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_merge(struct bio_list *bl, struct bio_list *bl2)
  56 {
  57         if (!bl2->head)
  58                 return;
  59
  60         if (bl->tail)
  61                 bl->tail->bi_next = bl2->head;
  62         else
  63                 bl->head = bl2->head;
  64
  65         bl->tail = bl2->tail;
  66 }
  67
  68 static inline void bio_list_merge_head(struct bio_list *bl,
  69                                        struct bio_list *bl2)
  70 {
  71         if (!bl2->head)
  72                 return;
  73
  74         if (bl->head)
  75                 bl2->tail->bi_next = bl->head;
  76         else
  77                 bl->tail = bl2->tail;
  78
  79         bl->head = bl2->head;
  80 }
  81
  82 static inline struct bio *bio_list_pop(struct bio_list *bl)
  83 {
  84         struct bio *bio = bl->head;
  85
  86         if (bio) {
  87                 bl->head = bl->head->bi_next;
  88                 if (!bl->head)
  89                         bl->tail = NULL;
  90
  91                 bio->bi_next = NULL;
  92         }
  93
  94         return bio;
  95 }
  96
  97 static inline struct bio *bio_list_get(struct bio_list *bl)
  98 {
  99         struct bio *bio = bl->head;
 100
 101         bl->head = bl->tail = NULL;
 102
 103         return bio;
 104 }
 105
 106 #endif /* CONFIG_BLOCK */
 107 #endif