kernel/drivers/scsi/mr_sas/mr_sas_list.c

   1 /*
   2  * mr_sas_list.h: header for mr_sas
   3  *
   4  * Solaris MegaRAID driver for SAS2.0 controllers
   5  * Copyright (c) 2008-2012, LSI Logic Corporation.
   6  * All rights reserved.
   7  */
   8
   9 /* Copyright 2012 Nexenta Systems, Inc. All rights reserved. */
  10
  11 /*
  12  * Extract C functions from LSI-provided mr_sas_list.h such that we can both
  13  * be lint-clean and provide a slightly better source organizational model
  14  * beyond preprocessor abuse.
  15  */
  16
  17 #include "mr_sas_list.h"
  18
  19 /*
  20  * Insert a new entry between two known consecutive entries.
  21  *
  22  * This is only for internal list manipulation where we know
  23  * the prev/next entries already!
  24  */
  25 static inline void
  26 __list_add(struct mlist_head *new, struct mlist_head *prev,
  27     struct mlist_head *next)
  28 {
  29         next->prev = new;
  30         new->next = next;
  31         new->prev = prev;
  32         prev->next = new;
  33 }
  34
  35 /*
  36  * mlist_add - add a new entry
  37  * @new: new entry to be added
  38  * @head: list head to add it after
  39  *
  40  * Insert a new entry after the specified head.
  41  * This is good for implementing stacks.
  42  */
  43 void
  44 mlist_add(struct mlist_head *new, struct mlist_head *head)
  45 {
  46         __list_add(new, head, head->next);
  47 }
  48
  49 /*
  50  * mlist_add_tail - add a new entry
  51  * @new: new entry to be added
  52  * @head: list head to add it before
  53  *
  54  * Insert a new entry before the specified head.
  55  * This is useful for implementing queues.
  56  */
  57 void
  58 mlist_add_tail(struct mlist_head *new, struct mlist_head *head)
  59 {
  60         __list_add(new, head->prev, head);
  61 }
  62
  63 /*
  64  * Delete a list entry by making the prev/next entries
  65  * point to each other.
  66  *
  67  * This is only for internal list manipulation where we know
  68  * the prev/next entries already!
  69  */
  70 static inline void
  71 __list_del(struct mlist_head *prev, struct mlist_head *next)
  72 {
  73         next->prev = prev;
  74         prev->next = next;
  75 }
  76
  77 /*
  78  * mlist_del_init - deletes entry from list and reinitialize it.
  79  * @entry: the element to delete from the list.
  80  */
  81 void
  82 mlist_del_init(struct mlist_head *entry)
  83 {
  84         __list_del(entry->prev, entry->next);
  85         INIT_LIST_HEAD(entry);
  86 }
  87
  88 /*
  89  * mlist_empty - tests whether a list is empty
  90  * @head: the list to test.
  91  */
  92 int
  93 mlist_empty(struct mlist_head *head)
  94 {
  95         return (head->next == head);
  96 }
  97
  98 /*
  99  * mlist_splice - join two lists
 100  * @list: the new list to add.
 101  * @head: the place to add it in the first list.
 102  */
 103 void
 104 mlist_splice(struct mlist_head *list, struct mlist_head *head)
 105 {
 106         struct mlist_head *first = list->next;
 107
 108         if (first != list) {
 109                 struct mlist_head *last = list->prev;
 110                 struct mlist_head *at = head->next;
 111
 112                 first->prev = head;
 113                 head->next = first;
 114
 115                 last->next = at;
 116                 at->prev = last;
 117         }
 118 }