lkml.org 
[lkml]   [2019]   [Sep]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] media: v4l: cadence: Fix how unsued lanes are handled in 'csi2rx_start()'
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

\
 
 \ /
  Last update: 2019-09-17 09:06    [W:0.087 / U:0.360 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site