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 struct bio_list {
  13         struct bio *head;
  14         struct bio *tail;
  15 };
  16
  17 static inline int bio_list_empty(const struct bio_list *bl)
  18 {
  19         return bl->head == NULL;
  20 }
  21
  22 #define BIO_LIST_INIT { .head = NULL, .tail = NULL }
  23
  24 #define BIO_LIST(bl) \
  25         struct bio_list bl = BIO_LIST_INIT
  26
  27 static inline void bio_list_init(struct bio_list *bl)
  28 {
  29         bl->head = bl->tail = NULL;
  30 }
  31
  32 #define bio_list_for_each(bio, bl) \
  33         for (bio = (bl)->head; bio; bio = bio->bi_next)
  34
  35 static inline unsigned bio_list_size(const struct bio_list *bl)
  36 {
  37         unsigned sz = 0;
  38         struct bio *bio;
  39
  40         bio_list_for_each(bio, bl)
  41                 sz++;
  42
  43         return sz;
  44 }
  45
  46 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
  47 {
  48         bio->bi_next = NULL;
  49
  50         if (bl->tail)
  51                 bl->tail->bi_next = bio;
  52         else
  53                 bl->head = bio;
  54
  55         bl->tail = bio;
  56 }
  57
  58 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
  59 {
  60         if (!bl2->head)
  61                 return;
  62
  63         if (bl->tail)
  64                 bl->tail->bi_next = bl2->head;
  65         else
  66                 bl->head = bl2->head;
  67
  68         bl->tail = bl2->tail;
  69 }
  70
  71 static inline void bio_list_merge_head(struct bio_list *bl,
  72                                        struct bio_list *bl2)
  73 {
  74         if (!bl2->head)
  75                 return;
  76
  77         if (bl->head)
  78                 bl2->tail->bi_next = bl->head;
  79         else
  80                 bl->tail = bl2->tail;
  81
  82         bl->head = bl2->head;
  83 }
  84
  85 static inline struct bio *bio_list_pop(struct bio_list *bl)
  86 {
  87         struct bio *bio = bl->head;
  88
  89         if (bio) {
  90                 bl->head = bl->head->bi_next;
  91                 if (!bl->head)
  92                         bl->tail = NULL;
  93
  94                 bio->bi_next = NULL;
  95         }
  96
  97         return bio;
  98 }
  99
 100 static inline struct bio *bio_list_get(struct bio_list *bl)
 101 {
 102         struct bio *bio = bl->head;
 103
 104         bl->head = bl->tail = NULL;
 105
 106         return bio;
 107 }
 108
 109 #endif