Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
This commit is contained in:
Linus Torvalds
677
fs/mbcache.c
Normal file
677
fs/mbcache.c
Normal file
@@ -0,0 +1,677 @@
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/*
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* linux/fs/mbcache.c
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* (C) 2001-2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
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*/
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/*
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* Filesystem Meta Information Block Cache (mbcache)
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*
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* The mbcache caches blocks of block devices that need to be located
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* by their device/block number, as well as by other criteria (such
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* as the block's contents).
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*
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* There can only be one cache entry in a cache per device and block number.
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* Additional indexes need not be unique in this sense. The number of
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* additional indexes (=other criteria) can be hardwired at compile time
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* or specified at cache create time.
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*
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* Each cache entry is of fixed size. An entry may be `valid' or `invalid'
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* in the cache. A valid entry is in the main hash tables of the cache,
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* and may also be in the lru list. An invalid entry is not in any hashes
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* or lists.
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*
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* A valid cache entry is only in the lru list if no handles refer to it.
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* Invalid cache entries will be freed when the last handle to the cache
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* entry is released. Entries that cannot be freed immediately are put
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* back on the lru list.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/hash.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/mbcache.h>
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#ifdef MB_CACHE_DEBUG
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# define mb_debug(f...) do { \
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printk(KERN_DEBUG f); \
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printk("\n"); \
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} while (0)
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#define mb_assert(c) do { if (!(c)) \
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printk(KERN_ERR "assertion " #c " failed\n"); \
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} while(0)
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#else
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# define mb_debug(f...) do { } while(0)
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# define mb_assert(c) do { } while(0)
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#endif
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#define mb_error(f...) do { \
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printk(KERN_ERR f); \
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printk("\n"); \
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} while(0)
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#define MB_CACHE_WRITER ((unsigned short)~0U >> 1)
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DECLARE_WAIT_QUEUE_HEAD(mb_cache_queue);
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MODULE_AUTHOR("Andreas Gruenbacher <a.gruenbacher@computer.org>");
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MODULE_DESCRIPTION("Meta block cache (for extended attributes)");
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MODULE_LICENSE("GPL");
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EXPORT_SYMBOL(mb_cache_create);
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EXPORT_SYMBOL(mb_cache_shrink);
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EXPORT_SYMBOL(mb_cache_destroy);
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EXPORT_SYMBOL(mb_cache_entry_alloc);
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EXPORT_SYMBOL(mb_cache_entry_insert);
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EXPORT_SYMBOL(mb_cache_entry_release);
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EXPORT_SYMBOL(mb_cache_entry_free);
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EXPORT_SYMBOL(mb_cache_entry_get);
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#if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0)
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EXPORT_SYMBOL(mb_cache_entry_find_first);
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EXPORT_SYMBOL(mb_cache_entry_find_next);
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#endif
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struct mb_cache {
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struct list_head c_cache_list;
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const char *c_name;
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struct mb_cache_op c_op;
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atomic_t c_entry_count;
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int c_bucket_bits;
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#ifndef MB_CACHE_INDEXES_COUNT
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int c_indexes_count;
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#endif
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kmem_cache_t *c_entry_cache;
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struct list_head *c_block_hash;
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struct list_head *c_indexes_hash[0];
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};
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/*
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* Global data: list of all mbcache's, lru list, and a spinlock for
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* accessing cache data structures on SMP machines. The lru list is
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* global across all mbcaches.
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*/
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static LIST_HEAD(mb_cache_list);
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static LIST_HEAD(mb_cache_lru_list);
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static DEFINE_SPINLOCK(mb_cache_spinlock);
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static struct shrinker *mb_shrinker;
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static inline int
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mb_cache_indexes(struct mb_cache *cache)
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{
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#ifdef MB_CACHE_INDEXES_COUNT
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return MB_CACHE_INDEXES_COUNT;
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#else
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return cache->c_indexes_count;
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#endif
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}
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/*
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* What the mbcache registers as to get shrunk dynamically.
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*/
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static int mb_cache_shrink_fn(int nr_to_scan, unsigned int gfp_mask);
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static inline int
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__mb_cache_entry_is_hashed(struct mb_cache_entry *ce)
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{
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return !list_empty(&ce->e_block_list);
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}
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static inline void
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__mb_cache_entry_unhash(struct mb_cache_entry *ce)
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{
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int n;
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if (__mb_cache_entry_is_hashed(ce)) {
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list_del_init(&ce->e_block_list);
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for (n=0; n<mb_cache_indexes(ce->e_cache); n++)
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list_del(&ce->e_indexes[n].o_list);
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}
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}
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static inline void
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__mb_cache_entry_forget(struct mb_cache_entry *ce, int gfp_mask)
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{
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struct mb_cache *cache = ce->e_cache;
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mb_assert(!(ce->e_used || ce->e_queued));
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if (cache->c_op.free && cache->c_op.free(ce, gfp_mask)) {
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/* free failed -- put back on the lru list
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for freeing later. */
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spin_lock(&mb_cache_spinlock);
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list_add(&ce->e_lru_list, &mb_cache_lru_list);
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spin_unlock(&mb_cache_spinlock);
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} else {
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kmem_cache_free(cache->c_entry_cache, ce);
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atomic_dec(&cache->c_entry_count);
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}
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}
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static inline void
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__mb_cache_entry_release_unlock(struct mb_cache_entry *ce)
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{
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/* Wake up all processes queuing for this cache entry. */
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if (ce->e_queued)
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wake_up_all(&mb_cache_queue);
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if (ce->e_used >= MB_CACHE_WRITER)
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ce->e_used -= MB_CACHE_WRITER;
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ce->e_used--;
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if (!(ce->e_used || ce->e_queued)) {
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if (!__mb_cache_entry_is_hashed(ce))
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goto forget;
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mb_assert(list_empty(&ce->e_lru_list));
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list_add_tail(&ce->e_lru_list, &mb_cache_lru_list);
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}
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spin_unlock(&mb_cache_spinlock);
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return;
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forget:
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spin_unlock(&mb_cache_spinlock);
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__mb_cache_entry_forget(ce, GFP_KERNEL);
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}
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/*
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* mb_cache_shrink_fn() memory pressure callback
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*
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* This function is called by the kernel memory management when memory
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* gets low.
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*
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* @nr_to_scan: Number of objects to scan
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* @gfp_mask: (ignored)
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*
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* Returns the number of objects which are present in the cache.
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*/
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static int
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mb_cache_shrink_fn(int nr_to_scan, unsigned int gfp_mask)
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{
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LIST_HEAD(free_list);
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struct list_head *l, *ltmp;
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int count = 0;
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spin_lock(&mb_cache_spinlock);
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list_for_each(l, &mb_cache_list) {
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struct mb_cache *cache =
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list_entry(l, struct mb_cache, c_cache_list);
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mb_debug("cache %s (%d)", cache->c_name,
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atomic_read(&cache->c_entry_count));
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count += atomic_read(&cache->c_entry_count);
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}
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mb_debug("trying to free %d entries", nr_to_scan);
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if (nr_to_scan == 0) {
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spin_unlock(&mb_cache_spinlock);
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goto out;
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}
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while (nr_to_scan-- && !list_empty(&mb_cache_lru_list)) {
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struct mb_cache_entry *ce =
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list_entry(mb_cache_lru_list.next,
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struct mb_cache_entry, e_lru_list);
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list_move_tail(&ce->e_lru_list, &free_list);
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__mb_cache_entry_unhash(ce);
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}
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spin_unlock(&mb_cache_spinlock);
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list_for_each_safe(l, ltmp, &free_list) {
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__mb_cache_entry_forget(list_entry(l, struct mb_cache_entry,
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e_lru_list), gfp_mask);
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}
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out:
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return (count / 100) * sysctl_vfs_cache_pressure;
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}
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/*
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* mb_cache_create() create a new cache
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*
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* All entries in one cache are equal size. Cache entries may be from
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* multiple devices. If this is the first mbcache created, registers
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* the cache with kernel memory management. Returns NULL if no more
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* memory was available.
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*
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* @name: name of the cache (informal)
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* @cache_op: contains the callback called when freeing a cache entry
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* @entry_size: The size of a cache entry, including
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* struct mb_cache_entry
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* @indexes_count: number of additional indexes in the cache. Must equal
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* MB_CACHE_INDEXES_COUNT if the number of indexes is
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* hardwired.
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* @bucket_bits: log2(number of hash buckets)
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*/
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struct mb_cache *
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mb_cache_create(const char *name, struct mb_cache_op *cache_op,
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size_t entry_size, int indexes_count, int bucket_bits)
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{
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int m=0, n, bucket_count = 1 << bucket_bits;
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struct mb_cache *cache = NULL;
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if(entry_size < sizeof(struct mb_cache_entry) +
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indexes_count * sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]))
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return NULL;
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cache = kmalloc(sizeof(struct mb_cache) +
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indexes_count * sizeof(struct list_head), GFP_KERNEL);
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if (!cache)
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goto fail;
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cache->c_name = name;
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cache->c_op.free = NULL;
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if (cache_op)
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cache->c_op.free = cache_op->free;
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atomic_set(&cache->c_entry_count, 0);
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cache->c_bucket_bits = bucket_bits;
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#ifdef MB_CACHE_INDEXES_COUNT
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mb_assert(indexes_count == MB_CACHE_INDEXES_COUNT);
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#else
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cache->c_indexes_count = indexes_count;
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#endif
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cache->c_block_hash = kmalloc(bucket_count * sizeof(struct list_head),
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GFP_KERNEL);
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if (!cache->c_block_hash)
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goto fail;
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for (n=0; n<bucket_count; n++)
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INIT_LIST_HEAD(&cache->c_block_hash[n]);
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for (m=0; m<indexes_count; m++) {
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cache->c_indexes_hash[m] = kmalloc(bucket_count *
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sizeof(struct list_head),
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GFP_KERNEL);
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if (!cache->c_indexes_hash[m])
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goto fail;
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for (n=0; n<bucket_count; n++)
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INIT_LIST_HEAD(&cache->c_indexes_hash[m][n]);
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}
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cache->c_entry_cache = kmem_cache_create(name, entry_size, 0,
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SLAB_RECLAIM_ACCOUNT, NULL, NULL);
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if (!cache->c_entry_cache)
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goto fail;
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spin_lock(&mb_cache_spinlock);
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list_add(&cache->c_cache_list, &mb_cache_list);
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spin_unlock(&mb_cache_spinlock);
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return cache;
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fail:
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if (cache) {
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while (--m >= 0)
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kfree(cache->c_indexes_hash[m]);
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if (cache->c_block_hash)
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kfree(cache->c_block_hash);
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kfree(cache);
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}
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return NULL;
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}
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/*
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* mb_cache_shrink()
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*
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* Removes all cache entires of a device from the cache. All cache entries
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* currently in use cannot be freed, and thus remain in the cache. All others
|
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* are freed.
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||||
*
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||||
* @cache: which cache to shrink
|
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* @bdev: which device's cache entries to shrink
|
||||
*/
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void
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||||
mb_cache_shrink(struct mb_cache *cache, struct block_device *bdev)
|
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{
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LIST_HEAD(free_list);
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struct list_head *l, *ltmp;
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spin_lock(&mb_cache_spinlock);
|
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list_for_each_safe(l, ltmp, &mb_cache_lru_list) {
|
||||
struct mb_cache_entry *ce =
|
||||
list_entry(l, struct mb_cache_entry, e_lru_list);
|
||||
if (ce->e_bdev == bdev) {
|
||||
list_move_tail(&ce->e_lru_list, &free_list);
|
||||
__mb_cache_entry_unhash(ce);
|
||||
}
|
||||
}
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
list_for_each_safe(l, ltmp, &free_list) {
|
||||
__mb_cache_entry_forget(list_entry(l, struct mb_cache_entry,
|
||||
e_lru_list), GFP_KERNEL);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_destroy()
|
||||
*
|
||||
* Shrinks the cache to its minimum possible size (hopefully 0 entries),
|
||||
* and then destroys it. If this was the last mbcache, un-registers the
|
||||
* mbcache from kernel memory management.
|
||||
*/
|
||||
void
|
||||
mb_cache_destroy(struct mb_cache *cache)
|
||||
{
|
||||
LIST_HEAD(free_list);
|
||||
struct list_head *l, *ltmp;
|
||||
int n;
|
||||
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
list_for_each_safe(l, ltmp, &mb_cache_lru_list) {
|
||||
struct mb_cache_entry *ce =
|
||||
list_entry(l, struct mb_cache_entry, e_lru_list);
|
||||
if (ce->e_cache == cache) {
|
||||
list_move_tail(&ce->e_lru_list, &free_list);
|
||||
__mb_cache_entry_unhash(ce);
|
||||
}
|
||||
}
|
||||
list_del(&cache->c_cache_list);
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
|
||||
list_for_each_safe(l, ltmp, &free_list) {
|
||||
__mb_cache_entry_forget(list_entry(l, struct mb_cache_entry,
|
||||
e_lru_list), GFP_KERNEL);
|
||||
}
|
||||
|
||||
if (atomic_read(&cache->c_entry_count) > 0) {
|
||||
mb_error("cache %s: %d orphaned entries",
|
||||
cache->c_name,
|
||||
atomic_read(&cache->c_entry_count));
|
||||
}
|
||||
|
||||
kmem_cache_destroy(cache->c_entry_cache);
|
||||
|
||||
for (n=0; n < mb_cache_indexes(cache); n++)
|
||||
kfree(cache->c_indexes_hash[n]);
|
||||
kfree(cache->c_block_hash);
|
||||
kfree(cache);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_alloc()
|
||||
*
|
||||
* Allocates a new cache entry. The new entry will not be valid initially,
|
||||
* and thus cannot be looked up yet. It should be filled with data, and
|
||||
* then inserted into the cache using mb_cache_entry_insert(). Returns NULL
|
||||
* if no more memory was available.
|
||||
*/
|
||||
struct mb_cache_entry *
|
||||
mb_cache_entry_alloc(struct mb_cache *cache)
|
||||
{
|
||||
struct mb_cache_entry *ce;
|
||||
|
||||
atomic_inc(&cache->c_entry_count);
|
||||
ce = kmem_cache_alloc(cache->c_entry_cache, GFP_KERNEL);
|
||||
if (ce) {
|
||||
INIT_LIST_HEAD(&ce->e_lru_list);
|
||||
INIT_LIST_HEAD(&ce->e_block_list);
|
||||
ce->e_cache = cache;
|
||||
ce->e_used = 1 + MB_CACHE_WRITER;
|
||||
ce->e_queued = 0;
|
||||
}
|
||||
return ce;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_insert()
|
||||
*
|
||||
* Inserts an entry that was allocated using mb_cache_entry_alloc() into
|
||||
* the cache. After this, the cache entry can be looked up, but is not yet
|
||||
* in the lru list as the caller still holds a handle to it. Returns 0 on
|
||||
* success, or -EBUSY if a cache entry for that device + inode exists
|
||||
* already (this may happen after a failed lookup, but when another process
|
||||
* has inserted the same cache entry in the meantime).
|
||||
*
|
||||
* @bdev: device the cache entry belongs to
|
||||
* @block: block number
|
||||
* @keys: array of additional keys. There must be indexes_count entries
|
||||
* in the array (as specified when creating the cache).
|
||||
*/
|
||||
int
|
||||
mb_cache_entry_insert(struct mb_cache_entry *ce, struct block_device *bdev,
|
||||
sector_t block, unsigned int keys[])
|
||||
{
|
||||
struct mb_cache *cache = ce->e_cache;
|
||||
unsigned int bucket;
|
||||
struct list_head *l;
|
||||
int error = -EBUSY, n;
|
||||
|
||||
bucket = hash_long((unsigned long)bdev + (block & 0xffffffff),
|
||||
cache->c_bucket_bits);
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
list_for_each_prev(l, &cache->c_block_hash[bucket]) {
|
||||
struct mb_cache_entry *ce =
|
||||
list_entry(l, struct mb_cache_entry, e_block_list);
|
||||
if (ce->e_bdev == bdev && ce->e_block == block)
|
||||
goto out;
|
||||
}
|
||||
__mb_cache_entry_unhash(ce);
|
||||
ce->e_bdev = bdev;
|
||||
ce->e_block = block;
|
||||
list_add(&ce->e_block_list, &cache->c_block_hash[bucket]);
|
||||
for (n=0; n<mb_cache_indexes(cache); n++) {
|
||||
ce->e_indexes[n].o_key = keys[n];
|
||||
bucket = hash_long(keys[n], cache->c_bucket_bits);
|
||||
list_add(&ce->e_indexes[n].o_list,
|
||||
&cache->c_indexes_hash[n][bucket]);
|
||||
}
|
||||
error = 0;
|
||||
out:
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
return error;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_release()
|
||||
*
|
||||
* Release a handle to a cache entry. When the last handle to a cache entry
|
||||
* is released it is either freed (if it is invalid) or otherwise inserted
|
||||
* in to the lru list.
|
||||
*/
|
||||
void
|
||||
mb_cache_entry_release(struct mb_cache_entry *ce)
|
||||
{
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
__mb_cache_entry_release_unlock(ce);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_free()
|
||||
*
|
||||
* This is equivalent to the sequence mb_cache_entry_takeout() --
|
||||
* mb_cache_entry_release().
|
||||
*/
|
||||
void
|
||||
mb_cache_entry_free(struct mb_cache_entry *ce)
|
||||
{
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
mb_assert(list_empty(&ce->e_lru_list));
|
||||
__mb_cache_entry_unhash(ce);
|
||||
__mb_cache_entry_release_unlock(ce);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_get()
|
||||
*
|
||||
* Get a cache entry by device / block number. (There can only be one entry
|
||||
* in the cache per device and block.) Returns NULL if no such cache entry
|
||||
* exists. The returned cache entry is locked for exclusive access ("single
|
||||
* writer").
|
||||
*/
|
||||
struct mb_cache_entry *
|
||||
mb_cache_entry_get(struct mb_cache *cache, struct block_device *bdev,
|
||||
sector_t block)
|
||||
{
|
||||
unsigned int bucket;
|
||||
struct list_head *l;
|
||||
struct mb_cache_entry *ce;
|
||||
|
||||
bucket = hash_long((unsigned long)bdev + (block & 0xffffffff),
|
||||
cache->c_bucket_bits);
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
list_for_each(l, &cache->c_block_hash[bucket]) {
|
||||
ce = list_entry(l, struct mb_cache_entry, e_block_list);
|
||||
if (ce->e_bdev == bdev && ce->e_block == block) {
|
||||
DEFINE_WAIT(wait);
|
||||
|
||||
if (!list_empty(&ce->e_lru_list))
|
||||
list_del_init(&ce->e_lru_list);
|
||||
|
||||
while (ce->e_used > 0) {
|
||||
ce->e_queued++;
|
||||
prepare_to_wait(&mb_cache_queue, &wait,
|
||||
TASK_UNINTERRUPTIBLE);
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
schedule();
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
ce->e_queued--;
|
||||
}
|
||||
finish_wait(&mb_cache_queue, &wait);
|
||||
ce->e_used += 1 + MB_CACHE_WRITER;
|
||||
|
||||
if (!__mb_cache_entry_is_hashed(ce)) {
|
||||
__mb_cache_entry_release_unlock(ce);
|
||||
return NULL;
|
||||
}
|
||||
goto cleanup;
|
||||
}
|
||||
}
|
||||
ce = NULL;
|
||||
|
||||
cleanup:
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
return ce;
|
||||
}
|
||||
|
||||
#if !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0)
|
||||
|
||||
static struct mb_cache_entry *
|
||||
__mb_cache_entry_find(struct list_head *l, struct list_head *head,
|
||||
int index, struct block_device *bdev, unsigned int key)
|
||||
{
|
||||
while (l != head) {
|
||||
struct mb_cache_entry *ce =
|
||||
list_entry(l, struct mb_cache_entry,
|
||||
e_indexes[index].o_list);
|
||||
if (ce->e_bdev == bdev && ce->e_indexes[index].o_key == key) {
|
||||
DEFINE_WAIT(wait);
|
||||
|
||||
if (!list_empty(&ce->e_lru_list))
|
||||
list_del_init(&ce->e_lru_list);
|
||||
|
||||
/* Incrementing before holding the lock gives readers
|
||||
priority over writers. */
|
||||
ce->e_used++;
|
||||
while (ce->e_used >= MB_CACHE_WRITER) {
|
||||
ce->e_queued++;
|
||||
prepare_to_wait(&mb_cache_queue, &wait,
|
||||
TASK_UNINTERRUPTIBLE);
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
schedule();
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
ce->e_queued--;
|
||||
}
|
||||
finish_wait(&mb_cache_queue, &wait);
|
||||
|
||||
if (!__mb_cache_entry_is_hashed(ce)) {
|
||||
__mb_cache_entry_release_unlock(ce);
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
return ERR_PTR(-EAGAIN);
|
||||
}
|
||||
return ce;
|
||||
}
|
||||
l = l->next;
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_find_first()
|
||||
*
|
||||
* Find the first cache entry on a given device with a certain key in
|
||||
* an additional index. Additonal matches can be found with
|
||||
* mb_cache_entry_find_next(). Returns NULL if no match was found. The
|
||||
* returned cache entry is locked for shared access ("multiple readers").
|
||||
*
|
||||
* @cache: the cache to search
|
||||
* @index: the number of the additonal index to search (0<=index<indexes_count)
|
||||
* @bdev: the device the cache entry should belong to
|
||||
* @key: the key in the index
|
||||
*/
|
||||
struct mb_cache_entry *
|
||||
mb_cache_entry_find_first(struct mb_cache *cache, int index,
|
||||
struct block_device *bdev, unsigned int key)
|
||||
{
|
||||
unsigned int bucket = hash_long(key, cache->c_bucket_bits);
|
||||
struct list_head *l;
|
||||
struct mb_cache_entry *ce;
|
||||
|
||||
mb_assert(index < mb_cache_indexes(cache));
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
l = cache->c_indexes_hash[index][bucket].next;
|
||||
ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
|
||||
index, bdev, key);
|
||||
spin_unlock(&mb_cache_spinlock);
|
||||
return ce;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* mb_cache_entry_find_next()
|
||||
*
|
||||
* Find the next cache entry on a given device with a certain key in an
|
||||
* additional index. Returns NULL if no match could be found. The previous
|
||||
* entry is atomatically released, so that mb_cache_entry_find_next() can
|
||||
* be called like this:
|
||||
*
|
||||
* entry = mb_cache_entry_find_first();
|
||||
* while (entry) {
|
||||
* ...
|
||||
* entry = mb_cache_entry_find_next(entry, ...);
|
||||
* }
|
||||
*
|
||||
* @prev: The previous match
|
||||
* @index: the number of the additonal index to search (0<=index<indexes_count)
|
||||
* @bdev: the device the cache entry should belong to
|
||||
* @key: the key in the index
|
||||
*/
|
||||
struct mb_cache_entry *
|
||||
mb_cache_entry_find_next(struct mb_cache_entry *prev, int index,
|
||||
struct block_device *bdev, unsigned int key)
|
||||
{
|
||||
struct mb_cache *cache = prev->e_cache;
|
||||
unsigned int bucket = hash_long(key, cache->c_bucket_bits);
|
||||
struct list_head *l;
|
||||
struct mb_cache_entry *ce;
|
||||
|
||||
mb_assert(index < mb_cache_indexes(cache));
|
||||
spin_lock(&mb_cache_spinlock);
|
||||
l = prev->e_indexes[index].o_list.next;
|
||||
ce = __mb_cache_entry_find(l, &cache->c_indexes_hash[index][bucket],
|
||||
index, bdev, key);
|
||||
__mb_cache_entry_release_unlock(prev);
|
||||
return ce;
|
||||
}
|
||||
|
||||
#endif /* !defined(MB_CACHE_INDEXES_COUNT) || (MB_CACHE_INDEXES_COUNT > 0) */
|
||||
|
||||
static int __init init_mbcache(void)
|
||||
{
|
||||
mb_shrinker = set_shrinker(DEFAULT_SEEKS, mb_cache_shrink_fn);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void __exit exit_mbcache(void)
|
||||
{
|
||||
remove_shrinker(mb_shrinker);
|
||||
}
|
||||
|
||||
module_init(init_mbcache)
|
||||
module_exit(exit_mbcache)
|
||||
|
||||
Reference in New Issue
Block a user