From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>, Peter Lieven <pl@kamp.de>,
qemu-devel@nongnu.org, ronniesahlberg@gmail.com
Subject: Re: [Qemu-devel] [PATCH 1/2] iscsi: add support for bdrv_co_is_allocated()
Date: Fri, 21 Jun 2013 18:31:09 +0200 [thread overview]
Message-ID: <51C47FCD.2030206@redhat.com> (raw)
In-Reply-To: <20130621110707.GF2986@dhcp-200-207.str.redhat.com>
Il 21/06/2013 13:07, Kevin Wolf ha scritto:
>>> > > Note that you're blocking here. The preferred way would be something
>>> > > involving a yield from the coroutine and a reenter as soon as all
>>> > > requests are done. Maybe a CoRwLock does what you need?
>> > Is there a document how to use it? Or can you help here?
> The idea would be to take a read lock while any request is in flight
> (i.e. qemu_co_rwlock_rdlock() before it's started and
> qemu_co_rwlock_unlock() when it completes), and to take a write lock
> (qemu_co_rwlock_wrlock) for the part of iscsi_co_is_allocated() that
> requires that no other request runs in parallel.
>
You can just send the SCSI command asynchronously and wait for the
result. There is an example in block/qed.c, the same would apply for iscsi.
Paolo
next prev parent reply other threads:[~2013-06-21 16:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-20 18:20 [Qemu-devel] [PATCH 0/2] iscsi: support for is_allocated and inproved has_zero_init Peter Lieven
2013-06-20 18:20 ` [Qemu-devel] [PATCH 1/2] iscsi: add support for bdrv_co_is_allocated() Peter Lieven
2013-06-21 9:18 ` Kevin Wolf
2013-06-21 9:45 ` Peter Lieven
2013-06-21 11:07 ` Kevin Wolf
2013-06-21 11:42 ` Peter Lieven
2013-06-21 13:14 ` Kevin Wolf
2013-06-21 13:23 ` Peter Lieven
2013-06-21 16:31 ` Paolo Bonzini [this message]
2013-06-21 17:06 ` Peter Lieven
2013-06-21 17:13 ` ronnie sahlberg
2013-06-21 17:18 ` Peter Lieven
2013-06-21 16:06 ` ronnie sahlberg
2013-06-21 20:01 ` Paolo Bonzini
2013-06-24 8:13 ` Stefan Hajnoczi
2013-06-24 13:49 ` Paolo Bonzini
2013-06-24 16:11 ` Peter Lieven
2013-06-20 18:20 ` [Qemu-devel] [PATCH 2/2] iscsi: add intelligent has_zero_init check Peter Lieven
2013-06-21 20:00 ` Paolo Bonzini
2013-06-21 20:25 ` Peter Lieven
-- strict thread matches above, loose matches on Subject: below --
2013-06-20 18:08 [Qemu-devel] [PATCH 0/2] iscsi: support for is_allocated and inproved has_zero_init Peter Lieven
2013-06-20 18:08 ` [Qemu-devel] [PATCH 1/2] iscsi: add support for bdrv_co_is_allocated() Peter Lieven
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