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linux-next/drivers/usb/storage/libusual.c
Alan Stern e6e244b6cb usb-storage: prepare for subdriver separation
This patch (as1206) is the first step in converting usb-storage's
subdrivers into separate modules.  It makes the following large-scale
changes:

	Remove a bunch of unnecessary #ifdef's from usb_usual.h.
	Not truly necessary, but it does clean things up.

	Move the USB device-ID table (which is duplicated between
	libusual and usb-storage) into its own source file,
	usual-tables.c, and arrange for this to be linked with
	either libusual or usb-storage according to whether
	USB_LIBUSUAL is configured.

	Add to usual-tables.c a new usb_usual_ignore_device()
	function to detect whether a particular device needs to be
	managed by a subdriver and not by the standard handlers
	in usb-storage.

	Export a whole bunch of functions in usb-storage, renaming
	some of them because their names don't already begin with
	"usb_stor_".  These functions will be needed by the new
	subdriver modules.

	Split usb-storage's probe routine into two functions.
	The subdrivers will call the probe1 routine, then fill in
	their transport and protocol settings, and then call the
	probe2 routine.

	Take the default cases and error checking out of
	get_transport() and get_protocol(), which run during
	probe1, and instead put a check for invalid transport
	or protocol values into the probe2 function.

	Add a new probe routine to be used for standard devices,
	i.e., those that don't need a subdriver.  This new routine
	checks whether the device should be ignored (because it
	should be handled by ub or by a subdriver), and if not,
	calls the probe1 and probe2 functions.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:20:34 -07:00

244 lines
5.7 KiB
C

/*
* libusual
*
* The libusual contains the table of devices common for ub and usb-storage.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb_usual.h>
#include <linux/vmalloc.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
/*
*/
#define USU_MOD_FL_THREAD 1 /* Thread is running */
#define USU_MOD_FL_PRESENT 2 /* The module is loaded */
struct mod_status {
unsigned long fls;
};
static struct mod_status stat[3];
static DEFINE_SPINLOCK(usu_lock);
/*
*/
#define USB_US_DEFAULT_BIAS USB_US_TYPE_STOR
static atomic_t usu_bias = ATOMIC_INIT(USB_US_DEFAULT_BIAS);
#define BIAS_NAME_SIZE (sizeof("usb-storage"))
static const char *bias_names[3] = { "none", "usb-storage", "ub" };
static DEFINE_MUTEX(usu_probe_mutex);
static DECLARE_COMPLETION(usu_end_notify);
static atomic_t total_threads = ATOMIC_INIT(0);
static int usu_probe_thread(void *arg);
/*
* @type: the module type as an integer
*/
void usb_usual_set_present(int type)
{
struct mod_status *st;
unsigned long flags;
if (type <= 0 || type >= 3)
return;
st = &stat[type];
spin_lock_irqsave(&usu_lock, flags);
st->fls |= USU_MOD_FL_PRESENT;
spin_unlock_irqrestore(&usu_lock, flags);
}
EXPORT_SYMBOL_GPL(usb_usual_set_present);
void usb_usual_clear_present(int type)
{
struct mod_status *st;
unsigned long flags;
if (type <= 0 || type >= 3)
return;
st = &stat[type];
spin_lock_irqsave(&usu_lock, flags);
st->fls &= ~USU_MOD_FL_PRESENT;
spin_unlock_irqrestore(&usu_lock, flags);
}
EXPORT_SYMBOL_GPL(usb_usual_clear_present);
/*
* Match the calling driver type against the table.
* Returns: 0 if the device matches.
*/
int usb_usual_check_type(const struct usb_device_id *id, int caller_type)
{
int id_type = USB_US_TYPE(id->driver_info);
if (caller_type <= 0 || caller_type >= 3)
return -EINVAL;
/* Drivers grab fixed assignment devices */
if (id_type == caller_type)
return 0;
/* Drivers grab devices biased to them */
if (id_type == USB_US_TYPE_NONE && caller_type == atomic_read(&usu_bias))
return 0;
return -ENODEV;
}
EXPORT_SYMBOL_GPL(usb_usual_check_type);
/*
*/
static int usu_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
int rc;
unsigned long type;
struct task_struct* task;
unsigned long flags;
type = USB_US_TYPE(id->driver_info);
if (type == 0)
type = atomic_read(&usu_bias);
spin_lock_irqsave(&usu_lock, flags);
if ((stat[type].fls & (USU_MOD_FL_THREAD|USU_MOD_FL_PRESENT)) != 0) {
spin_unlock_irqrestore(&usu_lock, flags);
return -ENXIO;
}
stat[type].fls |= USU_MOD_FL_THREAD;
spin_unlock_irqrestore(&usu_lock, flags);
task = kthread_run(usu_probe_thread, (void*)type, "libusual_%ld", type);
if (IS_ERR(task)) {
rc = PTR_ERR(task);
printk(KERN_WARNING "libusual: "
"Unable to start the thread for %s: %d\n",
bias_names[type], rc);
spin_lock_irqsave(&usu_lock, flags);
stat[type].fls &= ~USU_MOD_FL_THREAD;
spin_unlock_irqrestore(&usu_lock, flags);
return rc; /* Not being -ENXIO causes a message printed */
}
atomic_inc(&total_threads);
return -ENXIO;
}
static void usu_disconnect(struct usb_interface *intf)
{
; /* We should not be here. */
}
static struct usb_driver usu_driver = {
.name = "libusual",
.probe = usu_probe,
.disconnect = usu_disconnect,
.id_table = usb_storage_usb_ids,
};
/*
* A whole new thread for a purpose of request_module seems quite stupid.
* The request_module forks once inside again. However, if we attempt
* to load a storage module from our own modprobe thread, that module
* references our symbols, which cannot be resolved until our module is
* initialized. I wish there was a way to wait for the end of initialization.
* The module notifier reports MODULE_STATE_COMING only.
* So, we wait until module->init ends as the next best thing.
*/
static int usu_probe_thread(void *arg)
{
int type = (unsigned long) arg;
struct mod_status *st = &stat[type];
int rc;
unsigned long flags;
mutex_lock(&usu_probe_mutex);
rc = request_module(bias_names[type]);
spin_lock_irqsave(&usu_lock, flags);
if (rc == 0 && (st->fls & USU_MOD_FL_PRESENT) == 0) {
/*
* This should not happen, but let us keep tabs on it.
*/
printk(KERN_NOTICE "libusual: "
"modprobe for %s succeeded, but module is not present\n",
bias_names[type]);
}
st->fls &= ~USU_MOD_FL_THREAD;
spin_unlock_irqrestore(&usu_lock, flags);
mutex_unlock(&usu_probe_mutex);
complete_and_exit(&usu_end_notify, 0);
}
/*
*/
static int __init usb_usual_init(void)
{
int rc;
mutex_lock(&usu_probe_mutex);
rc = usb_register(&usu_driver);
mutex_unlock(&usu_probe_mutex);
return rc;
}
static void __exit usb_usual_exit(void)
{
/*
* We do not check for any drivers present, because
* they keep us pinned with symbol references.
*/
usb_deregister(&usu_driver);
while (atomic_read(&total_threads) > 0) {
wait_for_completion(&usu_end_notify);
atomic_dec(&total_threads);
}
}
/*
* Validate and accept the bias parameter.
*/
static int usu_set_bias(const char *bias_s, struct kernel_param *kp)
{
int i;
int len;
int bias_n = 0;
len = strlen(bias_s);
if (len == 0)
return -EDOM;
if (bias_s[len-1] == '\n')
--len;
for (i = 1; i < 3; i++) {
if (strncmp(bias_s, bias_names[i], len) == 0) {
bias_n = i;
break;
}
}
if (bias_n == 0)
return -EINVAL;
atomic_set(&usu_bias, bias_n);
return 0;
}
static int usu_get_bias(char *buffer, struct kernel_param *kp)
{
return strlen(strcpy(buffer, bias_names[atomic_read(&usu_bias)]));
}
module_init(usb_usual_init);
module_exit(usb_usual_exit);
module_param_call(bias, usu_set_bias, usu_get_bias, NULL, S_IRUGO|S_IWUSR);
__MODULE_PARM_TYPE(bias, "string");
MODULE_PARM_DESC(bias, "Bias to usb-storage or ub");
MODULE_LICENSE("GPL");