| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20220611145034.07efd279@jic23-huawei>
Date: Sat, 11 Jun 2022 14:50:34 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc: Yury Norov <yury.norov@...il.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Andrew Morton <akpm@...ux-foundation.org>,
Michał Mirosław <mirq-linux@...e.qmqm.pl>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Peter Zijlstra <peterz@...radead.org>,
David Laight <David.Laight@...lab.com>,
Joe Perches <joe@...ches.com>, Dennis Zhou <dennis@...nel.org>,
Emil Renner Berthing <kernel@...il.dk>,
Nicholas Piggin <npiggin@...il.com>,
Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
Alexey Klimov <aklimov@...hat.com>,
linux-kernel@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>,
Alexandru Ardelean <alexandru.ardelean@...log.com>,
Nathan Chancellor <nathan@...nel.org>,
linux-iio@...r.kernel.org
Subject: Re: [PATCH 04/49] iio: fix opencoded for_each_set_bit()
On Sat, 4 Jun 2022 16:41:13 +0100
Jonathan Cameron <jic23@...nel.org> wrote:
> On Fri, 11 Feb 2022 18:17:37 +0100
> Christophe JAILLET <christophe.jaillet@...adoo.fr> wrote:
>
> > Le 10/02/2022 à 23:48, Yury Norov a écrit :
> > > iio_simple_dummy_trigger_h() is mostly an opencoded for_each_set_bit().
> > > Using for_each_set_bit() make code much cleaner, and more effective.
> > >
> > > Signed-off-by: Yury Norov <yury.norov-Re5JQEeQqe8AvxtiuMwx3w@...lic.gmane.org>
> > > ---
> > > drivers/iio/dummy/iio_simple_dummy_buffer.c | 48 ++++++++-------------
> > > 1 file changed, 19 insertions(+), 29 deletions(-)
> > >
> > > diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c
> > > index d81c2b2dad82..3bc1b7529e2a 100644
> > > --- a/drivers/iio/dummy/iio_simple_dummy_buffer.c
> > > +++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
> > > @@ -45,41 +45,31 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
> > > {
> > > struct iio_poll_func *pf = p;
> > > struct iio_dev *indio_dev = pf->indio_dev;
> > > + int i = 0, j;
> > > u16 *data;
> > >
> > > data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> > > if (!data)
> > > goto done;
> > >
> > > - if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) {
> > > - /*
> > > - * Three common options here:
> > > - * hardware scans: certain combinations of channels make
> > > - * up a fast read. The capture will consist of all of them.
> > > - * Hence we just call the grab data function and fill the
> > > - * buffer without processing.
> > > - * software scans: can be considered to be random access
> > > - * so efficient reading is just a case of minimal bus
> > > - * transactions.
> > > - * software culled hardware scans:
> > > - * occasionally a driver may process the nearest hardware
> > > - * scan to avoid storing elements that are not desired. This
> > > - * is the fiddliest option by far.
> > > - * Here let's pretend we have random access. And the values are
> > > - * in the constant table fakedata.
> > > - */
> > > - int i, j;
> > > -
> > > - for (i = 0, j = 0;
> > > - i < bitmap_weight(indio_dev->active_scan_mask,
> > > - indio_dev->masklength);
> > > - i++, j++) {
> > > - j = find_next_bit(indio_dev->active_scan_mask,
> > > - indio_dev->masklength, j);
> > > - /* random access read from the 'device' */
> > > - data[i] = fakedata[j];
> > > - }
> > > - }
> > > + /*
> > > + * Three common options here:
> > > + * hardware scans: certain combinations of channels make
> > > + * up a fast read. The capture will consist of all of them.
> > > + * Hence we just call the grab data function and fill the
> > > + * buffer without processing.
> > > + * software scans: can be considered to be random access
> > > + * so efficient reading is just a case of minimal bus
> > > + * transactions.
> > > + * software culled hardware scans:
> > > + * occasionally a driver may process the nearest hardware
> > > + * scan to avoid storing elements that are not desired. This
> > > + * is the fiddliest option by far.
> > > + * Here let's pretend we have random access. And the values are
> > > + * in the constant table fakedata.
> > > + */
> >
> > Nitpicking: you could take advantage of the tab you save to use the full
> > width of the line and save some lines of code.
>
> Tweaked whilst applying.
>
> Sorry this one took so long. I marked it as a patch that I'd revisit if and
> tidy up if there was no v2 sent, but then managed to forget about it until
> I came to do a clean out of patchwork today.
>
> Anyhow, now applied to the togreg branch of iio.git - initially pushed out
> as testing for 0-day to see if we missed anything.
And dropped again during a rebase as a different version has gone upstream
through a pull request to Linus.
Whilst I have no strong opinion on that in general, I am a little grumpy
that a version was merged that was never posted to the mailing lists (that
I can find on lore.kernel.org.) Sure the changes were minor and easy to verify
as harmless, but none the less they should have been posted.
Jonathan
>
> Thanks,
>
> Jonathan
>
> >
> > Just my 2c.
> >
> > CJ
> >
> >
> > > + for_each_set_bit(j, indio_dev->active_scan_mask, indio_dev->masklength)
> > > + data[i++] = fakedata[j];
> > >
> > > iio_push_to_buffers_with_timestamp(indio_dev, data,
> > > iio_get_time_ns(indio_dev));
> >
>
Powered by blists - more mailing lists