From: Greg Kroah-Hartman Date: Mon, 9 Apr 2007 15:52:31 +0000 (-0400) Subject: USB: remove use of the bus rwsem, as it doesn't really protect anything. X-Git-Tag: v2.6.22-rc1~1119^2~24 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=341487a837c02cbd674d4751061e7d098b0b8e98;p=linux-2.6 USB: remove use of the bus rwsem, as it doesn't really protect anything. The driver core stopped using the rwsem a long time ago, yet the USB core still grabbed the lock, thinking it protected something. This patch removes that useless use. Cc: Alan Stern Cc: Oliver Neukum Cc: David Brownell Cc: linux-usb-devel Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c index aefc798712..6753ca059e 100644 --- a/drivers/usb/core/devices.c +++ b/drivers/usb/core/devices.c @@ -246,7 +246,6 @@ static char *usb_dump_interface_descriptor(char *start, char *end, if (start > end) return start; - down_read(&usb_bus_type.subsys.rwsem); if (iface) { driver_name = (iface->dev.driver ? iface->dev.driver->name @@ -263,7 +262,6 @@ static char *usb_dump_interface_descriptor(char *start, char *end, desc->bInterfaceSubClass, desc->bInterfaceProtocol, driver_name); - up_read(&usb_bus_type.subsys.rwsem); return start; } diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 36e7a843bf..fc3545ddb0 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -421,14 +421,11 @@ static int claimintf(struct dev_state *ps, unsigned int ifnum) if (test_bit(ifnum, &ps->ifclaimed)) return 0; - /* lock against other changes to driver bindings */ - down_write(&usb_bus_type.subsys.rwsem); intf = usb_ifnum_to_if(dev, ifnum); if (!intf) err = -ENOENT; else err = usb_driver_claim_interface(&usbfs_driver, intf, ps); - up_write(&usb_bus_type.subsys.rwsem); if (err == 0) set_bit(ifnum, &ps->ifclaimed); return err; @@ -444,8 +441,6 @@ static int releaseintf(struct dev_state *ps, unsigned int ifnum) if (ifnum >= 8*sizeof(ps->ifclaimed)) return err; dev = ps->dev; - /* lock against other changes to driver bindings */ - down_write(&usb_bus_type.subsys.rwsem); intf = usb_ifnum_to_if(dev, ifnum); if (!intf) err = -ENOENT; @@ -453,7 +448,6 @@ static int releaseintf(struct dev_state *ps, unsigned int ifnum) usb_driver_release_interface(&usbfs_driver, intf); err = 0; } - up_write(&usb_bus_type.subsys.rwsem); return err; } @@ -813,7 +807,6 @@ static int proc_getdriver(struct dev_state *ps, void __user *arg) if (copy_from_user(&gd, arg, sizeof(gd))) return -EFAULT; - down_read(&usb_bus_type.subsys.rwsem); intf = usb_ifnum_to_if(ps->dev, gd.interface); if (!intf || !intf->dev.driver) ret = -ENODATA; @@ -822,7 +815,6 @@ static int proc_getdriver(struct dev_state *ps, void __user *arg) sizeof(gd.driver)); ret = (copy_to_user(arg, &gd, sizeof(gd)) ? -EFAULT : 0); } - up_read(&usb_bus_type.subsys.rwsem); return ret; } @@ -1351,15 +1343,12 @@ static int proc_ioctl(struct dev_state *ps, struct usbdevfs_ioctl *ctl) /* disconnect kernel driver from interface */ case USBDEVFS_DISCONNECT: - - down_write(&usb_bus_type.subsys.rwsem); if (intf->dev.driver) { driver = to_usb_driver(intf->dev.driver); dev_dbg (&intf->dev, "disconnect by usbfs\n"); usb_driver_release_interface(driver, intf); } else retval = -ENODATA; - up_write(&usb_bus_type.subsys.rwsem); break; /* let kernel drivers try to (re)bind to the interface */ @@ -1371,7 +1360,6 @@ static int proc_ioctl(struct dev_state *ps, struct usbdevfs_ioctl *ctl) /* talk directly to the interface's driver */ default: - down_read(&usb_bus_type.subsys.rwsem); if (intf->dev.driver) driver = to_usb_driver(intf->dev.driver); if (driver == NULL || driver->ioctl == NULL) { @@ -1381,7 +1369,6 @@ static int proc_ioctl(struct dev_state *ps, struct usbdevfs_ioctl *ctl) if (retval == -ENOIOCTLCMD) retval = -ENOTTY; } - up_read(&usb_bus_type.subsys.rwsem); } /* cleanup and return */ diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 9e3e943f31..e6dd2b9210 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -287,9 +287,9 @@ static int usb_unbind_interface(struct device *dev) * way to bind to an interface is to return the private data from * the driver's probe() method. * - * Callers must own the device lock and the driver model's usb_bus_type.subsys - * writelock. So driver probe() entries don't need extra locking, - * but other call contexts may need to explicitly claim those locks. + * Callers must own the device lock, so driver probe() entries don't need + * extra locking, but other call contexts may need to explicitly claim that + * lock. */ int usb_driver_claim_interface(struct usb_driver *driver, struct usb_interface *iface, void* priv) @@ -330,9 +330,9 @@ EXPORT_SYMBOL(usb_driver_claim_interface); * also causes the driver disconnect() method to be called. * * This call is synchronous, and may not be used in an interrupt context. - * Callers must own the device lock and the driver model's usb_bus_type.subsys - * writelock. So driver disconnect() entries don't need extra locking, - * but other call contexts may need to explicitly claim those locks. + * Callers must own the device lock, so driver disconnect() entries don't + * need extra locking, but other call contexts may need to explicitly claim + * that lock. */ void usb_driver_release_interface(struct usb_driver *driver, struct usb_interface *iface) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 217a3d6d0a..c359ccb329 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1349,7 +1349,7 @@ static void release_interface(struct device *dev) * * This call is synchronous. The calling context must be able to sleep, * must own the device lock, and must not hold the driver model's USB - * bus rwsem; usb device driver probe() methods cannot use this routine. + * bus mutex; usb device driver probe() methods cannot use this routine. * * Returns zero on success, or else the status code returned by the * underlying call that failed. On successful completion, each interface