From: Jason Gunthorpe <jgg@nvidia.com>
To: Tzung-Bi Shih <tzungbi@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Benson Leung <bleung@chromium.org>,
linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev,
"Rafael J. Wysocki" <rafael@kernel.org>,
Danilo Krummrich <dakr@kernel.org>,
Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Johan Hovold <johan@kernel.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH 3/8] char: misc: Introduce misc_sync_register()
Date: Sat, 9 May 2026 13:32:07 -0300 [thread overview]
Message-ID: <20260509163207.GK9254@nvidia.com> (raw)
In-Reply-To: <af8BJCaJYVBr_P3u@tzungbi-laptop>
On Sat, May 09, 2026 at 05:40:52PM +0800, Tzung-Bi Shih wrote:
> > The drivers ops lookup needs to be O(1) on the system call path.
>
> Achieving O(1) lookup is currently infeasible for the misc subsystem.
> This is because misc devices use the minor number[5] as a search key to
> determine which miscdevice the file operation is tied to, which
> inherently involves a linear search.
So? It needs a solution, you can't just give up.
Probably it will need driver changes, maybe focus on cdev_device_add()
drivers first.
Jason
next prev parent reply other threads:[~2026-05-09 16:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-27 13:46 [PATCH 0/8] char: misc: Introduce misc_sync to fix UAF Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 1/8] char: misc: Simplify locking with guard() Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 2/8] char: misc: Introduce misc_find() helper Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 3/8] char: misc: Introduce misc_sync_register() Tzung-Bi Shih
2026-04-28 16:09 ` Jason Gunthorpe
2026-05-08 9:38 ` Tzung-Bi Shih
2026-05-08 11:54 ` Jason Gunthorpe
2026-05-09 9:40 ` Tzung-Bi Shih
2026-05-09 16:32 ` Jason Gunthorpe [this message]
2026-04-27 13:46 ` [PATCH 4/8] char: misc: Use SRCU to protect list traversal Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 5/8] platform/chrome: cros_ec_chardev: Introduce chardev_data Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 6/8] platform/chrome: cros_ec_chardev: Move data to chardev_pdata Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 7/8] platform/chrome: cros_ec_chardev: Add event relayer Tzung-Bi Shih
2026-04-27 13:46 ` [PATCH 8/8] platform/chrome: cros_ec_chardev: Use misc_sync_register() Tzung-Bi Shih
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