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USB: libusual: locking cleanup 

I converted the usu_init_notify semaphore to normal mutex usage, and it
should still prevent the request_module before the init routine is
complete.  Before it acted more like a complete, now the mutex protects two
distinct section from running at the same time.

Signed-off-by: Daniel Walker <dwalker@mvista.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Daniel Walker 2008-02-04 23:57:42 -08:00 committed by Greg Kroah-Hartman
parent d99388aa0a
commit 75c43b6ec6
1 changed files with 6 additions and 8 deletions
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14
drivers/usb/storage/libusual.c
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@ -9,6 +9,7 @@
#include <linux/usb_usual.h>
#include <linux/vmalloc.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
/*
*/
@ -30,7 +31,7 @@ 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 DEFINE_MUTEX(usu_probe_mutex);
static DECLARE_COMPLETION(usu_end_notify);
static atomic_t total_threads = ATOMIC_INIT(0);
@ -178,10 +179,7 @@ static int usu_probe_thread(void *arg)
int rc;
unsigned long flags;
/* A completion does not work here because it's counted. */
down(&usu_init_notify);
up(&usu_init_notify);
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) {
@ -194,6 +192,7 @@ static int usu_probe_thread(void *arg)
}
st->fls &= ~USU_MOD_FL_THREAD;
spin_unlock_irqrestore(&usu_lock, flags);
mutex_unlock(&usu_probe_mutex);
complete_and_exit(&usu_end_notify, 0);
}
@ -204,10 +203,9 @@ static int __init usb_usual_init(void)
{
int rc;
sema_init(&usu_init_notify, 0);
mutex_lock(&usu_probe_mutex);
rc = usb_register(&usu_driver);
up(&usu_init_notify);
mutex_unlock(&usu_probe_mutex);
return rc;
}