From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Biju Das <biju.das@bp.renesas.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
Alessandro Zummo <a.zummo@towertech.it>,
Geert Uytterhoeven <geert+renesas@glider.be>,
linux-rtc@vger.kernel.org, Simon Horman <horms@verge.net.au>,
Chris Paterson <Chris.Paterson2@renesas.com>,
Fabrizio Castro <fabrizio.castro@bp.renesas.com>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Subject: Re: [PATCH v3 2/4] rtc: pcf85363: Add support for NXP pcf85263 rtc
Date: Fri, 7 Dec 2018 10:45:38 +0100 [thread overview]
Message-ID: <CAMuHMdUXPPEqKiXC6reGkEUUAMUEK5Ku+zbDv0BS7KMVUYQGhQ@mail.gmail.com> (raw)
In-Reply-To: <OSBPR01MB2103D626F5A58D86D726E721B8AA0@OSBPR01MB2103.jpnprd01.prod.outlook.com>
Hi Biju,
On Fri, Dec 7, 2018 at 10:34 AM Biju Das <biju.das@bp.renesas.com> wrote:
> > Subject: Re: [PATCH v3 2/4] rtc: pcf85363: Add support for NXP pcf85263 rtc
> >
> > On 06/12/2018 15:49:57+0000, Biju Das wrote:
> > > > Subject: Re: [PATCH v3 2/4] rtc: pcf85363: Add support for NXP
> > > > pcf85263 rtc
> > > > On Thu, Dec 6, 2018 at 4:24 PM Biju Das <biju.das@bp.renesas.com>
> > wrote:
> > > > > > Subject: Re: [PATCH v3 2/4] rtc: pcf85363: Add support for NXP
> > > > > > pcf85263 rtc CC nvmem maintainer
> > > > > > Given bytes should be 1, val should be a pointer to a single byte...
> > > > > > What if bytes == 0?
> > > > >
> > > > > I doubt we get "bytes==0" because of the checks in "
> > > > drivers/nvmem/core.c"
> > > > > Function " bin_attr_nvmem_read/ bin_attr_nvmem_write".
> > > >
> > > > Depends. There are other functions calling nvmem_reg_{read,write}(),
> > e.g.
> > > > nvmem_device_{read,write}().
> > >
> > > OK. In that case, I will return (-EINVAL) for "bytes !=1"
> >
> > I think it is probably better to ensure the nvmem core never passes an invalid
> > number of bytes. All the ther RTC drivers make that assumption.
>
> In that case, I will do following checks in nvmem_device_{read,write}() before calling nvmem_reg_{read,write}(),
>
> nvmem_device_read
>
> /* Stop the user from reading */
> if (offset >= nvmem->size)
> return 0;
>
> if (bytes == 0)
> return -EINVAL;
Why not 0?
>
> if (offset + bytes > nvmem->size)
This might overflow, please use check_add_overflow().
> bytes = nvmem->size - offset;
>
> nvmem_device_write
>
> /* Stop the user from writing */
> if (offset >= nvmem->size)
> return -EFBIG;
ENOSPC?
+ same comments as for read.
Oh, and offset is unsigned int instead of loff_t.
Nobody's envisioning nvmem devices larger than 4 GiB?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2018-12-07 9:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 8:55 [PATCH v3 0/4] Add NXP pcf85263 real-time clock support Biju Das
2018-12-06 8:55 ` [PATCH v3 1/4] dt-bindings: rtc: pcf85363: Document pcf85263 real-time clock Biju Das
2018-12-06 9:13 ` Geert Uytterhoeven
2018-12-06 8:55 ` [PATCH v3 2/4] rtc: pcf85363: Add support for NXP pcf85263 rtc Biju Das
2018-12-06 9:39 ` Geert Uytterhoeven
2018-12-06 15:24 ` Biju Das
2018-12-06 15:37 ` Geert Uytterhoeven
2018-12-06 15:49 ` Biju Das
2018-12-06 16:52 ` Alexandre Belloni
2018-12-07 9:34 ` Biju Das
2018-12-07 9:45 ` Geert Uytterhoeven [this message]
2018-12-07 10:16 ` Biju Das
2018-12-07 10:18 ` Geert Uytterhoeven
2018-12-06 8:55 ` [PATCH v3 3/4] ARM: shmobile: Enable NXP pcf85363 rtc in shmobile_defconfig Biju Das
2018-12-06 9:41 ` Geert Uytterhoeven
2018-12-06 8:55 ` [PATCH v3 4/4] ARM: dts: iwg23s-sbc: Enable RTC Biju Das
2018-12-06 9:55 ` Geert Uytterhoeven
2018-12-06 12:40 ` Biju Das
2018-12-06 12:59 ` Geert Uytterhoeven
2018-12-10 11:52 ` Simon Horman
2018-12-10 11:56 ` Geert Uytterhoeven
2018-12-10 12:15 ` Simon Horman
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