drivers/scsi/scsi_dh.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * SCSI device handler infrastructure.
  *
  * Copyright IBM Corporation, 2007
  *      Authors:
  *               Chandra Seetharaman <sekharan@us.ibm.com>
  *               Mike Anderson <andmike@linux.vnet.ibm.com>
  */

 #include <linux/slab.h>
 #include <linux/module.h>
 #include <scsi/scsi_dh.h>
 #include "scsi_priv.h"

 static DEFINE_SPINLOCK(list_lock);
 static LIST_HEAD(scsi_dh_list);

 struct scsi_dh_blist {
 	const char *vendor;
 	const char *model;
 	const char *driver;
 };

 static const struct scsi_dh_blist scsi_dh_blist[] = {
 	{"DGC", "RAID",			"emc" },
 	{"DGC", "DISK",			"emc" },
 	{"DGC", "VRAID",		"emc" },

 	{"COMPAQ", "MSA1000 VOLUME",	"hp_sw" },
 	{"COMPAQ", "HSV110",		"hp_sw" },
 	{"HP", "HSV100",		"hp_sw"},
 	{"DEC", "HSG80",		"hp_sw"},

 	{"IBM", "1722",			"rdac", },
 	{"IBM", "1724",			"rdac", },
 	{"IBM", "1726",			"rdac", },
 	{"IBM", "1742",			"rdac", },
 	{"IBM", "1745",			"rdac", },
 	{"IBM", "1746",			"rdac", },
 	{"IBM", "1813",			"rdac", },
 	{"IBM", "1814",			"rdac", },
 	{"IBM", "1815",			"rdac", },
 	{"IBM", "1818",			"rdac", },
 	{"IBM", "3526",			"rdac", },
 	{"IBM", "3542",			"rdac", },
 	{"IBM", "3552",			"rdac", },
 	{"SGI", "TP9300",		"rdac", },
 	{"SGI", "TP9400",		"rdac", },
 	{"SGI", "TP9500",		"rdac", },
 	{"SGI", "TP9700",		"rdac", },
 	{"SGI", "IS",			"rdac", },
 	{"STK", "OPENstorage",		"rdac", },
 	{"STK", "FLEXLINE 380",		"rdac", },
 	{"STK", "BladeCtlr",		"rdac", },
 	{"SUN", "CSM",			"rdac", },
 	{"SUN", "LCSM100",		"rdac", },
 	{"SUN", "STK6580_6780",		"rdac", },
 	{"SUN", "SUN_6180",		"rdac", },
 	{"SUN", "ArrayStorage",		"rdac", },
 	{"DELL", "MD3",			"rdac", },
 	{"NETAPP", "INF-01-00",		"rdac", },
 	{"LSI", "INF-01-00",		"rdac", },
 	{"ENGENIO", "INF-01-00",	"rdac", },
 	{"LENOVO", "DE_Series",		"rdac", },
 	{"FUJITSU", "ETERNUS_AHB",	"rdac", },
 	{NULL, NULL,			NULL },
 };

 static const char *
 scsi_dh_find_driver(struct scsi_device *sdev)
 {
 	const struct scsi_dh_blist *b;

 	if (scsi_device_tpgs(sdev))
 		return "alua";

 	for (b = scsi_dh_blist; b->vendor; b++) {
 		if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
 		    !strncmp(sdev->model, b->model, strlen(b->model))) {
 			return b->driver;
 		}
 	}
 	return NULL;
 }


 static struct scsi_device_handler *__scsi_dh_lookup(const char *name)
 {
 	struct scsi_device_handler *tmp, *found = NULL;

 	spin_lock(&list_lock);
 	list_for_each_entry(tmp, &scsi_dh_list, list) {
 		if (!strncmp(tmp->name, name, strlen(tmp->name))) {
 			found = tmp;
 			break;
 		}
 	}
 	spin_unlock(&list_lock);
 	return found;
 }

 static struct scsi_device_handler *scsi_dh_lookup(const char *name)
 {
 	struct scsi_device_handler *dh;

 	if (!name || strlen(name) == 0)
 		return NULL;

 	dh = __scsi_dh_lookup(name);
 	if (!dh) {
 		request_module("scsi_dh_%s", name);
 		dh = __scsi_dh_lookup(name);
 	}

 	return dh;
 }

 /*
  * scsi_dh_handler_attach - Attach a device handler to a device
  * @sdev - SCSI device the device handler should attach to
  * @scsi_dh - The device handler to attach
  */
 static int scsi_dh_handler_attach(struct scsi_device *sdev,
 				  struct scsi_device_handler *scsi_dh)
 {
 	int error, ret = 0;

 	if (!try_module_get(scsi_dh->module))
 		return -EINVAL;

 	error = scsi_dh->attach(sdev);
 	if (error != SCSI_DH_OK) {
 		switch (error) {
 		case SCSI_DH_NOMEM:
 			ret = -ENOMEM;
 			break;
 		case SCSI_DH_RES_TEMP_UNAVAIL:
 			ret = -EAGAIN;
 			break;
 		case SCSI_DH_DEV_UNSUPP:
 		case SCSI_DH_NOSYS:
 			ret = -ENODEV;
 			break;
 		default:
 			ret = -EINVAL;
 			break;
 		}
 		if (ret != -ENODEV)
 			sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
 				    scsi_dh->name, error);
 		module_put(scsi_dh->module);
 	} else
 		sdev->handler = scsi_dh;

 	return ret;
 }

 /*
  * scsi_dh_handler_detach - Detach a device handler from a device
  * @sdev - SCSI device the device handler should be detached from
  */
 static void scsi_dh_handler_detach(struct scsi_device *sdev)
 {
 	sdev->handler->detach(sdev);
 	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
 	module_put(sdev->handler->module);
 }

 void scsi_dh_add_device(struct scsi_device *sdev)
 {
 	struct scsi_device_handler *devinfo = NULL;
 	const char *drv;

 	drv = scsi_dh_find_driver(sdev);
 	if (drv)
 		devinfo = __scsi_dh_lookup(drv);
 	/*
 	 * device_handler is optional, so ignore errors
 	 * from scsi_dh_handler_attach()
 	 */
 	if (devinfo)
 		(void)scsi_dh_handler_attach(sdev, devinfo);
 }

 void scsi_dh_release_device(struct scsi_device *sdev)
 {
 	if (sdev->handler)
 		scsi_dh_handler_detach(sdev);
 }

 /*
  * scsi_register_device_handler - register a device handler personality
  *      module.
  * @scsi_dh - device handler to be registered.
  *
  * Returns 0 on success, -EBUSY if handler already registered.
  */
 int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
 {
 	if (__scsi_dh_lookup(scsi_dh->name))
 		return -EBUSY;

 	if (!scsi_dh->attach || !scsi_dh->detach)
 		return -EINVAL;

 	spin_lock(&list_lock);
 	list_add(&scsi_dh->list, &scsi_dh_list);
 	spin_unlock(&list_lock);

 	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);

 	return SCSI_DH_OK;
 }
 EXPORT_SYMBOL_GPL(scsi_register_device_handler);

 /*
  * scsi_unregister_device_handler - register a device handler personality
  *      module.
  * @scsi_dh - device handler to be unregistered.
  *
  * Returns 0 on success, -ENODEV if handler not registered.
  */
 int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
 {
 	if (!__scsi_dh_lookup(scsi_dh->name))
 		return -ENODEV;

 	spin_lock(&list_lock);
 	list_del(&scsi_dh->list);
 	spin_unlock(&list_lock);
 	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);

 	return SCSI_DH_OK;
 }
 EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);

 /*
  * scsi_dh_activate - activate the path associated with the scsi_device
  *      corresponding to the given request queue.
  *     Returns immediately without waiting for activation to be completed.
  * @q    - Request queue that is associated with the scsi_device to be
  *         activated.
  * @fn   - Function to be called upon completion of the activation.
  *         Function fn is called with data (below) and the error code.
  *         Function fn may be called from the same calling context. So,
  *         do not hold the lock in the caller which may be needed in fn.
  * @data - data passed to the function fn upon completion.
  *
  */
 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 {
 	struct scsi_device *sdev;
 	int err = SCSI_DH_NOSYS;

 	sdev = scsi_device_from_queue(q);
 	if (!sdev) {
 		if (fn)
 			fn(data, err);
 		return err;
 	}

 	if (!sdev->handler)
 		goto out_fn;
 	err = SCSI_DH_NOTCONN;
 	if (sdev->sdev_state == SDEV_CANCEL ||
 	    sdev->sdev_state == SDEV_DEL)
 		goto out_fn;

 	err = SCSI_DH_DEV_OFFLINED;
 	if (sdev->sdev_state == SDEV_OFFLINE)
 		goto out_fn;

 	if (sdev->handler->activate)
 		err = sdev->handler->activate(sdev, fn, data);

 out_put_device:
 	put_device(&sdev->sdev_gendev);
 	return err;

 out_fn:
 	if (fn)
 		fn(data, err);
 	goto out_put_device;
 }
 EXPORT_SYMBOL_GPL(scsi_dh_activate);

 /*
  * scsi_dh_set_params - set the parameters for the device as per the
  *      string specified in params.
  * @q - Request queue that is associated with the scsi_device for
  *      which the parameters to be set.
  * @params - parameters in the following format
  *      "no_of_params\0param1\0param2\0param3\0...\0"
  *      for example, string for 2 parameters with value 10 and 21
  *      is specified as "2\010\021\0".
  */
 int scsi_dh_set_params(struct request_queue *q, const char *params)
 {
 	struct scsi_device *sdev;
 	int err = -SCSI_DH_NOSYS;

 	sdev = scsi_device_from_queue(q);
 	if (!sdev)
 		return err;

 	if (sdev->handler && sdev->handler->set_params)
 		err = sdev->handler->set_params(sdev, params);
 	put_device(&sdev->sdev_gendev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(scsi_dh_set_params);

 /*
  * scsi_dh_attach - Attach device handler
  * @q - Request queue that is associated with the scsi_device
  *      the handler should be attached to
  * @name - name of the handler to attach
  */
 int scsi_dh_attach(struct request_queue *q, const char *name)
 {
 	struct scsi_device *sdev;
 	struct scsi_device_handler *scsi_dh;
 	int err = 0;

 	sdev = scsi_device_from_queue(q);
 	if (!sdev)
 		return -ENODEV;

 	scsi_dh = scsi_dh_lookup(name);
 	if (!scsi_dh) {
 		err = -EINVAL;
 		goto out_put_device;
 	}

 	if (sdev->handler) {
 		if (sdev->handler != scsi_dh)
 			err = -EBUSY;
 		goto out_put_device;
 	}

 	err = scsi_dh_handler_attach(sdev, scsi_dh);

 out_put_device:
 	put_device(&sdev->sdev_gendev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(scsi_dh_attach);

 /*
  * scsi_dh_attached_handler_name - Get attached device handler's name
  * @q - Request queue that is associated with the scsi_device
  *      that may have a device handler attached
  * @gfp - the GFP mask used in the kmalloc() call when allocating memory
  *
  * Returns name of attached handler, NULL if no handler is attached.
  * Caller must take care to free the returned string.
  */
 const char *scsi_dh_attached_handler_name(struct request_queue *q, gfp_t gfp)
 {
 	struct scsi_device *sdev;
 	const char *handler_name = NULL;

 	sdev = scsi_device_from_queue(q);
 	if (!sdev)
 		return NULL;

 	if (sdev->handler)
 		handler_name = kstrdup(sdev->handler->name, gfp);
 	put_device(&sdev->sdev_gendev);
 	return handler_name;
 }
 EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* SCSI device handler infrastructure.
	*
	* Copyright IBM Corporation, 2007
	* Authors:
	* Chandra Seetharaman <sekharan@us.ibm.com>
	* Mike Anderson <andmike@linux.vnet.ibm.com>
	*/

	#include <linux/slab.h>
	#include <linux/module.h>
	#include <scsi/scsi_dh.h>
	#include "scsi_priv.h"

	static DEFINE_SPINLOCK(list_lock);
	static LIST_HEAD(scsi_dh_list);

	struct scsi_dh_blist {
	const char *vendor;
	const char *model;
	const char *driver;
	};

	static const struct scsi_dh_blist scsi_dh_blist[] = {
	{"DGC", "RAID", "emc" },
	{"DGC", "DISK", "emc" },
	{"DGC", "VRAID", "emc" },

	{"COMPAQ", "MSA1000 VOLUME", "hp_sw" },
	{"COMPAQ", "HSV110", "hp_sw" },
	{"HP", "HSV100", "hp_sw"},
	{"DEC", "HSG80", "hp_sw"},

	{"IBM", "1722", "rdac", },
	{"IBM", "1724", "rdac", },
	{"IBM", "1726", "rdac", },
	{"IBM", "1742", "rdac", },
	{"IBM", "1745", "rdac", },
	{"IBM", "1746", "rdac", },
	{"IBM", "1813", "rdac", },
	{"IBM", "1814", "rdac", },
	{"IBM", "1815", "rdac", },
	{"IBM", "1818", "rdac", },
	{"IBM", "3526", "rdac", },
	{"IBM", "3542", "rdac", },
	{"IBM", "3552", "rdac", },
	{"SGI", "TP9300", "rdac", },
	{"SGI", "TP9400", "rdac", },
	{"SGI", "TP9500", "rdac", },
	{"SGI", "TP9700", "rdac", },
	{"SGI", "IS", "rdac", },
	{"STK", "OPENstorage", "rdac", },
	{"STK", "FLEXLINE 380", "rdac", },
	{"STK", "BladeCtlr", "rdac", },
	{"SUN", "CSM", "rdac", },
	{"SUN", "LCSM100", "rdac", },
	{"SUN", "STK6580_6780", "rdac", },
	{"SUN", "SUN_6180", "rdac", },
	{"SUN", "ArrayStorage", "rdac", },
	{"DELL", "MD3", "rdac", },
	{"NETAPP", "INF-01-00", "rdac", },
	{"LSI", "INF-01-00", "rdac", },
	{"ENGENIO", "INF-01-00", "rdac", },
	{"LENOVO", "DE_Series", "rdac", },
	{"FUJITSU", "ETERNUS_AHB", "rdac", },
	{NULL, NULL, NULL },
	};

	static const char *
	scsi_dh_find_driver(struct scsi_device *sdev)
	{
	const struct scsi_dh_blist *b;

	if (scsi_device_tpgs(sdev))
	return "alua";

	for (b = scsi_dh_blist; b->vendor; b++) {
	if (!strncmp(sdev->vendor, b->vendor, strlen(b->vendor)) &&
	!strncmp(sdev->model, b->model, strlen(b->model))) {
	return b->driver;
	}
	}
	return NULL;
	}


	static struct scsi_device_handler __scsi_dh_lookup(const char name)
	{
	struct scsi_device_handler tmp, found = NULL;

	spin_lock(&list_lock);
	list_for_each_entry(tmp, &scsi_dh_list, list) {
	if (!strncmp(tmp->name, name, strlen(tmp->name))) {
	found = tmp;
	break;
	}
	}
	spin_unlock(&list_lock);
	return found;
	}

	static struct scsi_device_handler scsi_dh_lookup(const char name)
	{
	struct scsi_device_handler *dh;

	if (!name \|\| strlen(name) == 0)
	return NULL;

	dh = __scsi_dh_lookup(name);
	if (!dh) {
	request_module("scsi_dh_%s", name);
	dh = __scsi_dh_lookup(name);
	}

	return dh;
	}

	/*
	* scsi_dh_handler_attach - Attach a device handler to a device
	* @sdev - SCSI device the device handler should attach to
	* @scsi_dh - The device handler to attach
	*/
	static int scsi_dh_handler_attach(struct scsi_device *sdev,
	struct scsi_device_handler *scsi_dh)
	{
	int error, ret = 0;

	if (!try_module_get(scsi_dh->module))
	return -EINVAL;

	error = scsi_dh->attach(sdev);
	if (error != SCSI_DH_OK) {
	switch (error) {
	case SCSI_DH_NOMEM:
	ret = -ENOMEM;
	break;
	case SCSI_DH_RES_TEMP_UNAVAIL:
	ret = -EAGAIN;
	break;
	case SCSI_DH_DEV_UNSUPP:
	case SCSI_DH_NOSYS:
	ret = -ENODEV;
	break;
	default:
	ret = -EINVAL;
	break;
	}
	if (ret != -ENODEV)
	sdev_printk(KERN_ERR, sdev, "%s: Attach failed (%d)\n",
	scsi_dh->name, error);
	module_put(scsi_dh->module);
	} else
	sdev->handler = scsi_dh;

	return ret;
	}

	/*
	* scsi_dh_handler_detach - Detach a device handler from a device
	* @sdev - SCSI device the device handler should be detached from
	*/
	static void scsi_dh_handler_detach(struct scsi_device *sdev)
	{
	sdev->handler->detach(sdev);
	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", sdev->handler->name);
	module_put(sdev->handler->module);
	}

	void scsi_dh_add_device(struct scsi_device *sdev)
	{
	struct scsi_device_handler *devinfo = NULL;
	const char *drv;

	drv = scsi_dh_find_driver(sdev);
	if (drv)
	devinfo = __scsi_dh_lookup(drv);
	/*
	* device_handler is optional, so ignore errors
	* from scsi_dh_handler_attach()
	*/
	if (devinfo)
	(void)scsi_dh_handler_attach(sdev, devinfo);
	}

	void scsi_dh_release_device(struct scsi_device *sdev)
	{
	if (sdev->handler)
	scsi_dh_handler_detach(sdev);
	}

	/*
	* scsi_register_device_handler - register a device handler personality
	* module.
	* @scsi_dh - device handler to be registered.
	*
	* Returns 0 on success, -EBUSY if handler already registered.
	*/
	int scsi_register_device_handler(struct scsi_device_handler *scsi_dh)
	{
	if (__scsi_dh_lookup(scsi_dh->name))
	return -EBUSY;

	if (!scsi_dh->attach \|\| !scsi_dh->detach)
	return -EINVAL;

	spin_lock(&list_lock);
	list_add(&scsi_dh->list, &scsi_dh_list);
	spin_unlock(&list_lock);

	printk(KERN_INFO "%s: device handler registered\n", scsi_dh->name);

	return SCSI_DH_OK;
	}
	EXPORT_SYMBOL_GPL(scsi_register_device_handler);

	/*
	* scsi_unregister_device_handler - register a device handler personality
	* module.
	* @scsi_dh - device handler to be unregistered.
	*
	* Returns 0 on success, -ENODEV if handler not registered.
	*/
	int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh)
	{
	if (!__scsi_dh_lookup(scsi_dh->name))
	return -ENODEV;

	spin_lock(&list_lock);
	list_del(&scsi_dh->list);
	spin_unlock(&list_lock);
	printk(KERN_INFO "%s: device handler unregistered\n", scsi_dh->name);

	return SCSI_DH_OK;
	}
	EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);

	/*
	* scsi_dh_activate - activate the path associated with the scsi_device
	* corresponding to the given request queue.
	* Returns immediately without waiting for activation to be completed.
	* @q - Request queue that is associated with the scsi_device to be
	* activated.
	* @fn - Function to be called upon completion of the activation.
	* Function fn is called with data (below) and the error code.
	* Function fn may be called from the same calling context. So,
	* do not hold the lock in the caller which may be needed in fn.
	* @data - data passed to the function fn upon completion.
	*
	*/
	int scsi_dh_activate(struct request_queue q, activate_complete fn, void data)
	{
	struct scsi_device *sdev;
	int err = SCSI_DH_NOSYS;

	sdev = scsi_device_from_queue(q);
	if (!sdev) {
	if (fn)
	fn(data, err);
	return err;
	}

	if (!sdev->handler)
	goto out_fn;
	err = SCSI_DH_NOTCONN;
	if (sdev->sdev_state == SDEV_CANCEL \|\|
	sdev->sdev_state == SDEV_DEL)
	goto out_fn;

	err = SCSI_DH_DEV_OFFLINED;
	if (sdev->sdev_state == SDEV_OFFLINE)
	goto out_fn;

	if (sdev->handler->activate)
	err = sdev->handler->activate(sdev, fn, data);

	out_put_device:
	put_device(&sdev->sdev_gendev);
	return err;

	out_fn:
	if (fn)
	fn(data, err);
	goto out_put_device;
	}
	EXPORT_SYMBOL_GPL(scsi_dh_activate);

	/*
	* scsi_dh_set_params - set the parameters for the device as per the
	* string specified in params.
	* @q - Request queue that is associated with the scsi_device for
	* which the parameters to be set.
	* @params - parameters in the following format
	* "no_of_params\0param1\0param2\0param3\0...\0"
	* for example, string for 2 parameters with value 10 and 21
	* is specified as "2\010\021\0".
	*/
	int scsi_dh_set_params(struct request_queue q, const char params)
	{
	struct scsi_device *sdev;
	int err = -SCSI_DH_NOSYS;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
	return err;

	if (sdev->handler && sdev->handler->set_params)
	err = sdev->handler->set_params(sdev, params);
	put_device(&sdev->sdev_gendev);
	return err;
	}
	EXPORT_SYMBOL_GPL(scsi_dh_set_params);

	/*
	* scsi_dh_attach - Attach device handler
	* @q - Request queue that is associated with the scsi_device
	* the handler should be attached to
	* @name - name of the handler to attach
	*/
	int scsi_dh_attach(struct request_queue q, const char name)
	{
	struct scsi_device *sdev;
	struct scsi_device_handler *scsi_dh;
	int err = 0;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
	return -ENODEV;

	scsi_dh = scsi_dh_lookup(name);
	if (!scsi_dh) {
	err = -EINVAL;
	goto out_put_device;
	}

	if (sdev->handler) {
	if (sdev->handler != scsi_dh)
	err = -EBUSY;
	goto out_put_device;
	}

	err = scsi_dh_handler_attach(sdev, scsi_dh);

	out_put_device:
	put_device(&sdev->sdev_gendev);
	return err;
	}
	EXPORT_SYMBOL_GPL(scsi_dh_attach);

	/*
	* scsi_dh_attached_handler_name - Get attached device handler's name
	* @q - Request queue that is associated with the scsi_device
	* that may have a device handler attached
	* @gfp - the GFP mask used in the kmalloc() call when allocating memory
	*
	* Returns name of attached handler, NULL if no handler is attached.
	* Caller must take care to free the returned string.
	*/
	const char scsi_dh_attached_handler_name(struct request_queue q, gfp_t gfp)
	{
	struct scsi_device *sdev;
	const char *handler_name = NULL;

	sdev = scsi_device_from_queue(q);
	if (!sdev)
	return NULL;

	if (sdev->handler)
	handler_name = kstrdup(sdev->handler->name, gfp);
	put_device(&sdev->sdev_gendev);
	return handler_name;
	}
	EXPORT_SYMBOL_GPL(scsi_dh_attached_handler_name);