All of lore.kernel.org
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: qemu-devel@nongnu.org,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	qemu-block@nongnu.org, Eric Blake <eblake@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] nbd-client: avoid spurious qio_channel_yield() re-entry
Date: Wed, 23 Aug 2017 18:15:35 +0200	[thread overview]
Message-ID: <1c4ee8ba-c179-0a8c-0fe3-ffa1be38e0a5@redhat.com> (raw)
In-Reply-To: <20170823144553.GE16760@stefanha-x1.localdomain>

On 23/08/2017 16:45, Stefan Hajnoczi wrote:
> That depends on the BDRV_POLL_WHILE() allowing all request coroutines to
> terminate before we call nbd_client_detach_aio_context():
> 
>     qio_channel_shutdown(client->ioc,
>                          QIO_CHANNEL_SHUTDOWN_BOTH,
>                          NULL);
>     BDRV_POLL_WHILE(bs, client->read_reply_co);
> 
>     nbd_client_detach_aio_context(bs);
> 
> I'm not sure we have any guarantee that request coroutines will have
> terminated.

Ok, I see my confusion, it's only because of the "receiving" flag which
actually means "waiting for reply".  Your patch is okay.

Paolo

> Once nbd_client_detach_aio_context() is called
> ioc->read_coroutine/write_coroutine are set to NULL.  At that point any
> remaining coroutine doing I/O on ioc will be in trouble.

  reply	other threads:[~2017-08-23 16:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-22 12:51 [Qemu-devel] [PATCH] nbd-client: avoid spurious qio_channel_yield() re-entry Stefan Hajnoczi
2017-08-22 13:23 ` Paolo Bonzini
2017-08-23 14:45   ` Stefan Hajnoczi
2017-08-23 16:15     ` Paolo Bonzini [this message]
2017-08-22 16:18 ` Dr. David Alan Gilbert
2017-08-23 14:20 ` Eric Blake
2017-08-23 14:26   ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2017-08-23 14:51 ` [Qemu-devel] " Eric Blake
2017-08-23 16:17   ` Paolo Bonzini
2017-08-23 15:31 ` Vladimir Sementsov-Ogievskiy
2017-08-23 15:45 ` Eric Blake

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1c4ee8ba-c179-0a8c-0fe3-ffa1be38e0a5@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=dgilbert@redhat.com \
    --cc=eblake@redhat.com \
    --cc=qemu-block@nongnu.org \
    --cc=qemu-devel@nongnu.org \
    --cc=stefanha@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.