xfs: add discontiguous buffer map interface

With the internal interfaces supporting discontiguous buffer maps,
add external lookup, read and get interfaces so they can start to be
used.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>

2 files changed, 58 insertions, 25 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 82bb8123ab2b..39c5d7622dec 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -581,22 +581,21 @@ found:
  * more hits than misses.
  */
 struct xfs_buf *
-xfs_buf_get(
-        xfs_buftarg_t           *target,
-        xfs_daddr_t             blkno,
-        size_t                  numblks,
+xfs_buf_get_map(
+        struct xfs_buftarg      *target,
+        struct xfs_buf_map      *map,
+        int                     nmaps,
         xfs_buf_flags_t         flags)
 {
         struct xfs_buf          *bp;
         struct xfs_buf          *new_bp;
         int                     error = 0;
-        DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
 
-        bp = _xfs_buf_find(target, &map, 1, flags, NULL);
+        bp = _xfs_buf_find(target, map, nmaps, flags, NULL);
         if (likely(bp))
                 goto found;
 
-        new_bp = _xfs_buf_alloc(target, &map, 1, flags);
+        new_bp = _xfs_buf_alloc(target, map, nmaps, flags);
         if (unlikely(!new_bp))
                 return NULL;
 
@@ -606,7 +605,7 @@ xfs_buf_get(
                 return NULL;
         }
 
-        bp = _xfs_buf_find(target, &map, 1, flags, new_bp);
+        bp = _xfs_buf_find(target, map, nmaps, flags, new_bp);
         if (!bp) {
                 xfs_buf_free(new_bp);
                 return NULL;
@@ -649,17 +648,17 @@ _xfs_buf_read(
 }
 
 xfs_buf_t *
-xfs_buf_read(
-        xfs_buftarg_t           *target,
-        xfs_daddr_t             blkno,
-        size_t                  numblks,
+xfs_buf_read_map(
+        struct xfs_buftarg      *target,
+        struct xfs_buf_map      *map,
+        int                     nmaps,
         xfs_buf_flags_t         flags)
 {
-        xfs_buf_t               *bp;
+        struct xfs_buf          *bp;
 
         flags |= XBF_READ;
 
-        bp = xfs_buf_get(target, blkno, numblks, flags);
+        bp = xfs_buf_get_map(target, map, nmaps, flags);
         if (bp) {
                 trace_xfs_buf_read(bp, flags, _RET_IP_);
 
@@ -687,15 +686,15 @@ xfs_buf_read(
  *      safe manner.
  */
 void
-xfs_buf_readahead(
-        xfs_buftarg_t           *target,
-        xfs_daddr_t             blkno,
-        size_t                  numblks)
+xfs_buf_readahead_map(
+        struct xfs_buftarg      *target,
+        struct xfs_buf_map      *map,
+        int                     nmaps)
 {
         if (bdi_read_congested(target->bt_bdi))
                 return;
 
-        xfs_buf_read(target, blkno, numblks,
+        xfs_buf_read_map(target, map, nmaps,
                      XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD);
 }
 
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 67d134994ae4..aa96bd410aed 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -184,12 +184,46 @@ xfs_buf_alloc(
         return _xfs_buf_alloc(target, &map, 1, flags);
 }
 
-struct xfs_buf *xfs_buf_get(struct xfs_buftarg *target, xfs_daddr_t blkno,
-                                size_t numblks, xfs_buf_flags_t flags);
-struct xfs_buf *xfs_buf_read(struct xfs_buftarg *target, xfs_daddr_t blkno,
-                                size_t numblks, xfs_buf_flags_t flags);
-void xfs_buf_readahead(struct xfs_buftarg *target, xfs_daddr_t blkno,
-                                size_t numblks);
+struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
+                               struct xfs_buf_map *map, int nmaps,
+                               xfs_buf_flags_t flags);
+struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
+                               struct xfs_buf_map *map, int nmaps,
+                               xfs_buf_flags_t flags);
+void xfs_buf_readahead_map(struct xfs_buftarg *target,
+                               struct xfs_buf_map *map, int nmaps);
+
+static inline struct xfs_buf *
+xfs_buf_get(
+        struct xfs_buftarg      *target,
+        xfs_daddr_t             blkno,
+        size_t                  numblks,
+        xfs_buf_flags_t         flags)
+{
+        DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
+        return xfs_buf_get_map(target, &map, 1, flags);
+}
+
+static inline struct xfs_buf *
+xfs_buf_read(
+        struct xfs_buftarg      *target,
+        xfs_daddr_t             blkno,
+        size_t                  numblks,
+        xfs_buf_flags_t         flags)
+{
+        DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
+        return xfs_buf_read_map(target, &map, 1, flags);
+}
+
+static inline void
+xfs_buf_readahead(
+        struct xfs_buftarg      *target,
+        xfs_daddr_t             blkno,
+        size_t                  numblks)
+{
+        DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
+        return xfs_buf_readahead_map(target, &map, 1);
+}
 
 struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
 void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);