xfs: convert list of extents to free into a regular list

In struct xfs_bmap_free, convert the open-coded free extent list to
a regular list, then use list_sort to sort it prior to processing.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

2 files changed, 19 insertions, 34 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 8847496f7ccb..2f2c85cc8117 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -575,9 +575,7 @@ xfs_bmap_add_free(
 	xfs_fsblock_t		bno,		/* fs block number of extent */
 	xfs_filblks_t		len)		/* length of extent */
 {
-	xfs_bmap_free_item_t	*cur;		/* current (next) element */
-	xfs_bmap_free_item_t	*new;		/* new element */
-	xfs_bmap_free_item_t	*prev;		/* previous element */
+	struct xfs_bmap_free_item	*new;		/* new element */
 #ifdef DEBUG
 	xfs_agnumber_t		agno;
 	xfs_agblock_t		agbno;
@@ -597,17 +595,7 @@ xfs_bmap_add_free(
 	new = kmem_zone_alloc(xfs_bmap_free_item_zone, KM_SLEEP);
 	new->xbfi_startblock = bno;
 	new->xbfi_blockcount = (xfs_extlen_t)len;
-	for (prev = NULL, cur = flist->xbf_first;
-	     cur != NULL;
-	     prev = cur, cur = cur->xbfi_next) {
-		if (cur->xbfi_startblock >= bno)
-			break;
-	}
-	if (prev)
-		prev->xbfi_next = new;
-	else
-		flist->xbf_first = new;
-	new->xbfi_next = cur;
+	list_add(&new->xbfi_list, &flist->xbf_flist);
 	flist->xbf_count++;
 }
 
@@ -617,14 +605,10 @@ xfs_bmap_add_free(
  */
 void
 xfs_bmap_del_free(
-	xfs_bmap_free_t		*flist,	/* free item list header */
-	xfs_bmap_free_item_t	*prev,	/* previous item on list, if any */
-	xfs_bmap_free_item_t	*free)	/* list item to be freed */
+	struct xfs_bmap_free		*flist,	/* free item list header */
+	struct xfs_bmap_free_item	*free)	/* list item to be freed */
 {
-	if (prev)
-		prev->xbfi_next = free->xbfi_next;
-	else
-		flist->xbf_first = free->xbfi_next;
+	list_del(&free->xbfi_list);
 	flist->xbf_count--;
 	kmem_zone_free(xfs_bmap_free_item_zone, free);
 }
@@ -634,17 +618,16 @@ xfs_bmap_del_free(
  */
 void
 xfs_bmap_cancel(
-	xfs_bmap_free_t		*flist)	/* list of bmap_free_items */
+	struct xfs_bmap_free		*flist)	/* list of bmap_free_items */
 {
-	xfs_bmap_free_item_t	*free;	/* free list item */
-	xfs_bmap_free_item_t	*next;
+	struct xfs_bmap_free_item	*free;	/* free list item */
 
 	if (flist->xbf_count == 0)
 		return;
-	ASSERT(flist->xbf_first != NULL);
-	for (free = flist->xbf_first; free; free = next) {
-		next = free->xbfi_next;
-		xfs_bmap_del_free(flist, NULL, free);
+	while (!list_empty(&flist->xbf_flist)) {
+		free = list_first_entry(&flist->xbf_flist,
+				struct xfs_bmap_free_item, xbfi_list);
+		xfs_bmap_del_free(flist, free);
 	}
 	ASSERT(flist->xbf_count == 0);
 }
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index e081c7694fae..f1f3ae6c0a3f 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -62,12 +62,12 @@ struct xfs_bmalloca {
  * List of extents to be free "later".
  * The list is kept sorted on xbf_startblock.
  */
-typedef struct xfs_bmap_free_item
+struct xfs_bmap_free_item
 {
 	xfs_fsblock_t		xbfi_startblock;/* starting fs block number */
 	xfs_extlen_t		xbfi_blockcount;/* number of blocks in extent */
-	struct xfs_bmap_free_item *xbfi_next;	/* link to next entry */
-} xfs_bmap_free_item_t;
+	struct list_head	xbfi_list;
+};
 
 /*
  * Header for free extent list.
@@ -85,7 +85,7 @@ typedef struct xfs_bmap_free_item
  */
 typedef	struct xfs_bmap_free
 {
-	xfs_bmap_free_item_t	*xbf_first;	/* list of to-be-free extents */
+	struct list_head	xbf_flist;	/* list of to-be-free extents */
 	int			xbf_count;	/* count of items on list */
 	int			xbf_low;	/* alloc in low mode */
 } xfs_bmap_free_t;
@@ -141,8 +141,10 @@ static inline int xfs_bmapi_aflag(int w)
 
 static inline void xfs_bmap_init(xfs_bmap_free_t *flp, xfs_fsblock_t *fbp)
 {
-	((flp)->xbf_first = NULL, (flp)->xbf_count = 0, \
-		(flp)->xbf_low = 0, *(fbp) = NULLFSBLOCK);
+	INIT_LIST_HEAD(&flp->xbf_flist);
+	flp->xbf_count = 0;
+	flp->xbf_low = 0;
+	*fbp = NULLFSBLOCK;
 }
 
 /*