block: move bio list helpers into bio.h

It's used by DM and MD and generally useful, so move the bio list
helpers into bio.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

10 files changed, 109 insertions, 126 deletions

diff --git a/drivers/md/dm-bio-list.h b/drivers/md/dm-bio-list.h
deleted file mode 100644
index 345098b4ca77..000000000000
--- a/drivers/md/dm-bio-list.h
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright (C) 2004 Red Hat UK Ltd.
- *
- * This file is released under the GPL.
- */
-
-#ifndef DM_BIO_LIST_H
-#define DM_BIO_LIST_H
-
-#include <linux/bio.h>
-
-#ifdef CONFIG_BLOCK
-
-struct bio_list {
-	struct bio *head;
-	struct bio *tail;
-};
-
-static inline int bio_list_empty(const struct bio_list *bl)
-{
-	return bl->head == NULL;
-}
-
-static inline void bio_list_init(struct bio_list *bl)
-{
-	bl->head = bl->tail = NULL;
-}
-
-#define bio_list_for_each(bio, bl) \
-	for (bio = (bl)->head; bio; bio = bio->bi_next)
-
-static inline unsigned bio_list_size(const struct bio_list *bl)
-{
-	unsigned sz = 0;
-	struct bio *bio;
-
-	bio_list_for_each(bio, bl)
-		sz++;
-
-	return sz;
-}
-
-static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
-{
-	bio->bi_next = NULL;
-
-	if (bl->tail)
-		bl->tail->bi_next = bio;
-	else
-		bl->head = bio;
-
-	bl->tail = bio;
-}
-
-static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
-{
-	bio->bi_next = bl->head;
-
-	bl->head = bio;
-
-	if (!bl->tail)
-		bl->tail = bio;
-}
-
-static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
-{
-	if (!bl2->head)
-		return;
-
-	if (bl->tail)
-		bl->tail->bi_next = bl2->head;
-	else
-		bl->head = bl2->head;
-
-	bl->tail = bl2->tail;
-}
-
-static inline void bio_list_merge_head(struct bio_list *bl,
-				       struct bio_list *bl2)
-{
-	if (!bl2->head)
-		return;
-
-	if (bl->head)
-		bl2->tail->bi_next = bl->head;
-	else
-		bl->tail = bl2->tail;
-
-	bl->head = bl2->head;
-}
-
-static inline struct bio *bio_list_pop(struct bio_list *bl)
-{
-	struct bio *bio = bl->head;
-
-	if (bio) {
-		bl->head = bl->head->bi_next;
-		if (!bl->head)
-			bl->tail = NULL;
-
-		bio->bi_next = NULL;
-	}
-
-	return bio;
-}
-
-static inline struct bio *bio_list_get(struct bio_list *bl)
-{
-	struct bio *bio = bl->head;
-
-	bl->head = bl->tail = NULL;
-
-	return bio;
-}
-
-#endif /* CONFIG_BLOCK */
-#endif
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 59ee1b015d2d..559dbb52bc85 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -15,8 +15,6 @@
 
 #include <linux/device-mapper.h>
 
-#include "dm-bio-list.h"
-
 #define DM_MSG_PREFIX "delay"
 
 struct delay_c {
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 095f77bf9681..6a386ab4f7eb 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -8,7 +8,6 @@
 #include <linux/device-mapper.h>
 
 #include "dm-path-selector.h"
-#include "dm-bio-list.h"
 #include "dm-bio-record.h"
 #include "dm-uevent.h"
 
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 536ef0bef154..076fbb4e967a 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -5,7 +5,6 @@
  * This file is released under the GPL.
  */
 
-#include "dm-bio-list.h"
 #include "dm-bio-record.h"
 
 #include <linux/init.h>
diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c
index 59f8d9df9e1a..7b899be0b087 100644
--- a/drivers/md/dm-region-hash.c
+++ b/drivers/md/dm-region-hash.c
@@ -14,7 +14,6 @@
 #include <linux/vmalloc.h>
 
 #include "dm.h"
-#include "dm-bio-list.h"
 
 #define	DM_MSG_PREFIX	"region hash"
 
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 981a0413068f..d73f17fc7778 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -22,7 +22,6 @@
 #include <linux/workqueue.h>
 
 #include "dm-exception-store.h"
-#include "dm-bio-list.h"
 
 #define DM_MSG_PREFIX "snapshots"
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8a994be035ba..424f7b048c30 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -6,7 +6,6 @@
  */
 
 #include "dm.h"
-#include "dm-bio-list.h"
 #include "dm-uevent.h"
 
 #include <linux/init.h>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 274b491a11c1..36df9109cde1 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -35,7 +35,6 @@
 #include <linux/blkdev.h>
 #include <linux/seq_file.h>
 #include "md.h"
-#include "dm-bio-list.h"
 #include "raid1.h"
 #include "bitmap.h"
 
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e293d92641ac..81a54f17417e 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -22,7 +22,6 @@
 #include <linux/blkdev.h>
 #include <linux/seq_file.h>
 #include "md.h"
-#include "dm-bio-list.h"
 #include "raid10.h"
 #include "bitmap.h"
 
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b900d2c67d29..b89cf2d82898 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -504,6 +504,115 @@ static inline int bio_has_data(struct bio *bio)
 	return bio && bio->bi_io_vec != NULL;
 }
 
+/*
+ * BIO list managment for use by remapping drivers (e.g. DM or MD).
+ *
+ * A bio_list anchors a singly-linked list of bios chained through the bi_next
+ * member of the bio.  The bio_list also caches the last list member to allow
+ * fast access to the tail.
+ */
+struct bio_list {
+	struct bio *head;
+	struct bio *tail;
+};
+
+static inline int bio_list_empty(const struct bio_list *bl)
+{
+	return bl->head == NULL;
+}
+
+static inline void bio_list_init(struct bio_list *bl)
+{
+	bl->head = bl->tail = NULL;
+}
+
+#define bio_list_for_each(bio, bl) \
+	for (bio = (bl)->head; bio; bio = bio->bi_next)
+
+static inline unsigned bio_list_size(const struct bio_list *bl)
+{
+	unsigned sz = 0;
+	struct bio *bio;
+
+	bio_list_for_each(bio, bl)
+		sz++;
+
+	return sz;
+}
+
+static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
+{
+	bio->bi_next = NULL;
+
+	if (bl->tail)
+		bl->tail->bi_next = bio;
+	else
+		bl->head = bio;
+
+	bl->tail = bio;
+}
+
+static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
+{
+	bio->bi_next = bl->head;
+
+	bl->head = bio;
+
+	if (!bl->tail)
+		bl->tail = bio;
+}
+
+static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
+{
+	if (!bl2->head)
+		return;
+
+	if (bl->tail)
+		bl->tail->bi_next = bl2->head;
+	else
+		bl->head = bl2->head;
+
+	bl->tail = bl2->tail;
+}
+
+static inline void bio_list_merge_head(struct bio_list *bl,
+				       struct bio_list *bl2)
+{
+	if (!bl2->head)
+		return;
+
+	if (bl->head)
+		bl2->tail->bi_next = bl->head;
+	else
+		bl->tail = bl2->tail;
+
+	bl->head = bl2->head;
+}
+
+static inline struct bio *bio_list_pop(struct bio_list *bl)
+{
+	struct bio *bio = bl->head;
+
+	if (bio) {
+		bl->head = bl->head->bi_next;
+		if (!bl->head)
+			bl->tail = NULL;
+
+		bio->bi_next = NULL;
+	}
+
+	return bio;
+}
+
+static inline struct bio *bio_list_get(struct bio_list *bl)
+{
+	struct bio *bio = bl->head;
+
+	bl->head = bl->tail = NULL;
+
+	return bio;
+}
+
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 
 #define bip_vec_idx(bip, idx)	(&(bip->bip_vec[(idx)]))