From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:38308 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934168AbeCTAVM (ORCPT ); Mon, 19 Mar 2018 20:21:12 -0400 Date: Mon, 19 Mar 2018 17:21:03 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: viro@zeniv.linux.org.uk, Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/36] aio: sanitize ki_list handling Message-ID: <20180320002103.GB7282@magnolia> References: <20180305212743.16664-1-hch@lst.de> <20180305212743.16664-5-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180305212743.16664-5-hch@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, Mar 05, 2018 at 01:27:11PM -0800, Christoph Hellwig wrote: > Instead of handcoded non-null checks always initialize ki_list to an > empty list and use list_empty / list_empty_careful on it. While we're > at it also error out on a double call to kiocb_set_cancel_fn instead > of ignoring it. > > Signed-off-by: Christoph Hellwig > Acked-by: Jeff Moyer Reviewed-by: Darrick J. Wong --D > --- > fs/aio.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index 6295fc00f104..c32c315f05b5 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -555,13 +555,12 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) > struct kioctx *ctx = req->ki_ctx; > unsigned long flags; > > - spin_lock_irqsave(&ctx->ctx_lock, flags); > - > - if (!req->ki_list.next) > - list_add(&req->ki_list, &ctx->active_reqs); > + if (WARN_ON_ONCE(!list_empty(&req->ki_list))) > + return; > > + spin_lock_irqsave(&ctx->ctx_lock, flags); > + list_add_tail(&req->ki_list, &ctx->active_reqs); > req->ki_cancel = cancel; > - > spin_unlock_irqrestore(&ctx->ctx_lock, flags); > } > EXPORT_SYMBOL(kiocb_set_cancel_fn); > @@ -1034,7 +1033,7 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) > goto out_put; > > percpu_ref_get(&ctx->reqs); > - > + INIT_LIST_HEAD(&req->ki_list); > req->ki_ctx = ctx; > return req; > out_put: > @@ -1080,7 +1079,7 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2) > unsigned tail, pos, head; > unsigned long flags; > > - if (iocb->ki_list.next) { > + if (!list_empty_careful(iocb->ki_list.next)) { > unsigned long flags; > > spin_lock_irqsave(&ctx->ctx_lock, flags); > -- > 2.14.2 >