drivers/s390/cio/idset.c

   1 /*
   2  *  drivers/s390/cio/idset.c
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/bitops.h>
  10 #include "idset.h"
  11 #include "css.h"
  12
  13 struct idset {
  14         int num_ssid;
  15         int num_id;
  16         unsigned long bitmap[0];
  17 };
  18
  19 static inline unsigned long bitmap_size(int num_ssid, int num_id)
  20 {
  21         return __BITOPS_WORDS(num_ssid * num_id) * sizeof(unsigned long);
  22 }
  23
  24 static struct idset *idset_new(int num_ssid, int num_id)
  25 {
  26         struct idset *set;
  27
  28         set = kzalloc(sizeof(struct idset) + bitmap_size(num_ssid, num_id),
  29                       GFP_KERNEL);
  30         if (set) {
  31                 set->num_ssid = num_ssid;
  32                 set->num_id = num_id;
  33         }
  34         return set;
  35 }
  36
  37 void idset_free(struct idset *set)
  38 {
  39         kfree(set);
  40 }
  41
  42 void idset_clear(struct idset *set)
  43 {
  44         memset(set->bitmap, 0, bitmap_size(set->num_ssid, set->num_id));
  45 }
  46
  47 void idset_fill(struct idset *set)
  48 {
  49         memset(set->bitmap, 0xff, bitmap_size(set->num_ssid, set->num_id));
  50 }
  51
  52 static inline void idset_add(struct idset *set, int ssid, int id)
  53 {
  54         set_bit(ssid * set->num_id + id, set->bitmap);
  55 }
  56
  57 static inline void idset_del(struct idset *set, int ssid, int id)
  58 {
  59         clear_bit(ssid * set->num_id + id, set->bitmap);
  60 }
  61
  62 static inline int idset_contains(struct idset *set, int ssid, int id)
  63 {
  64         return test_bit(ssid * set->num_id + id, set->bitmap);
  65 }
  66
  67 static inline int idset_get_first(struct idset *set, int *ssid, int *id)
  68 {
  69         int bitnum;
  70
  71         bitnum = find_first_bit(set->bitmap, set->num_ssid * set->num_id);
  72         if (bitnum >= set->num_ssid * set->num_id)
  73                 return 0;
  74         *ssid = bitnum / set->num_id;
  75         *id = bitnum % set->num_id;
  76         return 1;
  77 }
  78
  79 struct idset *idset_sch_new(void)
  80 {
  81         return idset_new(__MAX_SSID + 1, __MAX_SUBCHANNEL + 1);
  82 }
  83
  84 void idset_sch_add(struct idset *set, struct subchannel_id schid)
  85 {
  86         idset_add(set, schid.ssid, schid.sch_no);
  87 }
  88
  89 void idset_sch_del(struct idset *set, struct subchannel_id schid)
  90 {
  91         idset_del(set, schid.ssid, schid.sch_no);
  92 }
  93
  94 int idset_sch_contains(struct idset *set, struct subchannel_id schid)
  95 {
  96         return idset_contains(set, schid.ssid, schid.sch_no);
  97 }
  98
  99 int idset_sch_get_first(struct idset *set, struct subchannel_id *schid)
 100 {
 101         int ssid = 0;
 102         int id = 0;
 103         int rc;
 104
 105         rc = idset_get_first(set, &ssid, &id);
 106         if (rc) {
 107                 init_subchannel_id(schid);
 108                 schid->ssid = ssid;
 109                 schid->sch_no = id;
 110         }
 111         return rc;
 112 }