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Date:   Wed, 10 Aug 2022 09:00:34 -0700
Message-Id: <20220810085753.v5.1.I5622b2a92dca4d2703a0f747e24f3ef19303e6df@changeid>
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Subject: [PATCH v5 1/5] sysfs: Add attribute info for /sys/devices/.../coredump_disabled
From:   Manish Mandlik <mmandlik@google.com>
To:     Arend van Spriel <aspriel@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        marcel@holtmann.org, luiz.dentz@gmail.com
Cc:     Johannes Berg <johannes@sipsolutions.net>,
        Dan Williams <dan.j.williams@intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        "Signed-off-by : Manish Mandlik" <mmandlik@google.com>,
        linux-bluetooth@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        chromeos-bluetooth-upstreaming@chromium.org,
        Won Chung <wonchung@google.com>,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
        linux-kernel@vger.kernel.org
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Precedence: bulk

This patch adds the specification for /sys/devices/.../coredump_disabled
attribute which allows the userspace to enable/disable devcoredump for a
particular device and drivers can use it to enable/disable functionality
accordingly. It is available when the CONFIG_DEV_COREDUMP is enabled and
driver has implemented the .coredump() callback.

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Manish Mandlik <mmandlik@google.com>
---
Hi Arend, Greg,

The existing /sys/class/devcoredump/disabled provides only a one-way
disable functionality for devcoredump. It also disables the devcoredump
for everyone who is using it.

This and the next patch provides a way to selectively enable/disable the
devcoredump by creating a /sys/devices/.../coredump_disabled sysfs entry.
The userspace can write 0/1 to it to enable/disable devcoredump for that
particular device and drivers can use it accordingly. It will only be
available along with the /sys/devices/.../coredump sysfs entry when the
CONFIG_DEV_COREDUMP is enabled and the driver has implemented the
.coredump() callback.

Please let me know what you think about this.

Thanks,
Manish.

(no changes since v4)

Changes in v4:
- New patch in the series

 Documentation/ABI/testing/sysfs-devices-coredump | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-coredump b/Documentation/ABI/testing/sysfs-devices-coredump
index e459368533a4..4bcfc7dbad67 100644
--- a/Documentation/ABI/testing/sysfs-devices-coredump
+++ b/Documentation/ABI/testing/sysfs-devices-coredump
@@ -8,3 +8,17 @@ Description:
 		file will trigger the .coredump() callback.
 
 		Available when CONFIG_DEV_COREDUMP is enabled.
+
+What:		/sys/devices/.../coredump_disabled
+Date:		July 2022
+Contact:	Manish Mandlik <mmandlik@google.com>
+Description:
+		The /sys/devices/.../coredump_disabled attribute can be used by
+		drivers to selectively enable/disable devcoredump functionality
+		for a device. The userspace can write 0/1 to it to control
+		enabling/disabling of devcoredump for that particular device.
+		This attribute is present only when the device is bound to a
+		driver which implements the .coredump() callback. The attribute
+		is readable and writeable.
+
+		Available when CONFIG_DEV_COREDUMP is enabled.
-- 
2.37.1.559.g78731f0fdb-goog