It doesn't appear hashing the commands on an it_nexus is a benefit. Both it_nexus_destroy and abort_task_set iterate across all lists in the hash, which is equivalent to iterating through the list. Insertion and removal from the list remains O(1). Signed-off-by: Andy Grover <agrover@xxxxxxxxxx> --- usr/hash.h | 58 ---------------------------------------------------------- usr/target.c | 35 ++++++++++++++--------------------- usr/target.h | 7 +------ 3 files changed, 15 insertions(+), 85 deletions(-) delete mode 100644 usr/hash.h diff --git a/usr/hash.h b/usr/hash.h deleted file mode 100644 index cf42d8a..0000000 --- a/usr/hash.h +++ /dev/null @@ -1,58 +0,0 @@ -#ifndef _LINUX_HASH_H -#define _LINUX_HASH_H -/* Fast hashing routine for a long. - (C) 2002 William Lee Irwin III, IBM */ - -/* - * Knuth recommends primes in approximately golden ratio to the maximum - * integer representable by a machine word for multiplicative hashing. - * Chuck Lever verified the effectiveness of this technique: - * http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf - * - * These primes are chosen to be bit-sparse, that is operations on - * them can use shifts and additions instead of multiplications for - * machines where multiplications are slow. - */ -#if BITS_PER_LONG == 32 -/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */ -#define GOLDEN_RATIO_PRIME 0x9e370001UL -#elif BITS_PER_LONG == 64 -/* 2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */ -#define GOLDEN_RATIO_PRIME 0x9e37fffffffc0001UL -#else -#error Define GOLDEN_RATIO_PRIME for your wordsize. -#endif - -static inline unsigned long hash_long(unsigned long val, unsigned int bits) -{ - unsigned long hash = val; - -#if BITS_PER_LONG == 64 - /* Sigh, gcc can't optimise this alone like it does for 32 bits. */ - unsigned long n = hash; - n <<= 18; - hash -= n; - n <<= 33; - hash -= n; - n <<= 3; - hash += n; - n <<= 3; - hash -= n; - n <<= 4; - hash += n; - n <<= 2; - hash += n; -#else - /* On some cpus multiply is faster, on others gcc will do shifts */ - hash *= GOLDEN_RATIO_PRIME; -#endif - - /* High bits are more random, so use them. */ - return hash >> (BITS_PER_LONG - bits); -} - -static inline unsigned long hash_ptr(void *ptr, unsigned int bits) -{ - return hash_long((unsigned long)ptr, bits); -} -#endif /* _LINUX_HASH_H */ diff --git a/usr/target.c b/usr/target.c index 3651767..5a8dfa6 100644 --- a/usr/target.c +++ b/usr/target.c @@ -263,7 +263,7 @@ void ua_sense_add_it_nexus(uint64_t itn_id, struct scsi_lu *lu, int it_nexus_create(int tid, uint64_t itn_id, int host_no, char *info) { - int i, ret; + int ret; struct target *target; struct it_nexus *itn; struct scsi_lu *lu; @@ -308,8 +308,7 @@ int it_nexus_create(int tid, uint64_t itn_id, int host_no, char *info) &itn->it_nexus_lu_info_list); } - for (i = 0; i < ARRAY_SIZE(itn->cmd_hash_list); i++) - INIT_LIST_HEAD(&itn->cmd_hash_list[i]); + INIT_LIST_HEAD(&itn->cmd_list); list_add_tail(&itn->nexus_siblings, &target->it_nexus_list); @@ -321,7 +320,6 @@ out: int it_nexus_destroy(int tid, uint64_t itn_id) { - int i; struct it_nexus *itn; struct scsi_lu *lu; @@ -331,9 +329,8 @@ int it_nexus_destroy(int tid, uint64_t itn_id) if (!itn) return -ENOENT; - for (i = 0; i < ARRAY_SIZE(itn->cmd_hash_list); i++) - if (!list_empty(&itn->cmd_hash_list[i])) - return -EBUSY; + if (!list_empty(&itn->cmd_list)) + return -EBUSY; list_for_each_entry(lu, &itn->nexus_target->device_list, device_siblings) device_release(tid, itn_id, lu->lun, 0); @@ -357,8 +354,7 @@ static struct scsi_lu *device_lookup(struct target *target, uint64_t lun) static void cmd_hlist_insert(struct it_nexus *itn, struct scsi_cmd *cmd) { - struct list_head *list = &itn->cmd_hash_list[hashfn(cmd->tag)]; - list_add(&cmd->c_hlist, list); + list_add(&cmd->c_hlist, &itn->cmd_list); } static void cmd_hlist_remove(struct scsi_cmd *cmd) @@ -1109,22 +1105,19 @@ static int abort_task_set(struct mgmt_req *mreq, struct target* target, { struct scsi_cmd *cmd, *tmp; struct it_nexus *itn; - int i, err, count = 0; + int err, count = 0; eprintf("found %" PRIx64 " %d\n", tag, all); list_for_each_entry(itn, &target->it_nexus_list, nexus_siblings) { - for (i = 0; i < ARRAY_SIZE(itn->cmd_hash_list); i++) { - struct list_head *list = &itn->cmd_hash_list[i]; - list_for_each_entry_safe(cmd, tmp, list, c_hlist) { - if ((all && itn->itn_id == itn_id) || - (cmd->tag == tag && itn->itn_id == itn_id) || - (lun && !memcmp(cmd->lun, lun, sizeof(cmd->lun)))) { - err = abort_cmd(target, mreq, cmd); - if (err) - mreq->busy++; - count++; - } + list_for_each_entry_safe(cmd, tmp, &itn->cmd_list, c_hlist) { + if ((all && itn->itn_id == itn_id) || + (cmd->tag == tag && itn->itn_id == itn_id) || + (lun && !memcmp(cmd->lun, lun, sizeof(cmd->lun)))) { + err = abort_cmd(target, mreq, cmd); + if (err) + mreq->busy++; + count++; } } } diff --git a/usr/target.h b/usr/target.h index f1e51f3..ba03f3c 100644 --- a/usr/target.h +++ b/usr/target.h @@ -2,11 +2,6 @@ #define __TARGET_H__ #include <limits.h> -#define BITS_PER_LONG (ULONG_MAX == 0xFFFFFFFFUL ? 32 : 64) -#include "hash.h" - -#define HASH_ORDER 4 -#define hashfn(val) hash_long((unsigned long) (val), HASH_ORDER) struct acl_entry { char *address; @@ -52,7 +47,7 @@ struct it_nexus { uint64_t itn_id; long ctime; - struct list_head cmd_hash_list[1 << HASH_ORDER]; + struct list_head cmd_list; struct target *nexus_target; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
