From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51078) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dk99i-0007sT-RU for qemu-devel@nongnu.org; Tue, 22 Aug 2017 09:23:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dk99i-0000JZ-3c for qemu-devel@nongnu.org; Tue, 22 Aug 2017 09:23:42 -0400 References: <20170822125113.5025-1-stefanha@redhat.com> From: Paolo Bonzini Message-ID: <8b6f5029-44e8-c14b-6730-6db69ce73f7e@redhat.com> Date: Tue, 22 Aug 2017 15:23:32 +0200 MIME-Version: 1.0 In-Reply-To: <20170822125113.5025-1-stefanha@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] nbd-client: avoid spurious qio_channel_yield() re-entry List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: "Dr. David Alan Gilbert" , qemu-block@nongnu.org, Eric Blake On 22/08/2017 14:51, Stefan Hajnoczi wrote: > This should fix the issue that Dave is seeing but I'm concerned that > there are more problems in nbd-client.c. We don't have good > abstractions for writing coroutine socket I/O code. Something like Go's > channels would avoid manual low-level coroutine calls. There is > currently no way to cancel qio_channel_yield() so requests doing I/O may > remain in-flight indefinitely and nbd-client.c doesn't join them... The idea was that shutdown(2) would force them to reenter... Paolo