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Commit 75c43b6e authored by Daniel Walker's avatar Daniel Walker Committed by Greg Kroah-Hartman
Browse files

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: default avatarDaniel Walker <dwalker@mvista.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d99388aa

drivers/usb/storage/libusual.c

+6 −8
Original line number Diff line number Diff line
@@ -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;

}