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b=okwIfj4PXWp0FtNFyJm/O1vTiBK5ex1H0qxKdjJfCdQ0DzVeAOTgDrFUNmjJue46M 6js9z4Gi942KjxxZSuJ9Q4f21WZiH9CxUp0BIgVOQXvbfQuuzVX2M/HMTwts5lYRs6 EUwQl1dKuj+xxeHpafmXiwprFo2N3mgP0SlRFbNJtmKnWY4BEyvE1SW3xI4QNt+yhn SfzRu3aXhvv8EMuhN12AWhHidZn5I9Q+8rC3SSaA88HYWBdjbumKPwG7YrF/y2aVBY NuF3jWEpTTHkdiLgdo+TyS3TSN561vygzK9LTRYP6Lo71JmWTaj5sSgkmUBHeo6/XG c+70RXX/zDSwQ== From: Pratyush Yadav To: Pasha Tatashin Cc: rppt@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dmatlack@google.com, pratyush@kernel.org, skhawaja@google.com Subject: Re: [PATCH v3 07/10] liveupdate: Auto unregister FLBs on file handler unregistration In-Reply-To: <20260327033335.696621-8-pasha.tatashin@soleen.com> (Pasha Tatashin's message of "Fri, 27 Mar 2026 03:33:31 +0000") References: <20260327033335.696621-1-pasha.tatashin@soleen.com> <20260327033335.696621-8-pasha.tatashin@soleen.com> Date: Fri, 03 Apr 2026 10:17:14 +0000 Message-ID: <2vxzika8e4b9.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 3BF18C000D X-Stat-Signature: xk7k6wpj56g1rimkkiytrpmgk7w7bm43 X-HE-Tag: 1775211439-836746 X-HE-Meta: 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 NGoqMfGW E015Q9RNlEusiKYir2LmJojgxHyK7fIDO9HB31I08g5yxD4iB5QNlFl7nXkYzFZz5+BsVvDhPKx5roFM0/xS+yddkmljBH7CdKwJBkdZVl7hspFxaI6BKLT7KgU8aAjKCeV2KMQ+n001MjiSumN4p+H9WB/Mtv7eo1iZZlMkVqQjVn/+wtY1nTLei1DiCS/vIRTKiYV23sHQ28HkjyDmtPZa8n5lbRLrWqmG19+/TqqaGEp2VUdFqAR1USg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 27 2026, Pasha Tatashin wrote: > To ensure that unregistration is always successful and doesn't leave > dangling resources, introduce auto-unregistration of FLBs: when a file > handler is unregistered, all FLBs associated with it are automatically > unregistered. > > Introduce a new helper luo_flb_unregister_all() which unregisters all > FLBs linked to the given file handler. > > Signed-off-by: Pasha Tatashin > --- > kernel/liveupdate/luo_file.c | 14 +----- > kernel/liveupdate/luo_flb.c | 84 ++++++++++++++++++++++---------- > kernel/liveupdate/luo_internal.h | 1 + > 3 files changed, 60 insertions(+), 39 deletions(-) > > diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c > index 439177c10723..80f4e3b796a6 100644 > --- a/kernel/liveupdate/luo_file.c > +++ b/kernel/liveupdate/luo_file.c > @@ -895,26 +895,16 @@ int liveupdate_register_file_handler(struct liveupdate_file_handler *fh) > */ > int liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh) > { > - int err = -EBUSY; > - > if (!liveupdate_enabled()) > return -EOPNOTSUPP; > > liveupdate_test_unregister(fh); > > - down_write(&luo_register_rwlock); > - if (!list_empty(&ACCESS_PRIVATE(fh, flb_list))) > - goto err_unlock; > - > + guard(rwsem_write)(&luo_register_rwlock); > + luo_flb_unregister_all(fh); > list_del(&ACCESS_PRIVATE(fh, list)); > - up_write(&luo_register_rwlock); > > module_put(fh->ops->owner); > > return 0; > - > -err_unlock: > - up_write(&luo_register_rwlock); > - liveupdate_test_register(fh); > - return err; > } > diff --git a/kernel/liveupdate/luo_flb.c b/kernel/liveupdate/luo_flb.c > index ac6fa5b34b43..f8348138de70 100644 > --- a/kernel/liveupdate/luo_flb.c > +++ b/kernel/liveupdate/luo_flb.c > @@ -335,6 +335,62 @@ void luo_flb_file_finish(struct liveupdate_file_handler *fh) > luo_flb_file_finish_one(iter->flb); > } > > +static void luo_flb_unregister_one(struct liveupdate_file_handler *fh, > + struct liveupdate_flb *flb) > +{ > + struct luo_flb_private *private = luo_flb_get_private(flb); > + struct list_head *flb_list = &ACCESS_PRIVATE(fh, flb_list); > + struct luo_flb_link *iter; > + bool found = false; > + > + /* Find and remove the link from the file handler's list */ Nit: it would be nice to have a lockdep_assert_held_write() here to clearly show that the luo_register_rwlock must be held when modifying the list. I know that luo_flb_unregister_all() already has one, but in case we refactor later or add another caller. Other than this, Reviewed-by: Pratyush Yadav (Google) > + list_for_each_entry(iter, flb_list, list) { > + if (iter->flb == flb) { > + list_del(&iter->list); > + kfree(iter); > + found = true; > + break; > + } > + } > + [...] -- Regards, Pratyush Yadav