All of lore.kernel.org
 help / color / mirror / Atom feed
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



  reply	other threads:[~2016-05-23 17:27 UTC|newest]

Thread overview: 9+ 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-Re5JQEeQqe8AvxtiuMwx3w
2016-05-23 16:02 ` tom.ty89
2016-05-23 17:00 ` Greg KH
     [not found]   ` <20160523170025.GA3309-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2016-05-23 17:23     ` Tom Yan
2016-05-23 17:23       ` Tom Yan
2016-05-23 17:27       ` James Bottomley [this message]
     [not found]         ` <1464024457.2331.10.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-05-23 18:33           ` Tom Yan
2016-05-23 18:33             ` Tom Yan
2016-05-23 19:07             ` James Bottomley

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1464024457.2331.10.camel@HansenPartnership.com \
    --to=james.bottomley@hansenpartnership.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hdegoede@redhat.com \
    --cc=kraxel@redhat.com \
    --cc=linux-scsi@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=stern@rowland.harvard.edu \
    --cc=tom.ty89@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.