From: Greg KH <gregkh@linuxfoundation.org>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: ming.lei@canonical.com, bp@alien8.de, wagi@monom.org,
teg@jklm.no, mchehab@osg.samsung.com, zajec5@gmail.com,
linux-kernel@vger.kernel.org, markivx@codeaurora.org,
stephen.boyd@linaro.org, broonie@kernel.org,
zohar@linux.vnet.ibm.com, tiwai@suse.de,
johannes@sipsolutions.net, chunkeey@googlemail.com,
hauke@hauke-m.de, jwboyer@fedoraproject.org,
dmitry.torokhov@gmail.com, dwmw2@infradead.org, jslaby@suse.com,
torvalds@linux-foundation.org, luto@amacapital.net,
fengguang.wu@intel.com, rpurdie@rpsys.net,
j.anaszewski@samsung.com, Abhay_Salunke@dell.com,
Julia.Lawall@lip6.fr, Gilles.Muller@lip6.fr,
nicolas.palix@imag.fr, dhowells@redhat.com,
bjorn.andersson@linaro.org, arend.vanspriel@broadcom.com,
kvalo@codeaurora.org, linux-leds@vger.kernel.org
Subject: Re: [PATCH v4 2/2] firmware: add DECLARE_FW_CUSTOM_FALLBACK() annotation
Date: Thu, 19 Jan 2017 12:31:11 +0100 [thread overview]
Message-ID: <20170119113111.GO28024@kroah.com> (raw)
In-Reply-To: <20170112144250.12376-3-mcgrof@kernel.org>
On Thu, Jan 12, 2017 at 06:42:50AM -0800, Luis R. Rodriguez wrote:
> We need to ensure that when driver developers use the custom firmware
> fallback mechanism it was not a copy and paste bug. These use cases on
> upstream drivers are rare, we only have 2 upstream users and its for
> really old drivers. Since valid uses are rare but possible enable a
> white-list for its use, and use this same white-list annotation to refer
> to the documentation covering the custom use case.
>
> New faulty users can be reported via 0-day now.
>
> v2: change dependencies on rules make more sense, and fixed
> context mode
>
> Cc: Fengguang Wu <fengguang.wu@intel.com>
> Cc: Richard Purdie <rpurdie@rpsys.net>
> Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
> Cc: linux-leds@vger.kernel.org
> Cc: Abhay Salunke <Abhay_Salunke@dell.com>
> Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
> ---
> Documentation/driver-api/firmware/fallback-mechanisms.rst | 7 +++++--
> drivers/firmware/dell_rbu.c | 1 +
> drivers/leds/leds-lp55xx-common.c | 1 +
> include/linux/firmware.h | 7 +++++++
> scripts/coccinelle/api/request_firmware-custom-fallback.cocci | 9 ++++++++-
> 5 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/driver-api/firmware/fallback-mechanisms.rst b/Documentation/driver-api/firmware/fallback-mechanisms.rst
> index b87a292153c6..73f509a8d2de 100644
> --- a/Documentation/driver-api/firmware/fallback-mechanisms.rst
> +++ b/Documentation/driver-api/firmware/fallback-mechanisms.rst
> @@ -184,8 +184,11 @@ load firmware for you through a custom path.
>
> The custom fallback mechanism can often be enabled by mistake. We currently
> have only 2 users of it, and little justification to enable it for other users.
> -Since it is a common driver developer mistake to enable it, help police for
> -new users of the custom fallback mechanism with::
> +Since it is a common driver developer mistake to enable it, driver developers
> +should use DECLARE_FW_CUSTOM_FALLBACK() to both white-list and validate their
> +use and also refer to the documentation for the custom loading solution.
> +
> +Invalid users of the custom fallback mechanism can be policed using::
Ick, no, why? Why not just add a checkpatch rule instead?
>
> $ export COCCI=scripts/coccinelle/api/request_firmware-avoid-init-probe-init.cocci
> $ make coccicheck MODE=report
> diff --git a/drivers/firmware/dell_rbu.c b/drivers/firmware/dell_rbu.c
> index 2f452f1f7c8a..3f2aa35bc54d 100644
> --- a/drivers/firmware/dell_rbu.c
> +++ b/drivers/firmware/dell_rbu.c
> @@ -586,6 +586,7 @@ static ssize_t read_rbu_image_type(struct file *filp, struct kobject *kobj,
> return size;
> }
>
> +DECLARE_FW_CUSTOM_FALLBACK("Documentation/dell_rbu.txt");
That's a pain.
> static ssize_t write_rbu_image_type(struct file *filp, struct kobject *kobj,
> struct bin_attribute *bin_attr,
> char *buffer, loff_t pos, size_t count)
> diff --git a/drivers/leds/leds-lp55xx-common.c b/drivers/leds/leds-lp55xx-common.c
> index 5377f22ff994..04161428ee3b 100644
> --- a/drivers/leds/leds-lp55xx-common.c
> +++ b/drivers/leds/leds-lp55xx-common.c
> @@ -219,6 +219,7 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
> release_firmware(chip->fw);
> }
>
> +DECLARE_FW_CUSTOM_FALLBACK("Documentation/leds/leds-lp55xx.txt");
Same here.
> static int lp55xx_request_firmware(struct lp55xx_chip *chip)
> {
> const char *name = chip->cl->name;
> diff --git a/include/linux/firmware.h b/include/linux/firmware.h
> index b1f9f0ccb8ac..e6ca19c03dcc 100644
> --- a/include/linux/firmware.h
> +++ b/include/linux/firmware.h
> @@ -8,6 +8,13 @@
> #define FW_ACTION_NOHOTPLUG 0
> #define FW_ACTION_HOTPLUG 1
>
> +/*
> + * Helper for scripts/coccinelle/api/request_firmware-custom-fallback.cocci
> + * and so users can also easily search for the documentation for the
> + * respectively needed custom fallback mechanism.
> + */
> +#define DECLARE_FW_CUSTOM_FALLBACK(__usermode_helper)
So you really don't need to put anything "valid" in the define argument?
This feels like such a horrid hack, I really don't like it, especially
as we don't do it anywhere else in the kernel, right? Why start now?
thanks,
greg k-h
next prev parent reply other threads:[~2017-01-19 11:39 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-13 3:08 [PATCH 0/5] firmware: doc revamp Luis R. Rodriguez
2016-12-13 3:08 ` [PATCH 1/5] selftests: firmware: only modprobe if driver is missing Luis R. Rodriguez
2016-12-13 3:08 ` [PATCH 2/5] selftests: firmware: send expected errors to /dev/null Luis R. Rodriguez
2016-12-13 3:08 ` [PATCH 3/5] firmware: revamp firmware documentation Luis R. Rodriguez
2016-12-13 7:26 ` Rafał Miłecki
2016-12-16 9:09 ` Luis R. Rodriguez
2016-12-13 13:26 ` Daniel Wagner
2016-12-13 13:30 ` Rafał Miłecki
2016-12-16 9:18 ` Luis R. Rodriguez
2016-12-16 9:34 ` Johannes Berg
2016-12-16 9:16 ` Luis R. Rodriguez
2017-01-12 14:42 ` [PATCH v4 0/2] firmware: fw doc revamp follow up Luis R. Rodriguez
2017-01-12 14:42 ` [PATCH v4 1/2] firmware: add SmPL report for custom fallback mechanism Luis R. Rodriguez
2017-01-12 14:42 ` [PATCH v4 2/2] firmware: add DECLARE_FW_CUSTOM_FALLBACK() annotation Luis R. Rodriguez
2017-01-19 11:31 ` Greg KH [this message]
2017-01-19 16:08 ` Luis R. Rodriguez
2017-01-19 16:14 ` Greg KH
2017-01-19 21:38 ` Luis R. Rodriguez
2016-12-13 3:08 ` [PATCH 4/5] firmware: add SmPL report for custom fallback mechanism Luis R. Rodriguez
2016-12-13 6:13 ` Julia Lawall
2016-12-13 9:44 ` Jacek Anaszewski
2016-12-14 1:48 ` Milo Kim
2016-12-16 9:29 ` Luis R. Rodriguez
2017-01-11 18:51 ` Luis R. Rodriguez
2016-12-13 3:08 ` [PATCH 5/5] firmware: add DECLARE_FW_CUSTOM_FALLBACK() annotation Luis R. Rodriguez
2016-12-13 19:04 ` Pavel Machek
2016-12-16 9:22 ` Luis R. Rodriguez
2016-12-16 9:29 ` Pavel Machek
2016-12-16 9:59 ` Luis R. Rodriguez
2016-12-16 10:14 ` Pavel Machek
2016-12-16 10:56 ` Luis R. Rodriguez
2016-12-16 11:27 ` Pavel Machek
2016-12-16 15:19 ` Luis R. Rodriguez
2016-12-16 16:10 ` Luis R. Rodriguez
2016-12-16 16:14 ` Luis R. Rodriguez
2016-12-18 3:50 ` Milo Kim
2016-12-19 20:08 ` Pavel Machek
2016-12-19 20:46 ` Jacek Anaszewski
2016-12-21 18:49 ` Pavel Machek
2016-12-21 20:33 ` Jacek Anaszewski
2016-12-15 9:32 ` Jacek Anaszewski
2016-12-16 9:26 ` Luis R. Rodriguez
2016-12-13 12:58 ` [PATCH 0/5] firmware: doc revamp Daniel Wagner
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