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From: Paolo Bonzini <pbonzini@redhat.com>
To: Maxim Levitsky <mlevitsk@redhat.com>, qemu-devel@nongnu.org
Cc: Stefan Hajnoczi <stefanha@gmail.com>, stefanha@redhat.com
Subject: Re: [PATCH 08/10] scsi/scsi_bus: Add scsi_device_get
Date: Wed, 30 Sep 2020 19:46:32 +0200	[thread overview]
Message-ID: <67859d7f-5293-a11e-add3-f93893dfa7af@redhat.com> (raw)
In-Reply-To: <0d124b6991e607e496da4afa39027320e617aa0e.camel@redhat.com>

On 30/09/20 16:32, Maxim Levitsky wrote:
>> 	Compared to Maxim's patch, I am avoiding the extra argument
>> 	to do_scsi_device_find by moving the RCU_READ_LOCK_GUARD()
>> 	out of do_scsi_device_find itself.
> Which is a good idea, although my mindset was like, I got a device,
> lets just grab a ref to it before it disappears and then do
> whatever I want.

Understood, but "I got a device, I know I'm under RCU so it can't
disappear" is more efficient and just as common.  This also explains the
difference in patch 7.

Paolo



  reply	other threads:[~2020-09-30 17:48 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 17:25 [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread Paolo Bonzini
2020-09-25 17:25 ` [PATCH 01/10] qdev: add "check if address free" callback for buses Paolo Bonzini
2020-09-28  9:30   ` Stefan Hajnoczi
2020-09-30 17:48     ` Paolo Bonzini
2020-09-30 14:27   ` Maxim Levitsky
2020-09-30 23:37     ` Paolo Bonzini
2020-09-25 17:25 ` [PATCH 02/10] scsi: switch to bus->check_address Paolo Bonzini
2020-09-28  9:43   ` Stefan Hajnoczi
2020-09-30 14:28   ` Maxim Levitsky
2020-09-25 17:25 ` [PATCH 03/10] scsi/scsi_bus: switch search direction in scsi_device_find Paolo Bonzini
2020-09-25 17:25 ` [PATCH 04/10] device_core: use drain_call_rcu in in hmp_device_del/qmp_device_add Paolo Bonzini
2020-09-25 17:25 ` [PATCH 05/10] device-core: use RCU for list of children of a bus Paolo Bonzini
2020-09-30 14:29   ` Maxim Levitsky
2020-09-25 17:26 ` [PATCH 06/10] device-core: use atomic_set on .realized property Paolo Bonzini
2020-09-30 14:31   ` Maxim Levitsky
2020-09-30 17:44     ` Paolo Bonzini
2020-09-30 18:03       ` Maxim Levitsky
2020-09-25 17:26 ` [PATCH 07/10] scsi/scsi-bus: scsi_device_find: don't return unrealized devices Paolo Bonzini
2020-09-30 14:32   ` Maxim Levitsky
2020-09-25 17:26 ` [PATCH 08/10] scsi/scsi_bus: Add scsi_device_get Paolo Bonzini
2020-09-30 14:32   ` Maxim Levitsky
2020-09-30 17:46     ` Paolo Bonzini [this message]
2020-09-30 18:04       ` Maxim Levitsky
2020-09-25 17:26 ` [PATCH 09/10] virtio-scsi: use scsi_device_get Paolo Bonzini
2020-09-25 17:26 ` [PATCH 10/10] scsi/scsi_bus: fix races in REPORT LUNS Paolo Bonzini
2020-09-30 14:34   ` Maxim Levitsky
2020-09-25 19:26 ` [PATCH 00/10] Fix scsi devices plug/unplug races w.r.t virtio-scsi iothread no-reply
2020-09-25 22:52 ` no-reply
2020-09-26  0:28 ` no-reply
2020-09-26  0:44 ` no-reply
2020-09-26  1:05 ` no-reply

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