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From: Ming Lei <ming.lei@redhat.com>
To: John Garry <john.garry@huawei.com>
Cc: jejb@linux.ibm.com, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
	kashyap.desai@broadcom.com, dgilbert@interlog.com
Subject: Re: [PATCH] scsi: core: Cap initial sdev queue depth at shost.can_queue
Date: Tue, 20 Apr 2021 08:02:40 +0800	[thread overview]
Message-ID: <YH4aIECa/J/1uS5S@T590> (raw)
In-Reply-To: <1618848384-204144-1-git-send-email-john.garry@huawei.com>

On Tue, Apr 20, 2021 at 12:06:24AM +0800, John Garry wrote:
> Function sdev_store_queue_depth() enforces that the sdev queue depth cannot
> exceed shost.can_queue.
> 
> However, the LLDD may still set cmd_per_lun > can_queue, which leads to an
> initial sdev queue depth greater than can_queue.
> 
> Stop this happened by capping initial sdev queue depth at can_queue.
> 
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
> Topic originally discussed at:
> https://lore.kernel.org/linux-scsi/85dec8eb-8eab-c7d6-b0fb-5622747c5499@interlog.com/T/#m5663d0cac657d843b93d0c9a2374f98fc04384b9
> 
> Last idea there was to error/warn in scsi_add_host() for cmd_per_lun >

No, that isn't my suggestion.

> can_queue. However, such a shost driver could still configure the sdev
> queue depth to be sound value at .slave_configure callback, so now thinking
> the orig patch better.

As I mentioned last time, why can't we fix ->cmd_per_lun in
scsi_add_host() using .can_queue?

-- 
Ming


  reply	other threads:[~2021-04-20  0:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-19 16:06 [PATCH] scsi: core: Cap initial sdev queue depth at shost.can_queue John Garry
2021-04-20  0:02 ` Ming Lei [this message]
2021-04-20  8:14   ` John Garry
2021-04-22  1:38     ` Ming Lei
2021-04-22 16:35       ` John Garry
2021-04-23  1:54         ` Ming Lei

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