83b3370c79
Use a bitmap for indicating which subchannels require evaluation instead of allocating memory for each evaluation request. This approach reduces memory consumption during recovery in case of massive evaluation request occurrence and removes the need for memory allocation failure handling. Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
113 lines
2.3 KiB
C
113 lines
2.3 KiB
C
/*
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* drivers/s390/cio/idset.c
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*
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* Copyright IBM Corp. 2007
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* Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
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*/
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#include <linux/slab.h>
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#include <asm/bitops.h>
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#include "idset.h"
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#include "css.h"
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struct idset {
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int num_ssid;
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int num_id;
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unsigned long bitmap[0];
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};
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static inline unsigned long bitmap_size(int num_ssid, int num_id)
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{
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return __BITOPS_WORDS(num_ssid * num_id) * sizeof(unsigned long);
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}
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static struct idset *idset_new(int num_ssid, int num_id)
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{
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struct idset *set;
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set = kzalloc(sizeof(struct idset) + bitmap_size(num_ssid, num_id),
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GFP_KERNEL);
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if (set) {
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set->num_ssid = num_ssid;
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set->num_id = num_id;
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}
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return set;
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}
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void idset_free(struct idset *set)
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{
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kfree(set);
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}
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void idset_clear(struct idset *set)
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{
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memset(set->bitmap, 0, bitmap_size(set->num_ssid, set->num_id));
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}
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void idset_fill(struct idset *set)
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{
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memset(set->bitmap, 0xff, bitmap_size(set->num_ssid, set->num_id));
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}
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static inline void idset_add(struct idset *set, int ssid, int id)
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{
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set_bit(ssid * set->num_id + id, set->bitmap);
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}
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static inline void idset_del(struct idset *set, int ssid, int id)
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{
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clear_bit(ssid * set->num_id + id, set->bitmap);
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}
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static inline int idset_contains(struct idset *set, int ssid, int id)
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{
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return test_bit(ssid * set->num_id + id, set->bitmap);
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}
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static inline int idset_get_first(struct idset *set, int *ssid, int *id)
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{
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int bitnum;
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bitnum = find_first_bit(set->bitmap, set->num_ssid * set->num_id);
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if (bitnum >= set->num_ssid * set->num_id)
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return 0;
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*ssid = bitnum / set->num_id;
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*id = bitnum % set->num_id;
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return 1;
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}
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struct idset *idset_sch_new(void)
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{
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return idset_new(__MAX_SSID + 1, __MAX_SUBCHANNEL + 1);
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}
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void idset_sch_add(struct idset *set, struct subchannel_id schid)
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{
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idset_add(set, schid.ssid, schid.sch_no);
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}
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void idset_sch_del(struct idset *set, struct subchannel_id schid)
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{
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idset_del(set, schid.ssid, schid.sch_no);
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}
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int idset_sch_contains(struct idset *set, struct subchannel_id schid)
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{
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return idset_contains(set, schid.ssid, schid.sch_no);
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}
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int idset_sch_get_first(struct idset *set, struct subchannel_id *schid)
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{
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int ssid = 0;
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int id = 0;
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int rc;
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rc = idset_get_first(set, &ssid, &id);
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if (rc) {
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init_subchannel_id(schid);
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schid->ssid = ssid;
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schid->sch_no = id;
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}
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return rc;
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}
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