[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-Ki? 1/2 nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 01/17] percpu: 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-KA?nig <u.kleine-koenig@pengutronix.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-mm@kvack.org
---
 mm/percpu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index f47af91..5e812f5 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1370,7 +1370,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 
 #ifdef CONFIG_SMP
 
-const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
+const char *pcpu_fc_names[PCPU_FC_NR] __initconst = {
 	[PCPU_FC_AUTO]	= "auto",
 	[PCPU_FC_EMBED]	= "embed",
 	[PCPU_FC_PAGE]	= "page",
-- 
1.7.9.1

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

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-Ki? 1/2 nig 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-Ki? 1/2 nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[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-Ki? 1/2 nig 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-Ki? 1/2 nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>