kernel-ark/drivers/usb/storage/libusual.c
Christoph Hellwig 04fc8bbcf5 kill DECLARE_MUTEX_LOCKED
DECLARE_MUTEX_LOCKED was used for semaphores used as completions and we've
got rid of them.  Well, except for one in libusual that the maintainer
explicitly wants to keep as semaphore.  So convert that useage to an
explicit sema_init and kill of DECLARE_MUTEX_LOCKED so that new code is
reminded to use a completion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Satyam Sharma" <satyam.sharma@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:47 -07:00

270 lines
6.3 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>
/*
*/
#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 struct semaphore usu_init_notify;
static DECLARE_COMPLETION(usu_end_notify);
static atomic_t total_threads = ATOMIC_INIT(0);
static int usu_probe_thread(void *arg);
/*
* The table.
*/
#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
vendorName, productName,useProtocol, useTransport, \
initFunction, flags) \
{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \
.driver_info = (flags)|(USB_US_TYPE_STOR<<24) }
#define USUAL_DEV(useProto, useTrans, useType) \
{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \
.driver_info = ((useType)<<24) }
struct usb_device_id storage_usb_ids [] = {
# include "unusual_devs.h"
{ } /* Terminating entry */
};
#undef USUAL_DEV
#undef UNUSUAL_DEV
MODULE_DEVICE_TABLE(usb, storage_usb_ids);
EXPORT_SYMBOL_GPL(storage_usb_ids);
/*
* @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_%d", 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 = 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;
/* A completion does not work here because it's counted. */
down(&usu_init_notify);
up(&usu_init_notify);
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);
complete_and_exit(&usu_end_notify, 0);
}
/*
*/
static int __init usb_usual_init(void)
{
int rc;
sema_init(&usu_init_notify, 0);
rc = usb_register(&usu_driver);
up(&usu_init_notify);
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");