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62 lines
1.1 KiB
62 lines
1.1 KiB
#ifndef _LINUX_BLOCKGROUP_LOCK_H |
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#define _LINUX_BLOCKGROUP_LOCK_H |
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/* |
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* Per-blockgroup locking for ext2 and ext3. |
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* |
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* Simple hashed spinlocking. |
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*/ |
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#include <linux/spinlock.h> |
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#include <linux/cache.h> |
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#ifdef CONFIG_SMP |
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/* |
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* We want a power-of-two. Is there a better way than this? |
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*/ |
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#if NR_CPUS >= 32 |
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#define NR_BG_LOCKS 128 |
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#elif NR_CPUS >= 16 |
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#define NR_BG_LOCKS 64 |
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#elif NR_CPUS >= 8 |
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#define NR_BG_LOCKS 32 |
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#elif NR_CPUS >= 4 |
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#define NR_BG_LOCKS 16 |
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#elif NR_CPUS >= 2 |
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#define NR_BG_LOCKS 8 |
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#else |
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#define NR_BG_LOCKS 4 |
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#endif |
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#else /* CONFIG_SMP */ |
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#define NR_BG_LOCKS 1 |
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#endif /* CONFIG_SMP */ |
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struct bgl_lock { |
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spinlock_t lock; |
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} ____cacheline_aligned_in_smp; |
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struct blockgroup_lock { |
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struct bgl_lock locks[NR_BG_LOCKS]; |
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}; |
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static inline void bgl_lock_init(struct blockgroup_lock *bgl) |
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{ |
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int i; |
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for (i = 0; i < NR_BG_LOCKS; i++) |
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spin_lock_init(&bgl->locks[i].lock); |
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} |
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/* |
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* The accessor is a macro so we can embed a blockgroup_lock into different |
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* superblock types |
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*/ |
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static inline spinlock_t * |
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bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group) |
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{ |
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return &bgl->locks[(block_group) & (NR_BG_LOCKS-1)].lock; |
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} |
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#endif
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