drivers/md/dm-bio-list.h

   1 /*
   2  * Copyright (C) 2004 Red Hat UK Ltd.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #ifndef DM_BIO_LIST_H
   8 #define DM_BIO_LIST_H
   9
  10 #include <linux/bio.h>
  11
  12 #ifdef CONFIG_BLOCK
  13
  14 struct bio_list {
  15         struct bio *head;
  16         struct bio *tail;
  17 };
  18
  19 static inline int bio_list_empty(const struct bio_list *bl)
  20 {
  21         return bl->head == NULL;
  22 }
  23
  24 static inline void bio_list_init(struct bio_list *bl)
  25 {
  26         bl->head = bl->tail = NULL;
  27 }
  28
  29 #define bio_list_for_each(bio, bl) \
  30         for (bio = (bl)->head; bio; bio = bio->bi_next)
  31
  32 static inline unsigned bio_list_size(const struct bio_list *bl)
  33 {
  34         unsigned sz = 0;
  35         struct bio *bio;
  36
  37         bio_list_for_each(bio, bl)
  38                 sz++;
  39
  40         return sz;
  41 }
  42
  43 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
  44 {
  45         bio->bi_next = NULL;
  46
  47         if (bl->tail)
  48                 bl->tail->bi_next = bio;
  49         else
  50                 bl->head = bio;
  51
  52         bl->tail = bio;
  53 }
  54
  55 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
  56 {
  57         bio->bi_next = bl->head;
  58
  59         bl->head = bio;
  60
  61         if (!bl->tail)
  62                 bl->tail = bio;
  63 }
  64
  65 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
  66 {
  67         if (!bl2->head)
  68                 return;
  69
  70         if (bl->tail)
  71                 bl->tail->bi_next = bl2->head;
  72         else
  73                 bl->head = bl2->head;
  74
  75         bl->tail = bl2->tail;
  76 }
  77
  78 static inline void bio_list_merge_head(struct bio_list *bl,
  79                                        struct bio_list *bl2)
  80 {
  81         if (!bl2->head)
  82                 return;
  83
  84         if (bl->head)
  85                 bl2->tail->bi_next = bl->head;
  86         else
  87                 bl->tail = bl2->tail;
  88
  89         bl->head = bl2->head;
  90 }
  91
  92 static inline struct bio *bio_list_pop(struct bio_list *bl)
  93 {
  94         struct bio *bio = bl->head;
  95
  96         if (bio) {
  97                 bl->head = bl->head->bi_next;
  98                 if (!bl->head)
  99                         bl->tail = NULL;
 100
 101                 bio->bi_next = NULL;
 102         }
 103
 104         return bio;
 105 }
 106
 107 static inline struct bio *bio_list_get(struct bio_list *bl)
 108 {
 109         struct bio *bio = bl->head;
 110
 111         bl->head = bl->tail = NULL;
 112
 113         return bio;
 114 }
 115
 116 #endif /* CONFIG_BLOCK */
 117 #endif