From: "Ardelean, Alexandru" <alexandru.Ardelean@analog.com>
To: "jic23@kernel.org" <jic23@kernel.org>,
"rohitsarkar5398@gmail.com" <rohitsarkar5398@gmail.com>
Cc: "stefan.popa@analog.com" <stefan.popa@analog.com>,
"zhongjiang@huawei.com" <zhongjiang@huawei.com>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
"Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
"pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
"knaack.h@gmx.de" <knaack.h@gmx.de>,
"Hennerich, Michael" <Michael.Hennerich@analog.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"lars@metafoo.de" <lars@metafoo.de>
Subject: Re: [PATCH 0/2] use DEFINE_DEBUGFS_ATTRIBUTE instead of DEFINE_SIMPLE_ATTRIBUTE
Date: Mon, 30 Mar 2020 09:20:13 +0000 [thread overview]
Message-ID: <aee10d6bfc5f2fef85d90245304f3e0f368f94ec.camel@analog.com> (raw)
In-Reply-To: <20200329103818.2fce9529@archlinux>
On Sun, 2020-03-29 at 10:38 +0100, Jonathan Cameron wrote:
> On Sat, 28 Mar 2020 12:04:53 +0530
> Rohit Sarkar <rohitsarkar5398@gmail.com> wrote:
>
> > The debugfs_create_file_unsafe method does not protect the fops given to
> > it from file removal. It must be used with DEFINE_DEBUGFS_ATTRIBUTE
> > which makes the fops aware of the file lifetime.
> >
> > Further using DEFINE_DEBUGFS_ATTRIBUTE along with
> > debugfs_create_file_unsafe significantly reduces the overhead introduced by
> > debugfs_create_file which creates a lifetime managing proxy around each
> > fops handed in. Refer [1] for more on this.
> >
> > Fixes the following warnings reported by coccinelle:
> > drivers/iio/imu//adis16460.c:126:0-23: WARNING: adis16460_flash_count_fops
> > should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> > drivers/iio/imu//adis16460.c:108:0-23: WARNING: adis16460_product_id_fops
> > should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> > drivers/iio/imu//adis16460.c:90:0-23: WARNING: adis16460_serial_number_fops
> > should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> > drivers/iio/imu//adis16400.c:278:0-23: WARNING: adis16400_flash_count_fops
> > should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> > drivers/iio/imu//adis16400.c:261:0-23: WARNING: adis16400_product_id_fops
> > should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> >
> > [1]: https://lists.gt.net/linux/kernel/2369498
> >
> > Rohit Sarkar (2):
> > iio: imu: adis16400: use DEFINE_DEBUGFS_ATTRIBUTE instead of
> > DEFINE_SIMPLE_ATTRIBUTE
> > iio: imu: adis16460: use DEFINE_DEBUGFS_ATTRIBUTE instead of
> > DEFINE_SIMPLE_ATTRIBUTE
> >
> > drivers/iio/imu/adis16400.c | 4 ++--
> > drivers/iio/imu/adis16460.c | 6 +++---
> > 2 files changed, 5 insertions(+), 5 deletions(-)
> >
> Hi Rohit,
>
> You've opened a can of worms with this one. There as a previous series
> posted doing exactly this change back in 2019 by Zhong Jiang (cc'd)
>
> At the time I did a bit of looking into why this had been universally taken
> up cross tree and turned out there are some potential issues.
>
> Alexandru added it to the list of things to test, but I guess it got
> buried under other work and is still outstanding.
>
yep
my bad;
will try to make room these days for that old one
> https://lkml.org/lkml/2019/10/30/144
>
> Has Greg KH raising the point that file reference counting is changed (as you
> mention) but that can cause subtle bugs. It 'might' be fine but is
> definitely one that needs a tested-by from someone with the hardware.
>
> Jonathan
next prev parent reply other threads:[~2020-03-30 9:20 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-28 6:34 [PATCH 0/2] use DEFINE_DEBUGFS_ATTRIBUTE instead of DEFINE_SIMPLE_ATTRIBUTE Rohit Sarkar
2020-03-28 6:34 ` [PATCH 1/2] iio: imu: adis16400: " Rohit Sarkar
2020-03-28 6:34 ` [PATCH 2/2] iio: imu: adis16460: " Rohit Sarkar
2020-03-29 9:38 ` [PATCH 0/2] " Jonathan Cameron
2020-03-29 11:34 ` Rohit Sarkar
2020-03-29 13:46 ` Lars-Peter Clausen
2020-03-29 15:39 ` Rohit Sarkar
2020-03-30 9:20 ` Ardelean, Alexandru [this message]
2020-03-31 10:58 ` Sa, Nuno
2020-03-31 11:08 ` Lars-Peter Clausen
2020-03-31 11:19 ` Rohit Sarkar
2020-03-31 11:49 ` Rohit Sarkar
2020-03-31 15:30 ` Sa, Nuno
2020-03-31 11:47 ` [PATCH v2 " Rohit Sarkar
2020-03-31 11:47 ` [PATCH v2 1/2] iio: imu: adis16400: " Rohit Sarkar
2020-03-31 15:28 ` Sa, Nuno
2020-04-04 15:32 ` Jonathan Cameron
2020-03-31 11:47 ` [PATCH v2 2/2] iio: imu: adis16460: " Rohit Sarkar
2020-03-31 15:28 ` Sa, Nuno
2020-04-04 15:34 ` Jonathan Cameron
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