Messages in this thread | | | Date | Wed, 13 Jul 2016 23:25:30 +0100 | From | Luis de Bethencourt <> | Subject | Re: [RFC PATCH] dynamic_debug: only add header when used |
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On 13/07/16 21:32, Andrew Morton wrote: > On Wed, 13 Jul 2016 18:09:53 +0100 Luis de Bethencourt <luisbg@osg.samsung.com> wrote: > >> kernel.h header doesn't directly use dynamic debug, instead we can include >> it in module.c (which used it via kernel.h). printk.h only uses it if >> CONFIG_DYNAMIC_DEBUG is on, changing the inclusion to only happen in that >> case. >> >> Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> >> --- >> Hi, >> >> While studying the problem that surfaced when adding #include <linux/kernel.h> >> in include/linux/string.h to have access to the MAX_SIZE macro [0]. I noticed >> that dynamic_debug.h is included in kernel.h even though it isn't necessary. >> Which in the case of adding kernel.h to string.h would mean a circular >> dependency. >> >> Not entirely sure if there is a reason for this beyond making dynamic debug >> available to module.c. Which is why I am sending this patch as an RFC. > > It would be good if we can do this. > > What is it in kernel.h that requires dynamic_debug.h? I tried your > patch along with > > --- a/kernel/module.c~dynamic_debug-only-add-header-when-used-fix > +++ a/kernel/module.c > @@ -60,7 +60,6 @@ > #include <linux/jump_label.h> > #include <linux/pfn.h> > #include <linux/bsearch.h> > -#include <linux/dynamic_debug.h> > #include <uapi/linux/module.h> > #include "module-internal.h" > > and module.o builds OK. >
Hi Andrew,
Replying to why dynamic_debug.h is needed in module.c, which I didn't explain before since I wanted to double-check.
kernel/module.c only needs dynamic_debug.h when CONFIG_DYNAMIC_DEBUG is not set. Which is probably why you could build it in your side.
If you deactivate that config you get an error in the two uses of ddebug_remove_module and one for ddebug_dyndbg_module_param_cb().
For example: ------------------------------------------------------ kernel/module.c: In function ‘free_module’: kernel/module.c:2080:2: error: implicit declaration of function ‘ddebug_remove_module’ [-Werror=implicit-function-declaration] ddebug_remove_module(mod->name); ------------------------------------------------------
By the way, since you added my patch in your -mm tree I resent with you listed as Signed-off-by, I hope that is OK. Let me know if it isn't for the future.
Thanks :) Luis
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