From 6de5bd128d381ad88ac6d419a5e597048eb468cf Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 11 Sep 2010 18:00:57 +0200 Subject: BKL: introduce CONFIG_BKL. With all the patches we have queued in the BKL removal tree, only a few dozen modules are left that actually rely on the BKL, and even there are lots of low-hanging fruit. We need to decide what to do about them, this patch illustrates one of the options: Every user of the BKL is marked as 'depends on BKL' in Kconfig, and the CONFIG_BKL becomes a user-visible option. If it gets disabled, no BKL using module can be built any more and the BKL code itself is compiled out. The one exception is file locking, which is practically always enabled and does a 'select BKL' instead. This effectively forces CONFIG_BKL to be enabled until we have solved the fs/lockd mess and can apply the patch that removes the BKL from fs/locks.c. Signed-off-by: Arnd Bergmann --- include/linux/smp_lock.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux/smp_lock.h') diff --git a/include/linux/smp_lock.h b/include/linux/smp_lock.h index 2ea1dd1ba21c..291f721144c2 100644 --- a/include/linux/smp_lock.h +++ b/include/linux/smp_lock.h @@ -54,12 +54,15 @@ static inline void cycle_kernel_lock(void) #else +#ifdef CONFIG_BKL /* provoke build bug if not set */ #define lock_kernel() #define unlock_kernel() -#define release_kernel_lock(task) do { } while(0) #define cycle_kernel_lock() do { } while(0) -#define reacquire_kernel_lock(task) 0 #define kernel_locked() 1 +#endif /* CONFIG_BKL */ + +#define release_kernel_lock(task) do { } while(0) +#define reacquire_kernel_lock(task) 0 #endif /* CONFIG_LOCK_KERNEL */ #endif /* __LINUX_SMPLOCK_H */ -- cgit v1.2.3 From 7957f0a857754c555e07f58a3fb83ac29501478c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 17 Nov 2010 14:58:36 -0800 Subject: Fix build failure due to hwirq.h needing smp_lock.h Arnd Bergmann did an automated scripting run to find left-over instances of , and had made it trigger it on the normal BKL use of lock_kernel and unlock_lernel (and apparently release_kernel_lock and reacquire_kernel_lock too, used by the scheduler). That resulted in commit 451a3c24b013 ("BKL: remove extraneous #include "). However, hardirq.h was the only remaining user of the old 'kernel_locked()' interface, and Arnd's script hadn't checked for that. So depending on your configuration and what header files had been included, you would get errors like "implicit declaration of function 'kernel_locked'" during the build. The right fix is not to just re-instate the smp_lock.h include - it is to just remove 'kernel_locked()' entirely, since the only use was this one special low-level detail. Just make hardirq.h do it directly. In fact this simplifies and clarifies the code, because some trivial analysis makes it clear that hardirq.h only ever used _one_ of the two definitions of kernel_locked(), so we can remove the other one entirely. Reported-by: Zimny Lech Reported-and-acked-by: Randy Dunlap Acked-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- include/linux/hardirq.h | 2 +- include/linux/smp_lock.h | 3 --- 2 files changed, 1 insertion(+), 4 deletions(-) (limited to 'include/linux/smp_lock.h') diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 8f3f467c57c6..bea1612d8f5c 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -96,7 +96,7 @@ #define in_nmi() (preempt_count() & NMI_MASK) #if defined(CONFIG_PREEMPT) && defined(CONFIG_BKL) -# define PREEMPT_INATOMIC_BASE kernel_locked() +# define PREEMPT_INATOMIC_BASE (current->lock_depth >= 0) #else # define PREEMPT_INATOMIC_BASE 0 #endif diff --git a/include/linux/smp_lock.h b/include/linux/smp_lock.h index 291f721144c2..3a1988202731 100644 --- a/include/linux/smp_lock.h +++ b/include/linux/smp_lock.h @@ -4,8 +4,6 @@ #ifdef CONFIG_LOCK_KERNEL #include -#define kernel_locked() (current->lock_depth >= 0) - extern int __lockfunc __reacquire_kernel_lock(void); extern void __lockfunc __release_kernel_lock(void); @@ -58,7 +56,6 @@ static inline void cycle_kernel_lock(void) #define lock_kernel() #define unlock_kernel() #define cycle_kernel_lock() do { } while(0) -#define kernel_locked() 1 #endif /* CONFIG_BKL */ #define release_kernel_lock(task) do { } while(0) -- cgit v1.2.3