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Groups > linux.kernel > #1430466 > unrolled thread
| Started by | Borislav Petkov <bp@alien8.de> |
|---|---|
| First post | 2016-06-24 10:40 +0200 |
| Last post | 2016-06-27 11:20 +0200 |
| Articles | 4 — 2 participants |
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[PATCH 2/3] printk: Make the printk*once() variants return a value Borislav Petkov <bp@alien8.de> - 2016-06-24 10:40 +0200
Re: [PATCH 2/3] printk: Make the printk*once() variants return a value Joe Perches <joe@perches.com> - 2016-06-24 15:50 +0200
Re: [PATCH 2/3] printk: Make the printk*once() variants return a value Borislav Petkov <bp@alien8.de> - 2016-06-25 13:10 +0200
[PATCH -v2 2/3] printk: Make the printk*once() variants return a value Borislav Petkov <bp@alien8.de> - 2016-06-27 11:20 +0200
| From | Borislav Petkov <bp@alien8.de> |
|---|---|
| Date | 2016-06-24 10:40 +0200 |
| Subject | [PATCH 2/3] printk: Make the printk*once() variants return a value |
| Message-ID | <rNuOB-5IF-17@gated-at.bofh.it> |
From: Borislav Petkov <bp@suse.de>
Have printk*once() return a bool which denotes whether the string was
printed or not so that calling code can react accordingly.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/printk.h | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index f4da695fd615..464fcdddb359 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,11 +108,14 @@ struct va_format {
* Dummy printk for disabled debugging statements to use whilst maintaining
* gcc's format checking.
*/
-#define no_printk(fmt, ...) \
-do { \
- if (0) \
- printk(fmt, ##__VA_ARGS__); \
-} while (0)
+#define no_printk(fmt, ...) \
+({ \
+ do { \
+ if (0) \
+ printk(fmt, ##__VA_ARGS__); \
+ } while (0); \
+ 0; \
+})
#ifdef CONFIG_EARLY_PRINTK
extern asmlinkage __printf(1, 2)
@@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
#define printk_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk(fmt, ##__VA_ARGS__); \
} \
+ __ret_print_once; \
})
#define printk_deferred_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk_deferred(fmt, ##__VA_ARGS__); \
} \
+ __ret_print_once; \
})
#else
#define printk_once(fmt, ...) \
--
2.8.4
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| From | Joe Perches <joe@perches.com> |
|---|---|
| Date | 2016-06-24 15:50 +0200 |
| Subject | Re: [PATCH 2/3] printk: Make the printk*once() variants return a value |
| Message-ID | <rNzEC-h8-33@gated-at.bofh.it> |
| In reply to | #1430466 |
On Fri, 2016-06-24 at 10:30 +0200, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> Have printk*once() return a bool which denotes whether the string was
> printed or not so that calling code can react accordingly.
I expected object size to either increase or stay the
same with just this change.
Oddly, at least with gcc 5.3, some defconfig x86-64
objects _decrease_ in size.
for example: drivers/gpu/drm/i915/intel_opregion.o
I presume there's some curiosity in the gcc optimizer
with the evaluation of statement expression macros that
don't return a value.
Perhaps the printk_once macros should end with
unlikely(__ret_print_once);
like the WARN_ONCE variants.
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> include/linux/printk.h | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/printk.h b/include/linux/printk.h
> index f4da695fd615..464fcdddb359 100644
> --- a/include/linux/printk.h
> +++ b/include/linux/printk.h
> @@ -108,11 +108,14 @@ struct va_format {
> * Dummy printk for disabled debugging statements to use whilst maintaining
> * gcc's format checking.
> */
> -#define no_printk(fmt, ...) \
> -do { \
> - if (0) \
> - printk(fmt, ##__VA_ARGS__); \
> -} while (0)
> +#define no_printk(fmt, ...) \
> +({ \
> + do { \
> + if (0) \
> + printk(fmt, ##__VA_ARGS__); \
> + } while (0); \
> + 0; \
> +})
>
> #ifdef CONFIG_EARLY_PRINTK
> extern asmlinkage __printf(1, 2)
> @@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
> #define printk_once(fmt, ...) \
> ({ \
> static bool __print_once __read_mostly; \
> + bool __ret_print_once = !__print_once; \
> \
> if (!__print_once) { \
> __print_once = true; \
> printk(fmt, ##__VA_ARGS__); \
> } \
> + __ret_print_once; \
> })
> #define printk_deferred_once(fmt, ...) \
> ({ \
> static bool __print_once __read_mostly; \
> + bool __ret_print_once = !__print_once; \
> \
> if (!__print_once) { \
> __print_once = true; \
> printk_deferred(fmt, ##__VA_ARGS__); \
> } \
> + __ret_print_once; \
> })
> #else
> #define printk_once(fmt, ...) \
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| From | Borislav Petkov <bp@alien8.de> |
|---|---|
| Date | 2016-06-25 13:10 +0200 |
| Subject | Re: [PATCH 2/3] printk: Make the printk*once() variants return a value |
| Message-ID | <rNTDj-4JZ-1@gated-at.bofh.it> |
| In reply to | #1430682 |
On Fri, Jun 24, 2016 at 06:43:04AM -0700, Joe Perches wrote:
> Perhaps the printk_once macros should end with
> unlikely(__ret_print_once);
> like the WARN_ONCE variants.
Done, thanks.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
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| From | Borislav Petkov <bp@alien8.de> |
|---|---|
| Date | 2016-06-27 11:20 +0200 |
| Subject | [PATCH -v2 2/3] printk: Make the printk*once() variants return a value |
| Message-ID | <rOARY-6GU-21@gated-at.bofh.it> |
| In reply to | #1431116 |
From: Borislav Petkov <bp@suse.de>
Date: Thu, 23 Jun 2016 10:41:30 +0200
Subject: [PATCH] printk: Make the printk*once() variants return a value
Have printk*once() return a bool which denotes whether the string was
printed or not so that calling code can react accordingly.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
v2: Wrap __ret_print_once in unlikely.
include/linux/printk.h | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index f4da695fd615..f136b22c7772 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,11 +108,14 @@ struct va_format {
* Dummy printk for disabled debugging statements to use whilst maintaining
* gcc's format checking.
*/
-#define no_printk(fmt, ...) \
-do { \
- if (0) \
- printk(fmt, ##__VA_ARGS__); \
-} while (0)
+#define no_printk(fmt, ...) \
+({ \
+ do { \
+ if (0) \
+ printk(fmt, ##__VA_ARGS__); \
+ } while (0); \
+ 0; \
+})
#ifdef CONFIG_EARLY_PRINTK
extern asmlinkage __printf(1, 2)
@@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
#define printk_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk(fmt, ##__VA_ARGS__); \
} \
+ unlikely(__ret_print_once); \
})
#define printk_deferred_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk_deferred(fmt, ##__VA_ARGS__); \
} \
+ unlikely(__ret_print_once); \
})
#else
#define printk_once(fmt, ...) \
--
2.8.4
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
--
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