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path: root/drivers/usb/core
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Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/file.c29
1 files changed, 13 insertions, 16 deletions
diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
index 01c857ac27a..5d860bc9b42 100644
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -16,15 +16,15 @@
*/
#include <linux/module.h>
-#include <linux/spinlock.h>
#include <linux/errno.h>
+#include <linux/rwsem.h>
#include <linux/usb.h>
#include "usb.h"
#define MAX_USB_MINORS 256
static const struct file_operations *usb_minors[MAX_USB_MINORS];
-static DEFINE_SPINLOCK(minor_lock);
+static DECLARE_RWSEM(minor_rwsem);
static int usb_open(struct inode * inode, struct file * file)
{
@@ -33,14 +33,11 @@ static int usb_open(struct inode * inode, struct file * file)
int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL;
- spin_lock (&minor_lock);
+ down_read(&minor_rwsem);
c = usb_minors[minor];
- if (!c || !(new_fops = fops_get(c))) {
- spin_unlock(&minor_lock);
- return err;
- }
- spin_unlock(&minor_lock);
+ if (!c || !(new_fops = fops_get(c)))
+ goto done;
old_fops = file->f_op;
file->f_op = new_fops;
@@ -52,6 +49,8 @@ static int usb_open(struct inode * inode, struct file * file)
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
+ done:
+ up_read(&minor_rwsem);
return err;
}
@@ -166,7 +165,7 @@ int usb_register_dev(struct usb_interface *intf,
if (class_driver->fops == NULL)
goto exit;
- spin_lock (&minor_lock);
+ down_write(&minor_rwsem);
for (minor = minor_base; minor < MAX_USB_MINORS; ++minor) {
if (usb_minors[minor])
continue;
@@ -176,7 +175,7 @@ int usb_register_dev(struct usb_interface *intf,
retval = 0;
break;
}
- spin_unlock (&minor_lock);
+ up_write(&minor_rwsem);
if (retval)
goto exit;
@@ -197,9 +196,9 @@ int usb_register_dev(struct usb_interface *intf,
intf->usb_dev = device_create(usb_class->class, &intf->dev,
MKDEV(USB_MAJOR, minor), "%s", temp);
if (IS_ERR(intf->usb_dev)) {
- spin_lock (&minor_lock);
+ down_write(&minor_rwsem);
usb_minors[intf->minor] = NULL;
- spin_unlock (&minor_lock);
+ up_write(&minor_rwsem);
retval = PTR_ERR(intf->usb_dev);
}
exit:
@@ -236,9 +235,9 @@ void usb_deregister_dev(struct usb_interface *intf,
dbg ("removing %d minor", intf->minor);
- spin_lock (&minor_lock);
+ down_write(&minor_rwsem);
usb_minors[intf->minor] = NULL;
- spin_unlock (&minor_lock);
+ up_write(&minor_rwsem);
snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
@@ -247,5 +246,3 @@ void usb_deregister_dev(struct usb_interface *intf,
destroy_usb_class();
}
EXPORT_SYMBOL(usb_deregister_dev);
-
-