From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Tom Yan <tom.ty89@gmail.com>, Greg KH <gregkh@linuxfoundation.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>,
Alan Stern <stern@rowland.harvard.edu>,
linux-usb@vger.kernel.org, linux-scsi@vger.kernel.org,
stable@vger.kernel.org, hdegoede@redhat.com
Subject: Re: [PATCH 1/1] uas: leave can_queue as MAX_CMNDS if device reports larger qdepth
Date: Mon, 23 May 2016 10:27:37 -0700 [thread overview]
Message-ID: <1464024457.2331.10.camel@HansenPartnership.com> (raw)
In-Reply-To: <CAGnHSE=Gt3XP9g5KpEyYUWGdw-kwqGDKpBQzd5qagxrjeHsxRA@mail.gmail.com>
On Tue, 2016-05-24 at 01:23 +0800, Tom Yan wrote:
> Nothing wrong. It's just .can_queue = MAX_CMNDS in the host template
> is no longer neceesary, since with his patch, uas will set can_queue
> again later (to devinfo->qdepth - 2).
>
> Originally I thought .can_queue = MAX_CMNDS can hence be removed; but
> after a second thought, I think it might probably be better if we
> leave it there and make use of it, in case certain device somehow
> inapproriately reports an enormous qdepth (i.e. larger than
> MAX_CMNDS). (According to the commit message of 55ff8cfbc4e1 ("USB:
> uas: Reduce can_queue to MAX_CMNDS"), "The uas driver can never queue
> more then MAX_CMNDS...")
OK, so try this as an exercise: Why would this not be the right thing
to do after the host is prepared: It has to do with the streams
resources the driver has already created.
James
next prev parent reply other threads:[~2016-05-23 17:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 16:02 [PATCH 1/1] uas: leave can_queue as MAX_CMNDS if device reports larger qdepth tom.ty89
2016-05-23 17:00 ` Greg KH
2016-05-23 17:23 ` Tom Yan
2016-05-23 17:27 ` James Bottomley [this message]
2016-05-23 18:33 ` Tom Yan
2016-05-23 19:07 ` James Bottomley
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