scsi: remove the old scsi_module.c initialization model

After more than 15 years all users of this legacy interface are finally
gone.  Rest in peace!
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Documentation/driver-api/scsi.rst

@@ -154,12 +154,6 @@ lists).
 .. kernel-doc:: drivers/scsi/scsi_lib_dma.c
    :export:
 
-drivers/scsi/scsi_module.c
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The file drivers/scsi/scsi_module.c contains legacy support for
-old-style host templates. It should never be used by any new driver.
-
 drivers/scsi/scsi_proc.c
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 

Documentation/scsi/scsi_mid_low_api.txt

@@ -114,9 +114,7 @@ called "xxx" could be defined as
 "static int xxx_slave_alloc(struct scsi_device * sdev) { /* code */ }"
 
 ** the scsi_host_alloc() function is a replacement for the rather vaguely
-named scsi_register() function in most situations. The scsi_register()
-and scsi_unregister() functions remain to support legacy LLDs that use
-the passive initialization model.
+named scsi_register() function in most situations.
 
 
 Hotplug initialization model
@@ -228,79 +226,6 @@ slave_configure() callbacks). Such instances are "owned" by the mid-level.
 struct scsi_device instances are freed after slave_destroy().
 
 
-Passive initialization model
-============================
-These older LLDs include a file called "scsi_module.c" [yes the ".c" is a
-little surprising] in their source code. For that file to work an
-instance of struct scsi_host_template with the name "driver_template"
-needs to be defined. Here is a typical code sequence used in this model:
-    static struct scsi_host_template driver_template = {
-        ...
-    };
-    #include "scsi_module.c"
-
-The scsi_module.c file contains two functions:
-  - init_this_scsi_driver() which is executed when the LLD is
-    initialized (i.e. boot time or module load time)
-  - exit_this_scsi_driver() which is executed when the LLD is shut
-    down (i.e. module unload time)
-Note: since these functions are tagged with __init and __exit qualifiers
-an LLD should not call them explicitly (since the kernel does that).
-
-Here is an example of an initialization sequence when two hosts are
-detected (so detect() returns 2) and the SCSI bus scan on each host
-finds 1 SCSI device (and a second device does not respond).
-
-LLD                      mid level                 LLD
-===----------------------=========-----------------===------
-init_this_scsi_driver() ----+
-                            |
-                         detect()  -----------------+
-                            |                       |
-                            |                scsi_register()
-                            |                scsi_register()
-                            |
-                      slave_alloc()
-                      slave_configure()  -->  scsi_change_queue_depth()
-                      slave_alloc()   ***
-                      slave_destroy() ***
-                            |
-                      slave_alloc()
-                      slave_configure()
-                      slave_alloc()   ***
-                      slave_destroy() ***
-------------------------------------------------------------
-
-The mid level invokes scsi_change_queue_depth() with "cmd_per_lun" for that
-host as the queue length. These settings can be overridden by a
-slave_configure() supplied by the LLD.
-
-*** For scsi devices that the mid level tries to scan but do not
-    respond, a slave_alloc(), slave_destroy() pair is called.
-
-Here is an LLD shutdown sequence:
-
-LLD                      mid level                 LLD
-===----------------------=========-----------------===------
-exit_this_scsi_driver() ----+
-                            |
-                     slave_destroy()
-                        release()   -->   scsi_unregister()
-                            |
-                     slave_destroy()
-                        release()   -->   scsi_unregister()
-------------------------------------------------------------
-
-An LLD need not define slave_destroy() (i.e. it is optional). 
-
-The shortcoming of the "passive initialization model" is that host
-registration and de-registration are (typically) tied to LLD initialization
-and shutdown. Once the LLD is initialized then a new host that appears
-(e.g. via hotplugging) cannot easily be added without a redundant
-driver shutdown and re-initialization. It may be possible to write an LLD
-that uses both initialization models.
-
-
 Reference Counting
 ==================
 The Scsi_Host structure has had reference counting infrastructure added.
@@ -738,7 +663,6 @@ The interface functions are listed below in alphabetical order.
 
 Summary:
    bios_param - fetch head, sector, cylinder info for a disk
-   detect - detects HBAs this driver wants to control
    eh_timed_out - notify the host that a command timer expired
    eh_abort_handler - abort given command
    eh_bus_reset_handler - issue SCSI bus reset
@@ -748,7 +672,6 @@ Summary:
    ioctl - driver can respond to ioctls
    proc_info - supports /proc/scsi/{driver_name}/{host_no}
    queuecommand - queue scsi command, invoke 'done' on completion
-   release - release all resources associated with given host
    slave_alloc - prior to any commands being sent to a new device 
    slave_configure - driver fine tuning for given device after attach
    slave_destroy - given device is about to be shut down
@@ -784,28 +707,6 @@ Details:
                    sector_t capacity, int params[3])
 
 
-/**
- *      detect - detects HBAs this driver wants to control
- *      @shtp: host template for this driver.
- *
- *      Returns number of hosts this driver wants to control. 0 means no
- *      suitable hosts found.
- *
- *      Locks: none held
- *
- *      Calling context: process [invoked from init_this_scsi_driver()]
- *
- *      Notes: First function called from the SCSI mid level on this
- *      driver. Upper level drivers (e.g. sd) may not (yet) be present.
- *      For each host found, this method should call scsi_register() 
- *      [see hosts.c].
- *
- *      Defined in: LLD (required if "passive initialization mode" is used,
- *                       not invoked in "hotplug initialization mode")
- **/
-    int detect(struct scsi_host_template * shtp)
-
-
 /**
  *      eh_timed_out - The timer for the command has just fired
  *      @scp: identifies command timing out
@@ -1073,27 +974,6 @@ Details:
     int queuecommand(struct Scsi_Host *shost, struct scsi_cmnd * scp)
 
 
-/**
- *      release - release all resources associated with given host
- *      @shp: host to be released.
- *
- *      Return value ignored (could soon be a function returning void).
- *
- *      Locks: none held
- *
- *      Calling context: process
- *
- *      Notes: Invoked from scsi_module.c's exit_this_scsi_driver().
- *      LLD's implementation of this function should call 
- *      scsi_unregister(shp) prior to returning.
- *      Only needed for old-style host templates.
- *
- *      Defined in: LLD (required in "passive initialization model",
- *                       should not be defined in hotplug model)
- **/
-    int release(struct Scsi_Host * shp)
-
-
 /**
  *      slave_alloc -   prior to any commands being sent to a new device 
  *                      (i.e. just prior to scan) this call is made

drivers/scsi/hosts.c

@@ -518,29 +518,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 }
 EXPORT_SYMBOL(scsi_host_alloc);
 
-struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
-{
-	struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
-
-	if (!sht->detect) {
-		printk(KERN_WARNING "scsi_register() called on new-style "
-				    "template for driver %s\n", sht->name);
-		dump_stack();
-	}
-
-	if (shost)
-		list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
-	return shost;
-}
-EXPORT_SYMBOL(scsi_register);
-
-void scsi_unregister(struct Scsi_Host *shost)
-{
-	list_del(&shost->sht_legacy_list);
-	scsi_host_put(shost);
-}
-EXPORT_SYMBOL(scsi_unregister);
-
 static int __scsi_host_match(struct device *dev, const void *data)
 {
 	struct Scsi_Host *p;

drivers/scsi/scsi_module.c

-/*
- * Copyright (C) 2003 Christoph Hellwig.
- *	Released under GPL v2.
- *
- * Support for old-style host templates.
- *
- * NOTE:  Do not use this for new drivers ever.
- */
-
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-
-#include <scsi/scsi_host.h>
-
-
-static int __init init_this_scsi_driver(void)
-{
-	struct scsi_host_template *sht = &driver_template;
-	struct Scsi_Host *shost;
-	struct list_head *l;
-	int error;
-
-	if (!sht->release) {
-		printk(KERN_ERR
-		    "scsi HBA driver %s didn't set a release method.\n",
-		    sht->name);
-		return -EINVAL;
-	}
-
-	sht->module = THIS_MODULE;
-	INIT_LIST_HEAD(&sht->legacy_hosts);
-
-	sht->detect(sht);
-	if (list_empty(&sht->legacy_hosts))
-		return -ENODEV;
-
-	list_for_each_entry(shost, &sht->legacy_hosts, sht_legacy_list) {
-		error = scsi_add_host(shost, NULL);
-		if (error)
-			goto fail;
-		scsi_scan_host(shost);
-	}
-	return 0;
- fail:
-	l = &shost->sht_legacy_list;
-	while ((l = l->prev) != &sht->legacy_hosts)
-		scsi_remove_host(list_entry(l, struct Scsi_Host, sht_legacy_list));
-	return error;
-}
-
-static void __exit exit_this_scsi_driver(void)
-{
-	struct scsi_host_template *sht = &driver_template;
-	struct Scsi_Host *shost, *s;
-
-	list_for_each_entry(shost, &sht->legacy_hosts, sht_legacy_list)
-		scsi_remove_host(shost);
-	list_for_each_entry_safe(shost, s, &sht->legacy_hosts, sht_legacy_list)
-		sht->release(shost);
-
-	if (list_empty(&sht->legacy_hosts))
-		return;
-
-	printk(KERN_WARNING "%s did not call scsi_unregister\n", sht->name);
-	dump_stack();
-
-	list_for_each_entry_safe(shost, s, &sht->legacy_hosts, sht_legacy_list)
-		scsi_unregister(shost);
-}
-
-module_init(init_this_scsi_driver);
-module_exit(exit_this_scsi_driver);

include/scsi/scsi_host.h

@@ -51,21 +51,6 @@ struct scsi_host_template {
 	struct module *module;
 	const char *name;
 
-	/*
-	 * Used to initialize old-style drivers.  For new-style drivers
-	 * just perform all work in your module initialization function.
-	 *
-	 * Status:  OBSOLETE
-	 */
-	int (* detect)(struct scsi_host_template *);
-
-	/*
-	 * Used as unload callback for hosts with old-style drivers.
-	 *
-	 * Status: OBSOLETE
-	 */
-	int (* release)(struct Scsi_Host *);
-
 	/*
 	 * The info function will return whatever useful information the
 	 * developer sees fit.  If not provided, then the name field will
@@ -482,15 +467,6 @@ struct scsi_host_template {
 	 */
 	const struct attribute_group **sdev_groups;
 
-	/*
-	 * List of hosts per template.
-	 *
-	 * This is only for use by scsi_module.c for legacy templates.
-	 * For these access to it is synchronized implicitly by
-	 * module_init/module_exit.
-	 */
-	struct list_head legacy_hosts;
-
 	/*
 	 * Vendor Identifier associated with the host
 	 *
@@ -713,15 +689,6 @@ struct Scsi_Host {
 	/* ldm bits */
 	struct device		shost_gendev, shost_dev;
 
-	/*
-	 * List of hosts per template.
-	 *
-	 * This is only for use by scsi_module.c for legacy templates.
-	 * For these access to it is synchronized implicitly by
-	 * module_init/module_exit.
-	 */
-	struct list_head sht_legacy_list;
-
 	/*
 	 * Points to the transport data (if any) which is allocated
 	 * separately
@@ -922,9 +889,6 @@ static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
 	return shost->prot_guard_type;
 }
 
-/* legacy interfaces */
-extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
-extern void scsi_unregister(struct Scsi_Host *);
 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
 
 #endif /* _SCSI_SCSI_HOST_H */