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From: Dan Carpenter <error27@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Umang Jain <umang.jain@ideasonboard.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Ray Jui <rjui@broadcom.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-rpi-kernel@lists.infradead.org,
	linux-staging@lists.linux.dev
Subject: Re: [PATCH 1/3] Revert "staging: mmal-vchiq: Avoid use of bool in structures"
Date: Fri, 18 Nov 2022 11:35:52 +0300	[thread overview]
Message-ID: <Y3dD6Lg2L7CgkDFe@kadam> (raw)
In-Reply-To: <Y3bN8I7DlxRUZumH@lunn.ch>

On Fri, Nov 18, 2022 at 01:12:32AM +0100, Andrew Lunn wrote:
> 
> Does :1 really initialise the variable?

Obviously not.

> In "u32 enabled:1" it means
> this is a 1 bit wide bit field. It seems odd that bool is somehow
> special and :1 means something else.

If you have a bunch of consecutive bool a:1; bool b:1; then GCC will
squeeze them into the same byte.  But if you have bool a; bool b; then
they each take a byte with GCC.  I have specified GCC because the size
of bool types are a bit vague in the C standard.

regards,
dan carpenter

WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <error27@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Umang Jain <umang.jain@ideasonboard.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kieran Bingham <kieran.bingham@ideasonboard.com>,
	Broadcom internal kernel review list
	<bcm-kernel-feedback-list@broadcom.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Ray Jui <rjui@broadcom.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-rpi-kernel@lists.infradead.org,
	linux-staging@lists.linux.dev
Subject: Re: [PATCH 1/3] Revert "staging: mmal-vchiq: Avoid use of bool in structures"
Date: Fri, 18 Nov 2022 11:35:52 +0300	[thread overview]
Message-ID: <Y3dD6Lg2L7CgkDFe@kadam> (raw)
In-Reply-To: <Y3bN8I7DlxRUZumH@lunn.ch>

On Fri, Nov 18, 2022 at 01:12:32AM +0100, Andrew Lunn wrote:
> 
> Does :1 really initialise the variable?

Obviously not.

> In "u32 enabled:1" it means
> this is a 1 bit wide bit field. It seems odd that bool is somehow
> special and :1 means something else.

If you have a bunch of consecutive bool a:1; bool b:1; then GCC will
squeeze them into the same byte.  But if you have bool a; bool b; then
they each take a byte with GCC.  I have specified GCC because the size
of bool types are a bit vague in the C standard.

regards,
dan carpenter

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-11-18  8:35 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-17 16:00 [PATCH 0/3] vc04_services: Promote bool usage Umang Jain
2022-11-17 16:00 ` Umang Jain
2022-11-17 16:00 ` [PATCH 1/3] Revert "staging: mmal-vchiq: Avoid use of bool in structures" Umang Jain
2022-11-17 16:00   ` Umang Jain
2022-11-17 16:09   ` Kieran Bingham
2022-11-17 16:09     ` Kieran Bingham
2022-11-17 17:55     ` Umang Jain
2022-11-17 17:55       ` Umang Jain
2022-11-17 18:02       ` Greg Kroah-Hartman
2022-11-17 18:02         ` Greg Kroah-Hartman
2022-11-17 18:22         ` Umang Jain
2022-11-17 18:22           ` Umang Jain
2022-11-18  0:12           ` Andrew Lunn
2022-11-18  0:12             ` Andrew Lunn
2022-11-18  3:58             ` Umang Jain
2022-11-18  3:58               ` Umang Jain
2022-11-18  8:35             ` Dan Carpenter [this message]
2022-11-18  8:35               ` Dan Carpenter
2022-11-17 16:00 ` [PATCH 2/3] vc04_services: mmal-vchiq: Use bool for vchiq_mmal_component.in_use Umang Jain
2022-11-17 16:00   ` Umang Jain
2022-11-18  0:23   ` Andrew Lunn
2022-11-18  0:23     ` Andrew Lunn
2022-11-18  9:01     ` Dan Carpenter
2022-11-18  9:01       ` Dan Carpenter
2022-11-17 16:00 ` [PATCH 3/3] vc04_services: bcm2835-camera: Use bool values for mmal_fmt.remove_padding Umang Jain
2022-11-17 16:00   ` Umang Jain
2022-11-17 18:11 ` [PATCH 0/3] vc04_services: Promote bool usage Stefan Wahren
2022-11-17 18:11   ` Stefan Wahren
2022-11-18  8:47   ` Dan Carpenter
2022-11-18  8:47     ` Dan Carpenter
2022-11-18 17:25   ` Dave Stevenson
2022-11-18 17:25     ` Dave Stevenson

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