From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH v7 01/16] hashtable: introduce a small and naive hashtable Date: Sun, 28 Oct 2012 15:02:13 -0400 Message-ID: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: snitzer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org, fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org, paul.gortmaker-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, rds-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org, eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, venkat.x.venkatsubra-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, ccaulfie-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org, ericvh-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org, rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org, lw-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org, Sasha Levin , axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, edumazet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ejt-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, teigland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org To: torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dev-bounces-yBygre7rU0TnMu66kgdUjQ@public.gmane.org Errors-To: dev-bounces-yBygre7rU0TnMu66kgdUjQ@public.gmane.org List-Id: netdev.vger.kernel.org This hashtable implementation is using hlist buckets to provide a simple hashtable to prevent it from getting reimplemented all over the kernel. Signed-off-by: Sasha Levin --- Sorry for the long delay, I was busy with a bunch of personal things. Changes since v6: - Use macros that point to internal static inline functions instead of implementing everything as a macro. - Rebase on latest -next. - Resending the enter patch series on request. - Break early from hash_empty() if found to be non-empty. - DECLARE_HASHTABLE/DEFINE_HASHTABLE. include/linux/hashtable.h | 193 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 include/linux/hashtable.h diff --git a/include/linux/hashtable.h b/include/linux/hashtable.h new file mode 100644 index 0000000..1fb8c97 --- /dev/null +++ b/include/linux/hashtable.h @@ -0,0 +1,193 @@ +/* + * Statically sized hash table implementation + * (C) 2012 Sasha Levin + */ + +#ifndef _LINUX_HASHTABLE_H +#define _LINUX_HASHTABLE_H + +#include +#include +#include +#include +#include + +#define DEFINE_HASHTABLE(name, bits) \ + struct hlist_head name[1 << bits] = \ + { [0 ... ((1 << bits) - 1)] = HLIST_HEAD_INIT } + +#define DECLARE_HASHTABLE(name, bits) \ + struct hlist_head name[1 << (bits)] + +#define HASH_SIZE(name) (ARRAY_SIZE(name)) +#define HASH_BITS(name) ilog2(HASH_SIZE(name)) + +/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */ +#define hash_min(val, bits) \ +({ \ + sizeof(val) <= 4 ? \ + hash_32(val, bits) : \ + hash_long(val, bits); \ +}) + +static inline void __hash_init(struct hlist_head *ht, int sz) +{ + int i; + + for (i = 0; i < sz; i++) + INIT_HLIST_HEAD(&ht[sz]); +} + +/** + * hash_init - initialize a hash table + * @hashtable: hashtable to be initialized + * + * Calculates the size of the hashtable from the given parameter, otherwise + * same as hash_init_size. + * + * This has to be a macro since HASH_BITS() will not work on pointers since + * it calculates the size during preprocessing. + */ +#define hash_init(hashtable) __hash_init(hashtable, HASH_SIZE(hashtable)) + +/** + * hash_add - add an object to a hashtable + * @hashtable: hashtable to add to + * @node: the &struct hlist_node of the object to be added + * @key: the key of the object to be added + */ +#define hash_add(hashtable, node, key) \ + hlist_add_head(node, &hashtable[hash_min(key, HASH_BITS(hashtable))]); + +/** + * hash_add_rcu - add an object to a rcu enabled hashtable + * @hashtable: hashtable to add to + * @node: the &struct hlist_node of the object to be added + * @key: the key of the object to be added + */ +#define hash_add_rcu(hashtable, node, key) \ + hlist_add_head_rcu(node, &hashtable[hash_min(key, HASH_BITS(hashtable))]); + +/** + * hash_hashed - check whether an object is in any hashtable + * @node: the &struct hlist_node of the object to be checked + */ +#define hash_hashed(node) (!hlist_unhashed(node)) + +static inline bool __hash_empty(struct hlist_head *ht, int sz) +{ + int i; + + for (i = 0; i < sz; i++) + if (!hlist_empty(&ht[i])) + return false; + + return true; +} + +/** + * hash_empty - check whether a hashtable is empty + * @hashtable: hashtable to check + * + * This has to be a macro since HASH_BITS() will not work on pointers since + * it calculates the size during preprocessing. + */ +#define hash_empty(hashtable) __hash_empty(hashtable, HASH_SIZE(hashtable)) + +/** + * hash_del - remove an object from a hashtable + * @node: &struct hlist_node of the object to remove + */ +static inline void hash_del(struct hlist_node *node) +{ + hlist_del_init(node); +} + +/** + * hash_del_rcu - remove an object from a rcu enabled hashtable + * @node: &struct hlist_node of the object to remove + */ +static inline void hash_del_rcu(struct hlist_node *node) +{ + hlist_del_init_rcu(node); +} + +/** + * hash_for_each - iterate over a hashtable + * @name: hashtable to iterate + * @bkt: integer to use as bucket loop cursor + * @node: the &struct list_head to use as a loop cursor for each entry + * @obj: the type * to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + */ +#define hash_for_each(name, bkt, node, obj, member) \ + for (bkt = 0, node = NULL; node == NULL && bkt < HASH_SIZE(name); bkt++)\ + hlist_for_each_entry(obj, node, &name[bkt], member) + +/** + * hash_for_each_rcu - iterate over a rcu enabled hashtable + * @name: hashtable to iterate + * @bkt: integer to use as bucket loop cursor + * @node: the &struct list_head to use as a loop cursor for each entry + * @obj: the type * to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + */ +#define hash_for_each_rcu(name, bkt, node, obj, member) \ + for (bkt = 0, node = NULL; node == NULL && bkt < HASH_SIZE(name); bkt++)\ + hlist_for_each_entry_rcu(obj, node, &name[bkt], member) + +/** + * hash_for_each_safe - iterate over a hashtable safe against removal of + * hash entry + * @name: hashtable to iterate + * @bkt: integer to use as bucket loop cursor + * @node: the &struct list_head to use as a loop cursor for each entry + * @tmp: a &struct used for temporary storage + * @obj: the type * to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + */ +#define hash_for_each_safe(name, bkt, node, tmp, obj, member) \ + for (bkt = 0, node = NULL; node == NULL && bkt < HASH_SIZE(name); bkt++)\ + hlist_for_each_entry_safe(obj, node, tmp, &name[bkt], member) + +/** + * hash_for_each_possible - iterate over all possible objects hashing to the + * same bucket + * @name: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @node: the &struct list_head to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + * @key: the key of the objects to iterate over + */ +#define hash_for_each_possible(name, obj, node, member, key) \ + hlist_for_each_entry(obj, node, &name[hash_min(key, HASH_BITS(name))], member) + +/** + * hash_for_each_possible_rcu - iterate over all possible objects hashing to the + * same bucket in an rcu enabled hashtable + * in a rcu enabled hashtable + * @name: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @node: the &struct list_head to use as a loop cursor for each entry + * @member: the name of the hlist_node within the struct + * @key: the key of the objects to iterate over + */ +#define hash_for_each_possible_rcu(name, obj, node, member, key) \ + hlist_for_each_entry_rcu(obj, node, &name[hash_min(key, HASH_BITS(name))], member) + +/** + * hash_for_each_possible_safe - iterate over all possible objects hashing to the + * same bucket safe against removals + * @name: hashtable to iterate + * @obj: the type * to use as a loop cursor for each entry + * @node: the &struct list_head to use as a loop cursor for each entry + * @tmp: a &struct used for temporary storage + * @member: the name of the hlist_node within the struct + * @key: the key of the objects to iterate over + */ +#define hash_for_each_possible_safe(name, obj, node, tmp, member, key) \ + hlist_for_each_entry_safe(obj, node, tmp, \ + &name[hash_min(key, HASH_BITS(name))], member) + + +#endif -- 1.7.12.4