From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 14 Apr 2008 12:57:00 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH 2 of 9] Core of mmu notifiers In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: akpm@linux-foundation.org, Nick Piggin , Steve Wise , Peter Zijlstra , linux-mm@kvack.org, Kanoj Sarcar , Roland Dreier , Jack Steiner , linux-kernel@vger.kernel.org, Avi Kivity , kvm-devel@lists.sourceforge.net, Robin Holt , general@lists.openfabrics.org, Hugh Dickins List-ID: On Tue, 8 Apr 2008, Andrea Arcangeli wrote: > + /* > + * Called when nobody can register any more notifier in the mm > + * and after the "mn" notifier has been disarmed already. > + */ > + void (*release)(struct mmu_notifier *mn, > + struct mm_struct *mm); Hmmm... The unregister function does not call this. Guess driver calls unregister function and does release like stuff on its own. > + /* > + * invalidate_range_start() and invalidate_range_end() must be > + * paired. Multiple invalidate_range_start/ends may be nested > + * or called concurrently. > + */ How could they be nested or called concurrently? > +/* > + * mm_users can't go down to zero while mmu_notifier_unregister() > + * runs or it can race with ->release. So a mm_users pin must > + * be taken by the caller (if mm can be different from current->mm). > + */ > +int mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm) > +{ > + struct mm_lock_data *data; > + > + BUG_ON(!atomic_read(&mm->mm_users)); > + > + data = mm_lock(mm); > + if (unlikely(IS_ERR(data))) > + return PTR_ERR(data); > + hlist_del(&mn->hlist); > + mm_unlock(mm, data); > + return 0; Hmmm.. Ok, the user of the notifier does not get notified that it was unregistered. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org