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6de5bd128d
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 <arnd@arndb.de>
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
#ifndef __LINUX_SMPLOCK_H
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#define __LINUX_SMPLOCK_H
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#ifdef CONFIG_LOCK_KERNEL
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#include <linux/sched.h>
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#define kernel_locked() (current->lock_depth >= 0)
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extern int __lockfunc __reacquire_kernel_lock(void);
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extern void __lockfunc __release_kernel_lock(void);
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/*
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* Release/re-acquire global kernel lock for the scheduler
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*/
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#define release_kernel_lock(tsk) do { \
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if (unlikely((tsk)->lock_depth >= 0)) \
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__release_kernel_lock(); \
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} while (0)
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static inline int reacquire_kernel_lock(struct task_struct *task)
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{
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if (unlikely(task->lock_depth >= 0))
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return __reacquire_kernel_lock();
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return 0;
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}
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extern void __lockfunc
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_lock_kernel(const char *func, const char *file, int line)
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__acquires(kernel_lock);
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extern void __lockfunc
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_unlock_kernel(const char *func, const char *file, int line)
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__releases(kernel_lock);
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#define lock_kernel() do { \
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_lock_kernel(__func__, __FILE__, __LINE__); \
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} while (0)
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#define unlock_kernel() do { \
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_unlock_kernel(__func__, __FILE__, __LINE__); \
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} while (0)
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/*
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* Various legacy drivers don't really need the BKL in a specific
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* function, but they *do* need to know that the BKL became available.
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* This function just avoids wrapping a bunch of lock/unlock pairs
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* around code which doesn't really need it.
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*/
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static inline void cycle_kernel_lock(void)
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{
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lock_kernel();
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unlock_kernel();
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}
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#else
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#ifdef CONFIG_BKL /* provoke build bug if not set */
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#define lock_kernel()
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#define unlock_kernel()
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#define cycle_kernel_lock() do { } while(0)
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#define kernel_locked() 1
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#endif /* CONFIG_BKL */
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#define release_kernel_lock(task) do { } while(0)
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#define reacquire_kernel_lock(task) 0
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#endif /* CONFIG_LOCK_KERNEL */
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#endif /* __LINUX_SMPLOCK_H */
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