From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Jiri Slaby <jirislaby@kernel.org>,
linux-serial@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>,
Vladimir Zapolskiy <vz@mleia.com>,
Russell King <linux@armlinux.org.uk>,
Richard Genoud <richard.genoud@gmail.com>,
Nicolas Ferre <nicolas.ferre@microchip.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Claudiu Beznea <claudiu.beznea@microchip.com>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
NXP Linux Team <linux-imx@nxp.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-stm32@st-md-mailman.stormreply.com,
Lino Sanfilippo <LinoSanfilippo@gmx.de>
Subject: Re: [PATCH v2 4/4] serial: Add kserial_rs485 to avoid wasted space due to .padding
Date: Tue, 30 Aug 2022 10:49:34 +0200 [thread overview]
Message-ID: <Yw3PHg0imhJyb9sf@kroah.com> (raw)
In-Reply-To: <20220830072956.3630-5-ilpo.jarvinen@linux.intel.com>
On Tue, Aug 30, 2022 at 10:29:56AM +0300, Ilpo Järvinen wrote:
> The struct serial_rs485 has a .padding field to make uapi updates
> easier. It wastes space, however. Create struct kserial_rs485 which is
> a kerner counterpart w/o padding.
"kernel"?
And what is the size difference now?
> +/**
> + * struct kserial_rs485 - kernel-side struct for controlling RS485 settings.
> + * @flags: RS485 feature flags
> + * @delay_rts_before_send: Delay before send (milliseconds)
> + * @delay_rts_after_send: Delay after send (milliseconds)
> + * @addr_recv: Receive filter for RS485 addressing mode
> + * (used only when %SER_RS485_ADDR_RECV is set).
> + * @addr_dest: Destination address for RS485 addressing mode
> + * (used only when %SER_RS485_ADDR_DEST is set).
> + *
> + * Must match with struct serial_rs485 in include/uapi/linux/serial.h excluding
> + * the padding.
Why must this match? And how is that going to be enforced?
> + */
> +struct kserial_rs485 {
> + __u32 flags;
> + __u32 delay_rts_before_send;
> + __u32 delay_rts_after_send;
> + struct {
> + __u8 addr_recv;
> + __u8 addr_dest;
> + };
As this is an in-kernel structure, this should be "u32" and "u8" now.
thanks,
greg k-h
WARNING: multiple messages have this Message-ID (diff)
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
linux-doc@vger.kernel.org,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
linux-kernel@vger.kernel.org, Fabio Estevam <festevam@gmail.com>,
linux-stm32@st-md-mailman.stormreply.com,
Jonathan Corbet <corbet@lwn.net>,
Jiri Slaby <jirislaby@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Lino Sanfilippo <LinoSanfilippo@gmx.de>,
NXP Linux Team <linux-imx@nxp.com>,
linux-serial@vger.kernel.org,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Sascha Hauer <s.hauer@pengutronix.de>,
Vladimir Zapolskiy <vz@mleia.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-arm-kernel@lists.infradead.org,
Richard Genoud <richard.genoud@gmail.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Shawn Guo <shawnguo@kernel.org>,
Claudiu Beznea <claudiu.beznea@microchip.com>
Subject: Re: [PATCH v2 4/4] serial: Add kserial_rs485 to avoid wasted space due to .padding
Date: Tue, 30 Aug 2022 10:49:34 +0200 [thread overview]
Message-ID: <Yw3PHg0imhJyb9sf@kroah.com> (raw)
In-Reply-To: <20220830072956.3630-5-ilpo.jarvinen@linux.intel.com>
On Tue, Aug 30, 2022 at 10:29:56AM +0300, Ilpo Järvinen wrote:
> The struct serial_rs485 has a .padding field to make uapi updates
> easier. It wastes space, however. Create struct kserial_rs485 which is
> a kerner counterpart w/o padding.
"kernel"?
And what is the size difference now?
> +/**
> + * struct kserial_rs485 - kernel-side struct for controlling RS485 settings.
> + * @flags: RS485 feature flags
> + * @delay_rts_before_send: Delay before send (milliseconds)
> + * @delay_rts_after_send: Delay after send (milliseconds)
> + * @addr_recv: Receive filter for RS485 addressing mode
> + * (used only when %SER_RS485_ADDR_RECV is set).
> + * @addr_dest: Destination address for RS485 addressing mode
> + * (used only when %SER_RS485_ADDR_DEST is set).
> + *
> + * Must match with struct serial_rs485 in include/uapi/linux/serial.h excluding
> + * the padding.
Why must this match? And how is that going to be enforced?
> + */
> +struct kserial_rs485 {
> + __u32 flags;
> + __u32 delay_rts_before_send;
> + __u32 delay_rts_after_send;
> + struct {
> + __u8 addr_recv;
> + __u8 addr_dest;
> + };
As this is an in-kernel structure, this should be "u32" and "u8" now.
thanks,
greg k-h
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next prev parent reply other threads:[~2022-08-30 8:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 7:29 [PATCH v2 0/4] serial: Create kserial_rs485 to get rid of padding Ilpo Järvinen
2022-08-30 7:29 ` [PATCH v2 1/4] serial: Rename vars in uart_get_rs485_config() Ilpo Järvinen
2022-08-30 8:54 ` Greg Kroah-Hartman
2022-08-30 9:03 ` Ilpo Järvinen
2022-08-30 7:29 ` [PATCH v2 2/4] serial: add helpers to copy serial_rs485 from/to userspace Ilpo Järvinen
2022-08-30 7:29 ` [PATCH v2 3/4] serial: Convert serial_rs485 to kernel doc Ilpo Järvinen
2022-08-30 7:29 ` [PATCH v2 4/4] serial: Add kserial_rs485 to avoid wasted space due to .padding Ilpo Järvinen
2022-08-30 7:29 ` Ilpo Järvinen
2022-08-30 8:01 ` Jiri Slaby
2022-08-30 8:01 ` Jiri Slaby
2022-08-30 8:44 ` Ilpo Järvinen
2022-08-30 8:44 ` Ilpo Järvinen
2022-08-30 8:49 ` Greg Kroah-Hartman [this message]
2022-08-30 8:49 ` Greg Kroah-Hartman
2022-08-30 9:34 ` Ilpo Järvinen
2022-08-30 9:34 ` Ilpo Järvinen
2022-08-30 8:52 ` Greg Kroah-Hartman
2022-08-30 8:52 ` Greg Kroah-Hartman
2022-08-30 9:26 ` Ilpo Järvinen
2022-08-30 9:26 ` Ilpo Järvinen
2022-08-30 9:33 ` Greg Kroah-Hartman
2022-08-30 9:33 ` Greg Kroah-Hartman
2022-08-30 10:14 ` Ilpo Järvinen
2022-08-30 10:14 ` Ilpo Järvinen
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