From: Dan Carpenter <dan.carpenter@oracle.com>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Maxime Ripard <mripard@kernel.org>,
mchehab@kernel.org, linux-media@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] media: v4l: cadence: Fix how unsued lanes are handled in 'csi2rx_start()'
Date: Tue, 17 Sep 2019 10:06:13 +0300 [thread overview]
Message-ID: <20190917070613.GA2959@kadam> (raw)
In-Reply-To: <f67787da-dc1c-3e05-c1e2-e8737641dfd0@wanadoo.fr>
On Mon, Sep 16, 2019 at 09:24:26PM +0200, Christophe JAILLET wrote:
> Le 16/09/2019 à 08:28, Dan Carpenter a écrit :
> > On Fri, Sep 13, 2019 at 09:57:09AM +0200, Maxime Ripard wrote:
> > > Hi Christophe,
> > >
> > > On Thu, Sep 12, 2019 at 10:44:50PM +0200, Christophe JAILLET wrote:
> > > > The 2nd parameter of 'find_first_zero_bit()' is a number of bits, not of
> > > > bytes. So use 'BITS_PER_LONG' instead of 'sizeof(lanes_used)'.
> > > >
> > > > Fixes: 1fc3b37f34f6 ("media: v4l: cadence: Add Cadence MIPI-CSI2 RX driver")
> > > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > > > ---
> > > > This patch is purely speculative. Using BITS_PER_LONG looks logical to me,
> > > > but I'm not 100% sure that it is what is expected here. 'csi2rx->max_lanes'
> > > > could also be a good candidate.
> > > Yeah, csi2rx->max_lanes would make more sense in that context. Could
> > > you resend a new version?
> > This is sort of unrelated, but for Smatch purposes the csi2rx->max_lanes
> > comes from the firmware in csi2rx_parse_dt() and it could be any u8
> > value.
>
> Hi Dan,
>
> not sure to follow you.
>
> csi2rx_probe()
> --> csi2rx_get_resources()
> --> ...
> dev_cfg = readl(csi2rx->base + CSI2RX_DEVICE_CFG_REG);
> ...
> csi2rx->max_lanes = dev_cfg & 7;
> if (csi2rx->max_lanes > CSI2RX_LANES_MAX) {
> dev_err(&pdev->dev, "Invalid number of lanes: %u\n",
> csi2rx->max_lanes);
> return -EINVAL;
> }
>
> So I guess, that we can trust max_lanes because of the 'if (... >
> CSI2RX_LANES_MAX)' check.
>
> Did I miss something?
Ugh... I was looking at ->num_lanes and I was also just totally wrong.
Smatch parses that badly. Smatch actually parses ->max_lanes correctly
though so that's ok.
Sorry for the noise on this.
regards,
dan carpenter
next prev parent reply other threads:[~2019-09-17 7:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-12 20:44 [PATCH] media: v4l: cadence: Fix how unsued lanes are handled in 'csi2rx_start()' Christophe JAILLET
2019-09-13 7:14 ` walter harms
2019-09-13 7:57 ` Maxime Ripard
2019-09-16 6:28 ` Dan Carpenter
2019-09-16 19:24 ` Christophe JAILLET
2019-09-17 7:06 ` Dan Carpenter [this message]
2019-09-17 7:52 ` Marc Gonzalez
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