Re: reeze while write on external usb 3.0 hard disk [Bug 204095]

From: Alan Stern <stern@rowland.harvard.edu>
To: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	USB list <linux-usb@vger.kernel.org>,
	<linux-block@vger.kernel.org>,
	Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: reeze while write on external usb 3.0 hard disk [Bug 204095]
Date: Thu, 17 Oct 2019 15:23:34 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1910171522200.18407-100000@netrider.rowland.org> (raw)
In-Reply-To: <20191017175306.GA3014@lazy.lzy>

On Thu, 17 Oct 2019, Piergiorgio Sartor wrote:

> > Here is one more thing you can try.  I have no idea whether it will 
> > make any difference, but the Changelog entry for the patch you 
> > identified suggests that it might help.
> > 
> > Alan Stern
> > 
> > 
> > 
> > Index: usb-devel/drivers/usb/storage/scsiglue.c
> > ===================================================================
> > --- usb-devel.orig/drivers/usb/storage/scsiglue.c
> > +++ usb-devel/drivers/usb/storage/scsiglue.c
> > @@ -68,7 +68,6 @@ static const char* host_info(struct Scsi
> >  static int slave_alloc (struct scsi_device *sdev)
> >  {
> >  	struct us_data *us = host_to_us(sdev->host);
> > -	int maxp;
> >  
> >  	/*
> >  	 * Set the INQUIRY transfer length to 36.  We don't use any of
> > @@ -78,15 +77,6 @@ static int slave_alloc (struct scsi_devi
> >  	sdev->inquiry_len = 36;
> >  
> >  	/*
> > -	 * USB has unusual scatter-gather requirements: the length of each
> > -	 * scatterlist element except the last must be divisible by the
> > -	 * Bulk maxpacket value.  Fortunately this value is always a
> > -	 * power of 2.  Inform the block layer about this requirement.
> > -	 */
> > -	maxp = usb_maxpacket(us->pusb_dev, us->recv_bulk_pipe, 0);
> > -	blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
> > -
> > -	/*
> >  	 * Some host controllers may have alignment requirements.
> >  	 * We'll play it safe by requiring 512-byte alignment always.
> >  	 */
> 
> Hi,
> 
> I tested the patch.
> 
> Assumming I did everything properly, add patch,
> test, issue not showing up, remove patch, re-test,
> issue present.
> 
> It seems this patch you provide solves the issue.
> 
> Thanks a lot for the support and the solution.
> 
> I guess now this patch will be integrated into
> mainline sometimes.
> Please let me know, in this thread or directly, in
> which kernel it will be available.

I'm busy for the next few days, but I will submit the patch next week.

> Thanks again, it would be for me impossible to
> solve without your support,

You're welcome.

Alan Stern