release/src-rt-6.x/linux/linux-2.6/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 #include <linux/prefetch.h>
  12
  13 struct bio_list {
  14         struct bio *head;
  15         struct bio *tail;
  16 };
  17
  18 static inline int bio_list_empty(const struct bio_list *bl)
  19 {
  20         return bl->head == NULL;
  21 }
  22
  23 #define BIO_LIST_INIT { .head = NULL, .tail = NULL }
  24
  25 #define BIO_LIST(bl) \
  26         struct bio_list bl = BIO_LIST_INIT
  27
  28 static inline void bio_list_init(struct bio_list *bl)
  29 {
  30         bl->head = bl->tail = NULL;
  31 }
  32
  33 #define bio_list_for_each(bio, bl) \
  34         for (bio = (bl)->head; bio && ({ prefetch(bio->bi_next); 1; }); \
  35              bio = bio->bi_next)
  36
  37 static inline unsigned bio_list_size(const struct bio_list *bl)
  38 {
  39         unsigned sz = 0;
  40         struct bio *bio;
  41
  42         bio_list_for_each(bio, bl)
  43                 sz++;
  44
  45         return sz;
  46 }
  47
  48 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
  49 {
  50         bio->bi_next = NULL;
  51
  52         if (bl->tail)
  53                 bl->tail->bi_next = bio;
  54         else
  55                 bl->head = bio;
  56
  57         bl->tail = bio;
  58 }
  59
  60 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
  61 {
  62         if (!bl2->head)
  63                 return;
  64
  65         if (bl->tail)
  66                 bl->tail->bi_next = bl2->head;
  67         else
  68                 bl->head = bl2->head;
  69
  70         bl->tail = bl2->tail;
  71 }
  72
  73 static inline void bio_list_merge_head(struct bio_list *bl,
  74                                        struct bio_list *bl2)
  75 {
  76         if (!bl2->head)
  77                 return;
  78
  79         if (bl->head)
  80                 bl2->tail->bi_next = bl->head;
  81         else
  82                 bl->tail = bl2->tail;
  83
  84         bl->head = bl2->head;
  85 }
  86
  87 static inline struct bio *bio_list_pop(struct bio_list *bl)
  88 {
  89         struct bio *bio = bl->head;
  90
  91         if (bio) {
  92                 bl->head = bl->head->bi_next;
  93                 if (!bl->head)
  94                         bl->tail = NULL;
  95
  96                 bio->bi_next = NULL;
  97         }
  98
  99         return bio;
 100 }
 101
 102 static inline struct bio *bio_list_get(struct bio_list *bl)
 103 {
 104         struct bio *bio = bl->head;
 105
 106         bl->head = bl->tail = NULL;
 107
 108         return bio;
 109 }
 110
 111 #endif