Messages in this thread Patch in this message | | | Date | Wed, 20 Nov 2013 17:04:57 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 7/7] preempt: Take away preempt_enable_no_resched() from modules |
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Discourage drivers/modules to be creative with preemption.
Sadly all is implemented in macros and inline so if they want to do evil they still can, but at least try and discourage some.
Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Cc: rjw@rjwysocki.net Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com> Cc: Chris Leech <christopher.leech@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: hpa@zytor.com Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> --- include/linux/preempt.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
--- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -64,7 +64,11 @@ do { \ } while (0) #else -#define preempt_enable() preempt_enable_no_resched() +#define preempt_enable() \ +do { \ + barrier(); \ + preempt_count_dec(); \ +} while (0) #define preempt_check_resched() do { } while (0) #endif @@ -126,6 +130,16 @@ do { \ #define preempt_fold_need_resched() do { } while (0) #endif +#ifdef MODULE +/* + * Modules have no business playing preemption tricks. + */ +#undef sched_preempt_enable_no_resched +#undef preempt_enable_no_resched +#undef preempt_enable_no_resched_notrace +#undef preempt_check_resched +#endif + #ifdef CONFIG_PREEMPT_NOTIFIERS struct preempt_notifier;
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