[rfc][patch 3/3] xfs: use new vmap API

[Nick Piggin <npiggin@xxxxxxx>]

Implement XFS's large buffer support with the new vmap APIs. See the vmap
rewrite patch for some numbers.

Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
---

Index: linux-2.6/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_buf.c
+++ linux-2.6/fs/xfs/linux-2.6/xfs_buf.c
@@ -265,7 +265,7 @@ xfs_buf_free(
                uint            i;
 
                if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))
-                       vunmap(bp->b_addr - bp->b_offset);
+                       vm_unmap_ram(bp->b_addr - bp->b_offset, 
bp->b_page_count);
 
                for (i = 0; i < bp->b_page_count; i++) {
                        struct page     *page = bp->b_pages[i];
@@ -387,8 +387,8 @@ _xfs_buf_map_pages(
                bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
                bp->b_flags |= XBF_MAPPED;
        } else if (flags & XBF_MAPPED) {
-               bp->b_addr = vmap(bp->b_pages, bp->b_page_count,
-                                       VM_MAP, PAGE_KERNEL);
+               bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
+                                       -1, PAGE_KERNEL);
                if (unlikely(bp->b_addr == NULL))
                        return -ENOMEM;
                bp->b_addr += bp->b_offset;