[PATCH 00/17] mark const init data with __initconst instead of __initdata

[PATCH 00/17] mark const init data with __initconst instead of __initdata

[Uwe Kleine-König]

Hello,

this series fixes a common error to use __initdata to mark const
variables. Most of the time this works well enough to go unnoticed
(though I wonder why the linker doesn't warn about that).
Just try adding something like

	int something __initdata;

to one of the patched files and compile to see the error.

While touching these annotations I also corrected the position where it
was wrong to go between the variable name and the =.

Note this series is not compile tested.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[PATCH 15/17] mtd: mark const init data with __initconst instead of __initdata

[Uwe Kleine-König]

As long as there is no other non-const variable marked __initdata in the
same compilation unit it doesn't hurt. If there were one however
compilation would fail with

	error: $variablename causes a section type conflict

because a section containing const variables is marked read only and so
cannot contain non-const variables.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/maps/wr_sbc82xx_flash.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/maps/wr_sbc82xx_flash.c b/drivers/mtd/maps/wr_sbc82xx_flash.c
index aa7e0cb..4f6bf60 100644
--- a/drivers/mtd/maps/wr_sbc82xx_flash.c
+++ b/drivers/mtd/maps/wr_sbc82xx_flash.c
@@ -59,7 +59,7 @@ static struct mtd_partition bigflash_parts[] = {
 	}
 };
 
-static const char *part_probes[] __initdata = {"cmdlinepart", "RedBoot", NULL};
+static const char *part_probes[] __initconst = {"cmdlinepart", "RedBoot", NULL};
 
 #define init_sbc82xx_one_flash(map, br, or)			\
 do {								\
-- 
1.7.9.1

Re: [PATCH 00/17] mark const init data with __initconst instead of __initdata

[Uwe Kleine-König]

On Thu, Mar 29, 2012 at 11:11:31PM +0200, Uwe Kleine-König wrote:
> Hello,
> 
> this series fixes a common error to use __initdata to mark const
> variables. Most of the time this works well enough to go unnoticed
> (though I wonder why the linker doesn't warn about that).
> Just try adding something like
> 
> 	int something __initdata;
> 
> to one of the patched files and compile to see the error.
> 
> While touching these annotations I also corrected the position where it
> was wrong to go between the variable name and the =.
> 
> Note this series is not compile tested.
After a question by Shawn Guo I noticed that my command to do the changes
was to lax and changed things that must not be changed (at least not
with further care). Affected are lines like:

	static const char *at91_dt_board_compat[] __initconst = {

While at91_dt_board_compat[0] is const, at91_dt_board_compat is not.

I will send a fixed series later today.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[PATCH v2 00/15] mark const init data with __initconst instead of __initdata

[Uwe Kleine-König]

Hello,

On Thu, Mar 29, 2012 at 11:11:31PM +0200, Uwe Kleine-König wrote:
> this series fixes a common error to use __initdata to mark const
> variables. Most of the time this works well enough to go unnoticed
> (though I wonder why the linker doesn't warn about that).
> Just try adding something like
> 
> 	int something __initdata;
> 
> to one of the patched files and compile to see the error.
> 
> While touching these annotations I also corrected the position where it
> was wrong to go between the variable name and the =.
> 
> Note this series is not compile tested.
I now dropped the wrong annotations. So two patches became obsolete
(mtd and percpu). Note that I also dropped fixing the position of
__initdata if changing it to __initconst was wrong. (I think if
__initdata is placed before the variable name it doesn't have any
effect.)

I didn't promote the Acks I got because all acked changes changed in v2.

For the details changed in each patch see the changelogs in the
respective patch mails that I follow up to this mail.

Thanks
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Re: [PATCH 15/17] mtd: mark const init data with __initconst instead of __initdata

[Artem Bityutskiy]

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On Thu, 2012-03-29 at 23:12 +0200, Uwe Kleine-König wrote:
> As long as there is no other non-const variable marked __initdata in the
> same compilation unit it doesn't hurt. If there were one however
> compilation would fail with
> 
> 	error: $variablename causes a section type conflict
> 

Pushed to l2-mtd.git, thanks!

-- 
Best Regards,
Artem Bityutskiy

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