linux-kernel - Re: [PATCH v3 1/9] misc: sram: fix enabled clock leak on error path

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Message-ID: <1432121401.4466.60.camel@pengutronix.de>
Date:	Wed, 20 May 2015 13:30:01 +0200
From:	Philipp Zabel <p.zabel@...gutronix.de>
To:	Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
Cc:	Heiko Stübner <heiko@...ech.de>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/9] misc: sram: fix enabled clock leak on error path

Hi Vladimir,

Am Dienstag, den 19.05.2015, 16:11 +0300 schrieb Vladimir Zapolskiy:
> Hi Philipp,
> 
> On 19.05.2015 13:41, Philipp Zabel wrote:
> > Am Montag, den 18.05.2015, 22:08 +0300 schrieb Vladimir Zapolskiy:
> >> If devm_gen_pool_create() fails, the previously enabled sram->clk is
> >> not disabled on probe() exit.
> >>
> >> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
> >> ---
> >>  drivers/misc/sram.c | 9 +++++----
> >>  1 file changed, 5 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> >> index eeaaf5f..b44a423 100644
> >> --- a/drivers/misc/sram.c
> >> +++ b/drivers/misc/sram.c
> >> @@ -90,16 +90,17 @@ static int sram_probe(struct platform_device *pdev)
> >>  	if (!sram)
> >>  		return -ENOMEM;
> >>  
> >> +	sram->pool = devm_gen_pool_create(&pdev->dev,
> >> +					  ilog2(SRAM_GRANULARITY), -1);
> >> +	if (!sram->pool)
> >> +		return -ENOMEM;
> >> +
> >>  	sram->clk = devm_clk_get(&pdev->dev, NULL);
> >>  	if (IS_ERR(sram->clk))
> >>  		sram->clk = NULL;
> >>  	else
> >>  		clk_prepare_enable(sram->clk);
> > 
> > Here you move sram->clk around, and later in patch 7 it gets moved
> > again. To me it looks like the two should be squashed together.
> 
> I agree with you, instead of moving sram->pool up it is better to place
> sram->clk right at the end of probe(), in other words this patch can be
> safely merged with patch 7 and the series becomes a bit shorter.
> 
> Thank you for the finding, I'm going to resend the change, please let me
> know your opinion about "%pa" vs "0x%llx", if it is needed to be changed
> or not.

I'd prefer to use %pa for the phys_addr_t types. You could argue that
%pa is inappropriate as those are addresses relative to the SRAM region,
not physical addresses as seen by the CPU. But following that argument,
using phys_addr_t in the first place would not be correct either. Which
leads me to question whether we will see larger than 4 GiB SRAM regions
in the foreseeable future?

regards
Philipp

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