diff options
Diffstat (limited to 'drivers/usb/core')
| -rw-r--r-- | drivers/usb/core/file.c | 29 |
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); - - |