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>
diff --git a/drivers/usb/storage/libusual.c b/drivers/usb/storage/libusual.c
index 55b9520..a28d491 100644
--- a/drivers/usb/storage/libusual.c
+++ b/drivers/usb/storage/libusual.c
@@ -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 @@
#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 @@
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 @@
}
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 @@
{
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;
}
