From 61b8cef1d42567d3029e0c7180cbd0f16cc4be2d Mon Sep 17 00:00:00 2001 From: "Emilio G. Cota" Date: Tue, 11 Jul 2017 18:47:38 -0400 Subject: qht: require a default comparison function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit qht_lookup now uses the default cmp function. qht_lookup_custom is defined to retain the old behaviour, that is a cmp function is explicitly provided. qht_insert will gain use of the default cmp in the next patch. Note that we move qht_lookup_custom's @func to be the last argument, which makes the new qht_lookup as simple as possible. Instead of this (i.e. keeping @func 2nd): 0000000000010750 : 10750: 89 d1 mov %edx,%ecx 10752: 48 89 f2 mov %rsi,%rdx 10755: 48 8b 77 08 mov 0x8(%rdi),%rsi 10759: e9 22 ff ff ff jmpq 10680 1075e: 66 90 xchg %ax,%ax We get: 0000000000010740 : 10740: 48 8b 4f 08 mov 0x8(%rdi),%rcx 10744: e9 37 ff ff ff jmpq 10680 10749: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) Reviewed-by: Richard Henderson Reviewed-by: Alex Bennée Signed-off-by: Emilio G. Cota Signed-off-by: Richard Henderson --- include/qemu/qht.h | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/qemu/qht.h b/include/qemu/qht.h index 531aa95..5f03a0f 100644 --- a/include/qemu/qht.h +++ b/include/qemu/qht.h @@ -11,8 +11,11 @@ #include "qemu/thread.h" #include "qemu/qdist.h" +typedef bool (*qht_cmp_func_t)(const void *a, const void *b); + struct qht { struct qht_map *map; + qht_cmp_func_t cmp; QemuMutex lock; /* serializes setters of ht->map */ unsigned int mode; }; @@ -47,10 +50,12 @@ typedef void (*qht_iter_func_t)(struct qht *ht, void *p, uint32_t h, void *up); /** * qht_init - Initialize a QHT * @ht: QHT to be initialized + * @cmp: default comparison function. Cannot be NULL. * @n_elems: number of entries the hash table should be optimized for. * @mode: bitmask with OR'ed QHT_MODE_* */ -void qht_init(struct qht *ht, size_t n_elems, unsigned int mode); +void qht_init(struct qht *ht, qht_cmp_func_t cmp, size_t n_elems, + unsigned int mode); /** * qht_destroy - destroy a previously initialized QHT @@ -78,11 +83,11 @@ void qht_destroy(struct qht *ht); bool qht_insert(struct qht *ht, void *p, uint32_t hash); /** - * qht_lookup - Look up a pointer in a QHT + * qht_lookup_custom - Look up a pointer using a custom comparison function. * @ht: QHT to be looked up - * @func: function to compare existing pointers against @userp * @userp: pointer to pass to @func * @hash: hash of the pointer to be looked up + * @func: function to compare existing pointers against @userp * * Needs to be called under an RCU read-critical section. * @@ -94,8 +99,18 @@ bool qht_insert(struct qht *ht, void *p, uint32_t hash); * Returns the corresponding pointer when a match is found. * Returns NULL otherwise. */ -void *qht_lookup(struct qht *ht, qht_lookup_func_t func, const void *userp, - uint32_t hash); +void *qht_lookup_custom(struct qht *ht, const void *userp, uint32_t hash, + qht_lookup_func_t func); + +/** + * qht_lookup - Look up a pointer in a QHT + * @ht: QHT to be looked up + * @userp: pointer to pass to the comparison function + * @hash: hash of the pointer to be looked up + * + * Calls qht_lookup_custom() using @ht's default comparison function. + */ +void *qht_lookup(struct qht *ht, const void *userp, uint32_t hash); /** * qht_remove - remove a pointer from the hash table -- cgit v1.1