ? oud->od.scsi_device : NULL,
+			scsi_device);
+	}
+
+	sysfs_remove_link(&oud->od.scsi_device->sdev_gendev.kobj, osd_symlink);
+
+	if (oud->class_member)
+		device_destroy(osd_sysfs_class,
+			       MKDEV(SCSI_OSD_MAJOR, oud->minor));
+
+	/* We have 2 references to the cdev. One is released here
+	 * and also takes down the /dev/osdX mapping. The second
+	 * Will be released in __remove() after all users have released
+	 * the osd_uld_device.
+	 */
+	if (oud->cdev.owner)
+		cdev_del(&oud->cdev);
+
+	__uld_put(oud);
+	return 0;
+}
+
+static void __remove(struct kref *kref)
+{
+	struct osd_uld_device *oud = container_of(kref,
+					struct osd_uld_device, kref);
+	struct scsi_device *scsi_device = oud->od.scsi_device;
+
+	/* now let delete the char_dev */
+	kobject_put(&oud->cdev.kobj);
+
+	osd_dev_fini(&oud->od);
+	scsi_device_put(scsi_device);
+
+	OSD_INFO("osd_remove %s\n",
+		 oud->disk ? oud->disk->disk_name : NULL);
+
+	if (oud->disk)
+		put_disk(oud->disk);
+
+	ida_remove(&osd_minor_ida, oud->minor);
+	kfree(oud);
+}
+
+static void __uld_get(struct osd_uld_device *oud)
+{
+	kref_get(&oud->kref);
+}
+
+static void __uld_put(struct osd_uld_device *oud)
+{
+	kref_put(&oud->kref, __remove);
+}
+
+/*
+ * Global driver and scsi registration
+ */
+
+static struct scsi_driver osd_driver = {
+	.owner			= THIS_MODULE,
+	.gendrv = {
+		.name		= osd_name,
+		.probe		= osd_probe,
+		.remove		= osd_remove,
+	}
+};
+
+static int __init osd_uld_init(void)
+{
+	int err;
+
+	osd_sysfs_class = class_create(THIS_MODULE, osd_symlink);
+	if (IS_ERR(osd_sysfs_class)) {
+		OSD_ERR("Unable to register sysfs class => %ld\n",
+			PTR_ERR(osd_sysfs_class));
+		return PTR_ERR(osd_sysfs_class);
+	}
+
+	err = register_chrdev_region(MKDEV(SCSI_OSD_MAJOR, 0),
+				     SCSI_OSD_MAX_MINOR, osd_name);
+	if (err) {
+		OSD_ERR("Unable to register major %d for osd ULD => %d\n",
+			SCSI_OSD_MAJOR, err);
+		goto err_out;
+	}
+
+	err = scsi_register_driver(&osd_driver.gendrv);
+	if (err) {
+		OSD_ERR("scsi_register_driver failed => %d\n", err);
+		goto err_out_chrdev;
+	}
+
+	OSD_INFO("LOADED %s\n", osd_version_string);
+	return 0;
+
+err_out_chrdev:
+	unregister_chrdev_region(MKDEV(SCSI_OSD_MAJOR, 0), SCSI_OSD_MAX_MINOR);
+err_out:
+	class_destroy(osd_sysfs_class);
+	return err;
+}
+
+static void __exit osd_uld_exit(void)
+{
+	scsi_unregister_driver(&osd_driver.gendrv);
+	unregister_chrdev_region(MKDEV(SCSI_OSD_MAJOR, 0), SCSI_OSD_MAX_MINOR);
+	class_destroy(osd_sysfs_class);
+	OSD_INFO("UNLOADED %s\n", osd_version_string);
+}
+
+module_init(osd_uld_init);
+module_exit(osd_uld_exit);
-- 
1.6.0.1