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Thu, 29 Mar 2018 04:53:08 -0400 Received: from verein.lst.de ([213.95.11.211]:49386 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750946AbeC2IxH (ORCPT ); Thu, 29 Mar 2018 04:53:07 -0400 Date: Thu, 29 Mar 2018 10:53:05 +0200 From: Christoph Hellwig To: Al Viro Cc: Christoph Hellwig , 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 07/30] aio: add delayed cancel support Message-ID: <20180329085305.GA22215@lst.de> References: <20180328072926.17131-1-hch@lst.de> <20180328072926.17131-8-hch@lst.de> <20180328163526.GV30522@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180328163526.GV30522@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, Mar 28, 2018 at 05:35:26PM +0100, Al Viro wrote: > > ret = vfs_fsync(req->file, req->datasync); > > - fput(req->file); > > - aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0); > > + if (aio_complete(iocb, ret, 0, 0)) > > + fput(file); > > IDGI. > 1) can aio_complete() ever return false here? It won't. But sometimes checking the return value and sometimes not seems like a bad pattern. > 2) do we ever have aio_kiocb that would not have an associated > struct file * that needs to be dropped on successful aio_complete()? AFAICS, > rw, fsync and poll variants all have one, and I'm not sure what kind of > async IO *could* be done without an opened file. All have a file assoiated at least right now. As mentioned last time finding a struct to pass that file would be rather annoying, so we'd either have to pass it explicitly, or do something nasty like duplicating the pointer in the aio_kiocb in addition to struct kiocb. Which might not be that bad after all, as it would only bloat the aio_kiocb and not struct kiocb used on stack all over.