Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com --- include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
void kunit_cleanup(struct kunit *test);
+#ifdef CONFIG_PRINTK void __printf(3, 4) kunit_printk(const char *level, const struct kunit *test, const char *fmt, ...); +#else +static inline void __printf(3, 4) kunit_printk(const char *level, + const struct kunit *test, + const char *fmt, ...) +{} +#endif
/** * kunit_info() - Prints an INFO level message associated with @test. diff --git a/kunit/test.c b/kunit/test.c index b2ca9b94c353..0aa1caf07a6b 100644 --- a/kunit/test.c +++ b/kunit/test.c @@ -16,6 +16,7 @@ static void kunit_set_failure(struct kunit *test) WRITE_ONCE(test->success, false); }
+#ifdef CONFIG_PRINTK static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); @@ -40,6 +41,29 @@ static void kunit_vprintk(const struct kunit *test, kunit_printk_emit(level[1] - '0', "\t# %s: %pV", test->name, vaf); }
+void kunit_printk(const char *level, + const struct kunit *test, + const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + kunit_vprintk(test, level, &vaf); + + va_end(args); +} +#else /* CONFIG_PRINTK */ +static inline int kunit_printk_emit(int level, const char *fmt, ...) +{ + return 0; +} +#endif /* CONFIG_PRINTK */ + static void kunit_print_tap_version(void) { static bool kunit_has_printed_tap_version; @@ -504,20 +528,3 @@ void kunit_cleanup(struct kunit *test) kunit_resource_free(test, resource); } } - -void kunit_printk(const char *level, - const struct kunit *test, - const char *fmt, ...) -{ - struct va_format vaf; - va_list args; - - va_start(args, fmt); - - vaf.fmt = fmt; - vaf.va = &args; - - kunit_vprintk(test, level, &vaf); - - va_end(args); -}
On 8/27/19 10:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
Acked-by: Randy Dunlap rdunlap@infradead.org # build-tested
Thanks.
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp) void kunit_cleanup(struct kunit *test); +#ifdef CONFIG_PRINTK
Please make this #if defined(CONFIG_PRINTK)
void __printf(3, 4) kunit_printk(const char *level,
Line these two up with const char *level,
const struct kunit *test, const char *fmt, ...);+#else +static inline void __printf(3, 4) kunit_printk(const char *level,
const struct kunit *test,const char *fmt, ...)
Same here.
+{}
Either line this up or make it
const char *fmt, ...) { }
It is hard to read the way it is currently indented.
+#endif /**
- kunit_info() - Prints an INFO level message associated with @test.
diff --git a/kunit/test.c b/kunit/test.c index b2ca9b94c353..0aa1caf07a6b 100644 --- a/kunit/test.c +++ b/kunit/test.c @@ -16,6 +16,7 @@ static void kunit_set_failure(struct kunit *test) WRITE_ONCE(test->success, false); } +#ifdef CONFIG_PRINTK
Same here - if defined
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); @@ -40,6 +41,29 @@ static void kunit_vprintk(const struct kunit *test, kunit_printk_emit(level[1] - '0', "\t# %s: %pV", test->name, vaf); } +void kunit_printk(const char *level,
const struct kunit *test,const char *fmt, ...)
Line the arguments up.
+{
- struct va_format vaf;
- va_list args;
- va_start(args, fmt);
- vaf.fmt = fmt;
- vaf.va = &args;
- kunit_vprintk(test, level, &vaf);
- va_end(args);
+} +#else /* CONFIG_PRINTK */ +static inline int kunit_printk_emit(int level, const char *fmt, ...) +{
- return 0;
Is there a reason to not use
+} > +#endif /* CONFIG_PRINTK */
- static void kunit_print_tap_version(void) { static bool kunit_has_printed_tap_version;
@@ -504,20 +528,3 @@ void kunit_cleanup(struct kunit *test) kunit_resource_free(test, resource); } }
-void kunit_printk(const char *level,
const struct kunit *test,const char *fmt, ...) > -{- struct va_format vaf;
- va_list args;
- va_start(args, fmt);
- vaf.fmt = fmt;
- vaf.va = &args;
- kunit_vprintk(test, level, &vaf);
- va_end(args);
-}
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
thanks, -- Shuah
On 8/27/19 1:21 PM, shuah wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp) void kunit_cleanup(struct kunit *test); +#ifdef CONFIG_PRINTK
Please make this #if defined(CONFIG_PRINTK)
explain why, please?
thanks.
On 8/27/19 2:53 PM, Randy Dunlap wrote:
On 8/27/19 1:21 PM, shuah wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp) void kunit_cleanup(struct kunit *test); +#ifdef CONFIG_PRINTK
Please make this #if defined(CONFIG_PRINTK)
explain why, please?
thanks.
This can be used to do compound logic. I have been using this style for that reason starting a couple of years now. I seem to work in code paths where I have to look for multiple config vars.
In this case, it probably doesn't matter as much either way.
thanks, -- Shuah
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with printk.
So it appears that we have to weigh the following trade-offs:
Using vprintk_emit:
Pros: - That's what dev_printk uses. - No checkpatch warnings.
Cons: - Harder to maintain (requires ifdefery).
Using printk:
Pros: - Easier to maintain.
Cons: - I am less confident that it is correct (I am not 100% certain that printk is intended to be used this way). - Checkpatch warnings. - Extra layer of string formatting.
My preference is to go the vprintk_emit route since I am more confident that it is right, but I don't have a strong preference.
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
I am not asking you to use printk() in place of vprintk_emit(). It is perfectly fine to use vprintk_emit()
So it appears that we have to weigh the following trade-offs:
Using vprintk_emit:
Pros:
- That's what dev_printk uses.
Not sure what you mean by this. I am suggesting if you can just call vprintk_emit() and include printk.h and not have to ifdef around all the other callers of kunit_vprintk_emit()
Yes. There is the other issue of why do you need the complexity of having kunit_vprintk_emit() at all.
thanks, -- Shuah
On Tue, Aug 27, 2019 at 3:00 PM shuah shuah@kernel.org wrote:
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote:
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/test.h | 7 +++++++ kunit/test.c | 41 ++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index 8b7eb03d4971..339af5f95c4a 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
Ah sorry, I misunderstood you.
No, that doesn't work. I tried including linux/printk.h, and I get the same error.
The reason for this is that vprintk_emit() is only defined when CONFIG_PRINTK=y:
https://elixir.bootlin.com/linux/latest/ident/vprintk_emit
I am not asking you to use printk() in place of vprintk_emit(). It is perfectly fine to use vprintk_emit()
Okay, cool.
So it appears that we have to weigh the following trade-offs:
Using vprintk_emit:
Pros:
- That's what dev_printk uses.
Not sure what you mean by this. I am suggesting if you can just call vprintk_emit() and include printk.h and not have to ifdef around all the other callers of kunit_vprintk_emit()
Oh, I was just saying that I heavily based my implementation of kunit_printk on dev_printk. So I have a high degree of confidence that it is okay to use it the way that I am using it.
Yes. There is the other issue of why do you need the complexity of having kunit_vprintk_emit() at all.
Right, and the problem with the alternative, is there is no good kernel API for logging with the log level set dynamically. printk prefers to have it as a string prefix on the format string, but I cannot do that because I need to add my own prefix to the format string.
So, I guess I should just go ahead and address the earlier comments on this patch?
-----Original Message----- From: Brendan Higgins
On Tue, Aug 27, 2019 at 3:00 PM shuah shuah@kernel.org wrote:
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote: > Previously KUnit assumed that printk would always be present,
which is
> not a valid assumption to make. Fix that by ifdefing out functions
which
> directly depend on printk core functions similar to what dev_printk > does. > > Reported-by: Randy Dunlap rdunlap@infradead.org > Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-
715a-fabe016259df@kernel.org/T/#t
> Cc: Stephen Rothwell sfr@canb.auug.org.au > Signed-off-by: Brendan Higgins brendanhiggins@google.com > --- > include/kunit/test.h | 7 +++++++ > kunit/test.c | 41 ++++++++++++++++++++++++----------------- > 2 files changed, 31 insertions(+), 17 deletions(-) > > diff --git a/include/kunit/test.h b/include/kunit/test.h > index 8b7eb03d4971..339af5f95c4a 100644 > --- a/include/kunit/test.h > +++ b/include/kunit/test.h > @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit
*test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by
including
printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage",
KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with
printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
Ah sorry, I misunderstood you.
No, that doesn't work. I tried including linux/printk.h, and I get the same error.
The reason for this is that vprintk_emit() is only defined when CONFIG_PRINTK=y:
Ugh. That's just a bug in include/linux/printk.h
There should be a stub definition for vprintk_emit() in the #else part of #ifdef CONFIG_PRINTK.
You shouldn't be dealing with whether printk is present or not in the kunit code. All the printk-related routines are supposed to evaporate themselves, based on the conditional in include/linux/printk.h
That should be fixed there instead of in your code.
Let me know if you'd like me to submit a patch for that. I only hesitate because your patch depends on it, and IMHO it makes more sense to include it in your batch than separately. Otherwise there's a patch race condition. -- Tim
On Tue, Aug 27, 2019 at 3:38 PM Tim.Bird@sony.com wrote:
-----Original Message----- From: Brendan Higgins
On Tue, Aug 27, 2019 at 3:00 PM shuah shuah@kernel.org wrote:
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote: > > On 8/27/19 11:49 AM, Brendan Higgins wrote: >> Previously KUnit assumed that printk would always be present,
which is
>> not a valid assumption to make. Fix that by ifdefing out functions
which
>> directly depend on printk core functions similar to what dev_printk >> does. >> >> Reported-by: Randy Dunlap rdunlap@infradead.org >> Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-
715a-fabe016259df@kernel.org/T/#t
>> Cc: Stephen Rothwell sfr@canb.auug.org.au >> Signed-off-by: Brendan Higgins brendanhiggins@google.com >> --- >> include/kunit/test.h | 7 +++++++ >> kunit/test.c | 41 ++++++++++++++++++++++++----------------- >> 2 files changed, 31 insertions(+), 17 deletions(-) >> >> diff --git a/include/kunit/test.h b/include/kunit/test.h >> index 8b7eb03d4971..339af5f95c4a 100644 >> --- a/include/kunit/test.h >> +++ b/include/kunit/test.h >> @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit
*test, size_t size, gfp_t gfp)
[...] > Okay after reviewing this, I am not sure why you need to do all > this. > > Why can't you just change the root function that throws the warn: > > static int kunit_vprintk_emit(int level, const char *fmt, va_list args) > { > return vprintk_emit(0, level, NULL, 0, fmt, args); > } > > You aren'r really doing anything extra here, other than calling > vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
> Unless I am missing something, can't you solve this problem by
including
> printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage",
KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with
printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
Ah sorry, I misunderstood you.
No, that doesn't work. I tried including linux/printk.h, and I get the same error.
The reason for this is that vprintk_emit() is only defined when CONFIG_PRINTK=y:
Ugh. That's just a bug in include/linux/printk.h
There should be a stub definition for vprintk_emit() in the #else part of #ifdef CONFIG_PRINTK.
You shouldn't be dealing with whether printk is present or not in the kunit code. All the printk-related routines are supposed to evaporate themselves, based on the conditional in include/linux/printk.h
That should be fixed there instead of in your code.
Alright. That makes sense.
I will submit a patch to fix it.
Sorry for not suggesting that, I just assumed that it was my mistake in how I was using printk.
Let me know if you'd like me to submit a patch for that. I only hesitate because your patch depends on it, and IMHO it makes more sense to include it in your batch than separately. Otherwise there's a patch race condition.
Thanks for clearing up the confusion!
On 8/27/19 4:16 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 3:00 PM shuah shuah@kernel.org wrote:
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote:
On 8/27/19 11:49 AM, Brendan Higgins wrote: > Previously KUnit assumed that printk would always be present, which is > not a valid assumption to make. Fix that by ifdefing out functions which > directly depend on printk core functions similar to what dev_printk > does. > > Reported-by: Randy Dunlap rdunlap@infradead.org > Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... > Cc: Stephen Rothwell sfr@canb.auug.org.au > Signed-off-by: Brendan Higgins brendanhiggins@google.com > --- > include/kunit/test.h | 7 +++++++ > kunit/test.c | 41 ++++++++++++++++++++++++----------------- > 2 files changed, 31 insertions(+), 17 deletions(-) > > diff --git a/include/kunit/test.h b/include/kunit/test.h > index 8b7eb03d4971..339af5f95c4a 100644 > --- a/include/kunit/test.h > +++ b/include/kunit/test.h > @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
[...]
Okay after reviewing this, I am not sure why you need to do all this.
Why can't you just change the root function that throws the warn:
static int kunit_vprintk_emit(int level, const char *fmt, va_list args){ return vprintk_emit(0, level, NULL, 0, fmt, args); }
You aren'r really doing anything extra here, other than calling vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
Unless I am missing something, can't you solve this problem by including printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
Ah sorry, I misunderstood you.
No, that doesn't work. I tried including linux/printk.h, and I get the same error.
The reason for this is that vprintk_emit() is only defined when CONFIG_PRINTK=y:
This is the real problem here. printk.h defines several for !CONFIG_PRINTK case.
https://elixir.bootlin.com/linux/latest/ident/vprintk_emit
I am not asking you to use printk() in place of vprintk_emit(). It is perfectly fine to use vprintk_emit()
Okay, cool.
So it appears that we have to weigh the following trade-offs:
Using vprintk_emit:
Pros:
- That's what dev_printk uses.
Not sure what you mean by this. I am suggesting if you can just call vprintk_emit() and include printk.h and not have to ifdef around all the other callers of kunit_vprintk_emit()
Oh, I was just saying that I heavily based my implementation of kunit_printk on dev_printk. So I have a high degree of confidence that it is okay to use it the way that I am using it.
Yes. There is the other issue of why do you need the complexity of having kunit_vprintk_emit() at all.
Right, and the problem with the alternative, is there is no good kernel API for logging with the log level set dynamically. printk prefers to have it as a string prefix on the format string, but I cannot do that because I need to add my own prefix to the format string.
So, I guess I should just go ahead and address the earlier comments on this patch?
So what does your code do in the case of !CONFIG_PRINTK. From my read of it, it returns 0 from kunit_printk_emit(0 from my read of it. What I am saying is this is a lot of indirection instead of fixing the leaf function which is kunit_vprintk_emit().
+#else /* CONFIG_PRINTK */ +static inline int kunit_printk_emit(int level, const char *fmt, ...) +{ + return 0; +} +#endif /* CONFIG_PRINTK */
Does the following work?
#if defined CONFIG_PRINTK static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); } #else static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return 0; } #endif
I think the real problem is in the printk.h with its missing define for vprintk_emit() for !CONFIG_PRINTK case. There seem to only one call for this in drivers/base/core.c in CONFIG_PRINTK path. Unless I am totally missing some context for why there is no stub for vprintk_emit() for !CONFIG_PRINTK case
thanks, -- Shuah
On Tue, Aug 27, 2019 at 3:55 PM shuah shuah@kernel.org wrote:
On 8/27/19 4:16 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 3:00 PM shuah shuah@kernel.org wrote:
On 8/27/19 3:36 PM, Brendan Higgins wrote:
On Tue, Aug 27, 2019 at 2:09 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 2:03 PM Brendan Higgins brendanhiggins@google.com wrote:
On Tue, Aug 27, 2019 at 1:21 PM shuah shuah@kernel.org wrote: > > On 8/27/19 11:49 AM, Brendan Higgins wrote: >> Previously KUnit assumed that printk would always be present, which is >> not a valid assumption to make. Fix that by ifdefing out functions which >> directly depend on printk core functions similar to what dev_printk >> does. >> >> Reported-by: Randy Dunlap rdunlap@infradead.org >> Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... >> Cc: Stephen Rothwell sfr@canb.auug.org.au >> Signed-off-by: Brendan Higgins brendanhiggins@google.com >> --- >> include/kunit/test.h | 7 +++++++ >> kunit/test.c | 41 ++++++++++++++++++++++++----------------- >> 2 files changed, 31 insertions(+), 17 deletions(-) >> >> diff --git a/include/kunit/test.h b/include/kunit/test.h >> index 8b7eb03d4971..339af5f95c4a 100644 >> --- a/include/kunit/test.h >> +++ b/include/kunit/test.h >> @@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp) [...] > Okay after reviewing this, I am not sure why you need to do all > this. > > Why can't you just change the root function that throws the warn: > > static int kunit_vprintk_emit(int level, const char *fmt, va_list args) > { > return vprintk_emit(0, level, NULL, 0, fmt, args); > } > > You aren'r really doing anything extra here, other than calling > vprintk_emit()
Yeah, I did that a while ago. I think it was a combination of trying to avoid an extra layer of adding and then removing the log level, and that's what dev_printk and friends did.
But I think you are probably right. It's a lot of maintenance overhead to get rid of that. Probably best to just use what the printk people have.
> Unless I am missing something, can't you solve this problem by including > printk.h and let it handle the !CONFIG_PRINTK case?
Randy, I hope you don't mind, but I am going to ask you to re-ack my next revision since it basically addresses the problem in a totally different way.
Actually, scratch that. Checkpatch doesn't like me calling printk without using a KERN_<LEVEL>.
Now that I am thinking back to when I wrote this. I think it also might not like using a dynamic KERN_<LEVEL> either (printk("%s my message", KERN_INFO)).
I am going to have to do some more investigation.
Alright, I am pretty sure it is safe to do printk("%smessage", KERN_<LEVEL>);
Looking at the printk implementation, it appears to do the format before it checks the log level:
https://elixir.bootlin.com/linux/v5.2.10/source/kernel/printk/printk.c#L1907
So I am pretty sure we can do it either with the vprintk_emit or with printk.
Let me see if we are on the same page first. I am asking if you can just include printk.h for vprintk_emit() define for both CONFIG_PRINTK and !CONFIG_PRINTK cases.
Ah sorry, I misunderstood you.
No, that doesn't work. I tried including linux/printk.h, and I get the same error.
The reason for this is that vprintk_emit() is only defined when CONFIG_PRINTK=y:
This is the real problem here. printk.h defines several for !CONFIG_PRINTK case.
Yeah, Tim pointed that out.
I think both of you are right, I should be filing my fix against them.
https://elixir.bootlin.com/linux/latest/ident/vprintk_emit
I am not asking you to use printk() in place of vprintk_emit(). It is perfectly fine to use vprintk_emit()
Okay, cool.
So it appears that we have to weigh the following trade-offs:
Using vprintk_emit:
Pros:
- That's what dev_printk uses.
Not sure what you mean by this. I am suggesting if you can just call vprintk_emit() and include printk.h and not have to ifdef around all the other callers of kunit_vprintk_emit()
Oh, I was just saying that I heavily based my implementation of kunit_printk on dev_printk. So I have a high degree of confidence that it is okay to use it the way that I am using it.
Yes. There is the other issue of why do you need the complexity of having kunit_vprintk_emit() at all.
Right, and the problem with the alternative, is there is no good kernel API for logging with the log level set dynamically. printk prefers to have it as a string prefix on the format string, but I cannot do that because I need to add my own prefix to the format string.
So, I guess I should just go ahead and address the earlier comments on this patch?
So what does your code do in the case of !CONFIG_PRINTK. From my read of it, it returns 0 from kunit_printk_emit(0 from my read of it. What I am saying is this is a lot of indirection instead of fixing the leaf function which is kunit_vprintk_emit().
Agreed. My apologies, as I mentioned in response to Tim, I just assumed I was using it wrong.
+#else /* CONFIG_PRINTK */ +static inline int kunit_printk_emit(int level, const char *fmt, ...) +{
return 0;+} +#endif /* CONFIG_PRINTK */
Does the following work?
#if defined CONFIG_PRINTK static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return vprintk_emit(0, level, NULL, 0, fmt, args); } #else static int kunit_vprintk_emit(int level, const char *fmt, va_list args) { return 0; } #endif
I think the real problem is in the printk.h with its missing define for vprintk_emit() for !CONFIG_PRINTK case. There seem to only one call for this in drivers/base/core.c in CONFIG_PRINTK path. Unless I am totally missing some context for why there is no stub for vprintk_emit() for !CONFIG_PRINTK case
Agreed.
Sorry again for the confusion.
Thanks!
Quoting Brendan Higgins (2019-08-27 10:49:32)
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
Does kunit itself have any meaning if printk doesn't work? Why not just depend on CONFIG_PRINTK for now?
On Tue, Aug 27, 2019 at 2:46 PM Stephen Boyd sboyd@kernel.org wrote:
Quoting Brendan Higgins (2019-08-27 10:49:32)
Previously KUnit assumed that printk would always be present, which is not a valid assumption to make. Fix that by ifdefing out functions which directly depend on printk core functions similar to what dev_printk does.
Reported-by: Randy Dunlap rdunlap@infradead.org Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df... Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Brendan Higgins brendanhiggins@google.com
Does kunit itself have any meaning if printk doesn't work? Why not just depend on CONFIG_PRINTK for now?
I was thinking about that, but I figured it is probably easier in the long run to make sure it always works without printk.
It also just seemed like the right thing to do, but I suppose that's not a very good reason.
I am fine with any of the three options: depend on CONFIG_PRINTK - as suggested by Stephen, just use printk - as suggested by Shuah, or continue to use vprintk_emit as I have been doing. However, my preference is the vprintk_emit option.
Anyone have any strong opinions on the matter?
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