linux-kernel - Re: [PATCH] ARM: at91: pm: add missing put_device() call in at91_pm_sram

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Message-ID: <20200717225542.GZ3428@piout.net>
Date:   Sat, 18 Jul 2020 00:55:42 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     "yukuai (C)" <yukuai3@...wei.com>
Cc:     linux@...linux.org.uk, nicolas.ferre@...rochip.com,
        ludovic.desroches@...rochip.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        yi.zhang@...wei.com
Subject: Re: [PATCH] ARM: at91: pm: add missing put_device() call in
 at91_pm_sram_init()

On 03/07/2020 09:15:20+0800, yukuai (C) wrote:
> 
> On 2020/7/3 4:09, Alexandre Belloni wrote:
> > Hi,
> > 
> > On 04/06/2020 20:33:01+0800, yu kuai wrote:
> > > if of_find_device_by_node() succeed, at91_pm_sram_init() doesn't have
> > > a corresponding put_device(). Thus add a jump target to fix the exception
> > > handling for this function implementation.
> > > 
> > > Fixes: d2e467905596 ("ARM: at91: pm: use the mmio-sram pool to access SRAM")
> > > Signed-off-by: yu kuai <yukuai3@...wei.com>
> > > ---
> > >   arch/arm/mach-at91/pm.c | 11 ++++++++---
> > >   1 file changed, 8 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
> > > index 074bde64064e..2aab043441e8 100644
> > > --- a/arch/arm/mach-at91/pm.c
> > > +++ b/arch/arm/mach-at91/pm.c
> > > @@ -592,13 +592,13 @@ static void __init at91_pm_sram_init(void)
> > >   	sram_pool = gen_pool_get(&pdev->dev, NULL);
> > 
> > Isn't the best solution to simply have put_device hereHi, Alexandre !
> 
> I think put_device() is supposed to be called in the exception handling
> path.
> 
> > 
> > >   	if (!sram_pool) {
> > >   		pr_warn("%s: sram pool unavailable!\n", __func__);
> > > -		return;
> > > +		goto out_put_device;
> > >   	}
> > >   	sram_base = gen_pool_alloc(sram_pool, at91_pm_suspend_in_sram_sz);
> > >   	if (!sram_base) {
> > >   		pr_warn("%s: unable to alloc sram!\n", __func__);
> > > -		return;
> > > +		goto out_put_device;
> > >   	}
> > >   	sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base);
> > > @@ -606,12 +606,17 @@ static void __init at91_pm_sram_init(void)
> > >   					at91_pm_suspend_in_sram_sz, false);
> > >   	if (!at91_suspend_sram_fn) {
> > >   		pr_warn("SRAM: Could not map\n");
> > > -		return;
> > > +		goto out_put_device;
> > >   	}
> > >   	/* Copy the pm suspend handler to SRAM */
> > >   	at91_suspend_sram_fn = fncpy(at91_suspend_sram_fn,
> > >   			&at91_pm_suspend_in_sram, at91_pm_suspend_in_sram_sz);
> 
> If nothing is wrong, maybe put_device shounld't be called?
> 

I don't think this is the case but as the reference implementation
(imx6) is carrying the patch, I'm going to apply this one.

A better fix would have been to also factorize imx_suspend_alloc_ocram,
imx6q_suspend_init, socfpga_setup_ocram_self_refresh and
at91_pm_sram_init as they were all copied from pm-imx6.c


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com