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From: Bart Van Assche <bvanassche@acm.org>
To: Mike Christie <michael.christie@oracle.com>,
	martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	target-devel@vger.kernel.org, mst@redhat.com,
	jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 4/8] vhost scsi: fix cmd completion race
Date: Mon, 21 Sep 2020 19:51:16 -0700	[thread overview]
Message-ID: <89c3be36-c03f-c8a0-c4dc-d46d57de86ae@acm.org> (raw)
In-Reply-To: <cf8e5b11-dfd2-4570-1dab-25486c591dde@acm.org>

On 2020-09-21 19:48, Bart Van Assche wrote:
> On 2020-09-21 11:23, Mike Christie wrote:
>> We might not do the final se_cmd put from vhost_scsi_complete_cmd_work.
>> If the last put happens a little later then we could race where
>> vhost_scsi_complete_cmd_work does vhost_signal, the guest runs and sends
>> more IO, and vhost_scsi_handle_vq runs but does not find any free cmds.
>>
>> This patch has us delay completing the cmd until the last lio core ref
>> is dropped. We then know that once we signal to the guest that the cmd
>> is completed that if it queues a new command it will find a free cmd.
> 
> It seems weird to me to see a reference to LIO in the description of a
> vhost patch? Since this driver supports more backends than LIO, shouldn't
> the patch description be made more generic?

Please ignore the above comment.

Bart.

  reply	other threads:[~2020-09-22  2:51 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-21 18:23 [PATCH 0/8] vhost scsi: fixes and cleanups Mike Christie
2020-09-21 18:23 ` [PATCH 1/8] vhost vdpa: fix vhost_vdpa_open error handling Mike Christie
2020-09-22  1:58   ` Jason Wang
2020-09-21 18:23 ` [PATCH 2/8] vhost: add helper to check if a vq has been setup Mike Christie
2020-09-22  2:02   ` Jason Wang
2020-09-23 19:12     ` Mike Christie
2020-09-24  7:22       ` Jason Wang
2020-09-22  2:45   ` Bart Van Assche
2020-09-22 15:34     ` Michael Christie
2020-09-21 18:23 ` [PATCH 3/8] vhost scsi: alloc cmds per vq instead of session Mike Christie
2020-09-22  1:32   ` kernel test robot
2020-09-23  7:53   ` Dan Carpenter
2020-09-24  6:22   ` Michael S. Tsirkin
2020-09-24 15:31     ` Michael Christie
2020-09-21 18:23 ` [PATCH 4/8] vhost scsi: fix cmd completion race Mike Christie
2020-09-22  2:48   ` Bart Van Assche
2020-09-22  2:51     ` Bart Van Assche [this message]
2020-09-21 18:23 ` [PATCH 5/8] vhost scsi: add lun parser helper Mike Christie
2020-09-23 10:23   ` Paolo Bonzini
2020-09-21 18:23 ` [PATCH 6/8] vhost scsi: Add support for LUN resets Mike Christie
2020-09-21 18:23 ` [PATCH 7/8] vhost: remove work arg from vhost_work_flush Mike Christie
2020-09-22  2:01   ` Jason Wang
2020-09-21 18:23 ` [PATCH 8/8] vhost scsi: remove extra flushes Mike Christie

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