Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752784AbXJWEBq (ORCPT ); Tue, 23 Oct 2007 00:01:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750852AbXJWEBj (ORCPT ); Tue, 23 Oct 2007 00:01:39 -0400 Received: from netrider.rowland.org ([192.131.102.5]:4514 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750815AbXJWEBi (ORCPT ); Tue, 23 Oct 2007 00:01:38 -0400 Date: Tue, 23 Oct 2007 00:01:37 -0400 (EDT) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Arnd Bergmann cc: gregkh@suse.de, , , , Peter Zijlstra , Ingo Molnar , LKML , , Thomas Gleixner , , , Andrew Morton , Linus Torvalds , Subject: Re: [linux-usb-devel] USB HCD: avoid duplicate local_irq_disable() In-Reply-To: <200710230328.33915.arnd@arndb.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1434 Lines: 44 On Tue, 23 Oct 2007, Arnd Bergmann wrote: > usb_hcd_flush_endpoint() has a retry loop that starts with a spin_lock_irq(), > but only gives up the spinlock, not the irq_disable before jumping to the > rescan label. > > Split the spin_lock_irq into the retryable part and the local_irq_disable() > that is only done once as a micro-optimization and slight cleanup. I agree with your sentiment, but it would be better to solve this problem without using local_irq_disable(). The patch below does this. --- Signed-off-by: Alan Stern Index: usb-2.6/drivers/usb/core/hcd.c =================================================================== --- usb-2.6.orig/drivers/usb/core/hcd.c +++ usb-2.6/drivers/usb/core/hcd.c @@ -1312,8 +1312,8 @@ void usb_hcd_flush_endpoint(struct usb_d hcd = bus_to_hcd(udev->bus); /* No more submits can occur */ -rescan: spin_lock_irq(&hcd_urb_list_lock); +rescan: list_for_each_entry (urb, &ep->urb_list, urb_list) { int is_in; @@ -1346,6 +1346,7 @@ rescan: usb_put_urb (urb); /* list contents may have changed */ + spin_lock(&hcd_urb_list_lock); goto rescan; } spin_unlock_irq(&hcd_urb_list_lock); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/