Message-ID: <1418628591.4443.0.camel@linux-0dmf.site>
Subject: Re: [V3 PATCH 4/4] scsi:stex.c Add S3/S4 support
From: Oliver Neukum <oneukum@suse.de>
To: Charles Chiou <ch1102chiou@gmail.com>
Cc: JBottomley@parallels.com, linux-kernel@vger.kernel.org,
        linux-scsi@vger.kernel.org, grace.chang@tw.promise.com,
        victor.p@promise.com, ed.lin@promise.com
Date: Mon, 15 Dec 2014 08:29:51 +0100
In-Reply-To: <548E51AB.1030506@gmail.com>
References: <5487A406.8060902@gmail.com>
	 <1418202153.7241.6.camel@linux-0dmf.site> <548E51AB.1030506@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org

On Mon, 2014-12-15 at 11:12 +0800, Charles Chiou wrote:
> 
> On 12/10/2014 05:02 PM, Oliver Neukum wrote:
> > On Wed, 2014-12-10 at 09:38 +0800, Charles Chiou wrote:
> >>   From 91868d4afe10533b8a4496075109e411100217bb Mon Sep 17 00:00:00 2001
> >> From: Charles Chiou <charles.chiou@tw.promise.com>
> >> Date: Fri, 7 Nov 2014 10:15:18 +0800
> >> Subject: [PATCH 4/4] scsi:stex.c Add S3/S4 support
> >>
> >> Add S3/S4 support, add .suspend and .resume function in pci_driver.
> >>
> >> Pegasus need 30~40 seconds to boot up. We don't want to OS wait
> >> in .resume function. Create a thread to handle device boot up.
> >>
> >
> >> +static int stex_resume(struct pci_dev *pdev)
> >> +{
> >> +	struct st_hba *hba = pci_get_drvdata(pdev);
> >> +	struct hba_handshake_workstruct *hswork;
> >> +	int sts;
> >> +
> >> +	hba->mu_status = MU_STATE_STARTING;
> >> +	hswork = kzalloc(sizeof(struct hba_handshake_workstruct), GFP_KERNEL);
> >
> > The system is coming back from sleep. You cannot swap or page out
> > as disks may still be asleep. GFP_KERNEL is automatically changed
> > to GFP_NOIO. It would be nice to outright use GFP_NOIO.
> >
> >> +	INIT_WORK(&hswork->handshake_work, resume_handshake);
> >
> > Memory allocations can fail.
> > I suggest you allocate the memory in suspend(). There you can just
> > return -ENOMEM in the error case.
> >
> >
> Hi Oliver, sorry for the late reply.
> 
> Good point, could we move kzalloc function from suspend to probe and 
> return -ENOMEM when allocation fail? We can avoid to allocate memory
> again and again in suspend/resume cycles.

Yes, that would work.

	Regards
		Oliver


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