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Tue, 18 Aug 2026 19:46:10 -0700 (PDT) From: kr494167@gmail.com To: andy.shevchenko@gmail.com, andy@kernel.org, geert@linux-m68k.org Cc: chris.packham@alliedtelesis.co.nz, linux-kernel@vger.kernel.org, Surendra Singh Chouhan Subject: [PATCH 0/3 1/3] auxdisplay: line-display: add devm_linedisp_register() Date: Wed, 19 Aug 2026 08:15:54 +0530 Message-ID: <20260819024556.63534-2-kr494167@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260819024556.63534-1-kr494167@gmail.com> References: <20260819024556.63534-1-kr494167@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Surendra Singh Chouhan Add devm_linedisp_register() to manage character line display registration via devres. This simplifies driver cleanup and prevents use-after-free bugs when unregistering line displays on driver detach. Signed-off-by: Surendra Singh Chouhan --- drivers/auxdisplay/line-display.c | 32 +++++++++++++++++++++++++++++++ drivers/auxdisplay/line-display.h | 2 ++ 2 files changed, 34 insertions(+) diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c index 915eb5cd96b2..6fd0b870e16a 100644 --- a/drivers/auxdisplay/line-display.c +++ b/drivers/auxdisplay/line-display.c @@ -592,5 +592,37 @@ void linedisp_unregister(struct linedisp *linedisp) } EXPORT_SYMBOL_NS_GPL(linedisp_unregister, "LINEDISP"); +static void devm_linedisp_unregister(void *data) +{ + struct linedisp *linedisp = data; + + linedisp_unregister(linedisp); +} + +/** + * devm_linedisp_register - register a character line display + * @dev: device being registered + * @linedisp: pointer to character line display structure + * @num_chars: the number of characters that can be displayed + * @ops: character line display operations + * + * Managed linedisp_register(). Line display registered with this function will + * automatically be unregistered on driver detach. + * + * Return: zero on success, else a negative error code. + */ +int devm_linedisp_register(struct device *dev, struct linedisp *linedisp, + unsigned int num_chars, const struct linedisp_ops *ops) +{ + int err; + + err = linedisp_register(linedisp, dev, num_chars, ops); + if (err) + return err; + + return devm_add_action_or_reset(dev, devm_linedisp_unregister, linedisp); +} +EXPORT_SYMBOL_NS_GPL(devm_linedisp_register, "LINEDISP"); + MODULE_DESCRIPTION("Character line display core support"); MODULE_LICENSE("GPL"); diff --git a/drivers/auxdisplay/line-display.h b/drivers/auxdisplay/line-display.h index 36853b639711..cd1b94829f72 100644 --- a/drivers/auxdisplay/line-display.h +++ b/drivers/auxdisplay/line-display.h @@ -88,5 +88,7 @@ void linedisp_detach(struct device *dev); int linedisp_register(struct linedisp *linedisp, struct device *parent, unsigned int num_chars, const struct linedisp_ops *ops); void linedisp_unregister(struct linedisp *linedisp); +int devm_linedisp_register(struct device *dev, struct linedisp *linedisp, + unsigned int num_chars, const struct linedisp_ops *ops); #endif /* LINEDISP_H */ -- 2.55.0