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From: Hanna Czenczek <hreitz@redhat.com>
To: Michael Tokarev <mjt@tls.msk.ru>, qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, qemu-stable@nongnu.org,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <fam@euphon.net>
Subject: Re: [PATCH 0/2] block: Allow concurrent BB context changes
Date: Fri, 9 Feb 2024 17:51:18 +0100	[thread overview]
Message-ID: <272941d6-fb76-4c5c-968e-d441c7957646@redhat.com> (raw)
In-Reply-To: <9bc07eef-da55-4ebf-a4ee-1d55eb6fd921@tls.msk.ru>

On 09.02.24 15:08, Michael Tokarev wrote:
> 02.02.2024 17:47, Hanna Czenczek :
>> Hi,
>>
>> Without the AioContext lock, a BB's context may kind of change at any
>> time (unless it has a root node, and I/O requests are pending). That
>> also means that its own context (BlockBackend.ctx) and that of its root
>> node can differ sometimes (while the context is being changed).
>
> How relevant this is for -stable (8.2 at least) which does not have
> "scsi: eliminate AioContext lock" patchset, and in particular,:
> v8.2.0-124-geaad0fe260 "scsi: only access SCSIDevice->requests from
> one thread"?
>
> The issue first patch "block-backend: Allow concurrent context changes"
> fixes (RHEL-19381) seems to be for 8.1.something, so it exists in 8.2
> too, and this particular fix applies to 8.2.
>
> But with other changes around all this, I'm a bit lost as of what should
> be done on stable.  Not even thinking about 7.2 here :)

Ah, sorry, yes.  Since we do still have the AioContext lock, this series 
won’t be necessary in -stable.  Sorry for the noise!

Hanna



  reply	other threads:[~2024-02-09 16:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-02 14:47 [PATCH 0/2] block: Allow concurrent BB context changes Hanna Czenczek
2024-02-02 14:47 ` [PATCH 1/2] block-backend: Allow concurrent " Hanna Czenczek
2024-02-06 16:55   ` Stefan Hajnoczi
2024-02-02 14:47 ` [PATCH 2/2] scsi: Await request purging Hanna Czenczek
2024-02-06 16:56   ` Stefan Hajnoczi
2024-02-06 16:53 ` [PATCH 0/2] block: Allow concurrent BB context changes Stefan Hajnoczi
2024-02-07  9:35   ` Hanna Czenczek
2024-02-08 21:15     ` Stefan Hajnoczi
2024-02-07 13:55 ` Kevin Wolf
2024-02-09 14:08 ` Michael Tokarev
2024-02-09 16:51   ` Hanna Czenczek [this message]
2024-02-10  8:46     ` Michael Tokarev
2024-02-12  8:52       ` Hanna Czenczek

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