xfs: use blocks for counting length of buffers

Now that we pass block counts everywhere, and index buffers by block
number, track the length of the buffer in units of blocks rather
than bytes. Convert the code to use block counts, and those that
need byte counts get converted at the time of use.

Also, remove the XFS_BUF_{SET_}SIZE() macros that are just wrappers
around the buffer length. They only serve to make the code shouty
loud and don't actually add any real value.

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

1 files changed, 12 insertions, 10 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 854b27a8e77..382c49a42ac 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -198,11 +198,12 @@ xfs_buf_alloc(
         bp->b_target = target;
 
         /*
-         * Set buffer_length and count_desired to the same value initially.
+         * Set length and count_desired to the same value initially.
          * I/O routines should use count_desired, which will be the same in
          * most cases but may be reset (e.g. XFS recovery).
          */
-        bp->b_buffer_length = bp->b_count_desired = numblks << BBSHIFT;
+        bp->b_length = numblks;
+        bp->b_count_desired = numblks << BBSHIFT;
         bp->b_flags = flags;
 
         /*
@@ -313,14 +314,14 @@ xfs_buf_allocate_memory(
          * the memory from the heap - there's no need for the complexity of
          * page arrays to keep allocation down to order 0.
          */
-        if (bp->b_buffer_length < PAGE_SIZE) {
-                bp->b_addr = kmem_alloc(bp->b_buffer_length, xb_to_km(flags));
+        if (bp->b_length < BTOBB(PAGE_SIZE)) {
+                bp->b_addr = kmem_alloc(BBTOB(bp->b_length), xb_to_km(flags));
                 if (!bp->b_addr) {
                         /* low memory - use alloc_page loop instead */
                         goto use_alloc_page;
                 }
 
-                if (((unsigned long)(bp->b_addr + bp->b_buffer_length - 1) &
+                if (((unsigned long)(bp->b_addr + BBTOB(bp->b_length) - 1) &
                                                                 PAGE_MASK) !=
                     ((unsigned long)bp->b_addr & PAGE_MASK)) {
                         /* b_addr spans two pages - use alloc_page instead */
@@ -337,7 +338,7 @@ xfs_buf_allocate_memory(
         }
 
 use_alloc_page:
-        end = BBTOB(bp->b_bn) + bp->b_buffer_length;
+        end = BBTOB(bp->b_bn + bp->b_length);
         page_count = xfs_buf_btoc(end) - xfs_buf_btoct(BBTOB(bp->b_bn));
         error = _xfs_buf_get_pages(bp, page_count, flags);
         if (unlikely(error))
@@ -477,7 +478,7 @@ _xfs_buf_find(
                          * reallocating a busy extent. Skip this buffer and
                          * continue searching to the right for an exact match.
                          */
-                        if (bp->b_buffer_length != numbytes) {
+                        if (bp->b_length != numblks) {
                                 ASSERT(bp->b_flags & XBF_STALE);
                                 rbp = &(*rbp)->rb_right;
                                 continue;
@@ -574,7 +575,7 @@ xfs_buf_get(
          * that we can do IO on it.
          */
         bp->b_bn = blkno;
-        bp->b_count_desired = bp->b_buffer_length;
+        bp->b_count_desired = BBTOB(bp->b_length);
 
 found:
         if (!(bp->b_flags & XBF_MAPPED)) {
@@ -716,7 +717,8 @@ xfs_buf_set_empty(
         bp->b_pages = NULL;
         bp->b_page_count = 0;
         bp->b_addr = NULL;
-        bp->b_buffer_length = bp->b_count_desired = numblks << BBSHIFT;
+        bp->b_length = numblks;
+        bp->b_count_desired = numblks << BBSHIFT;
         bp->b_bn = XFS_BUF_DADDR_NULL;
         bp->b_flags &= ~XBF_MAPPED;
 }
@@ -769,7 +771,7 @@ xfs_buf_associate_memory(
         }
 
         bp->b_count_desired = len;
-        bp->b_buffer_length = buflen;
+        bp->b_length = BTOBB(buflen);
         bp->b_flags |= XBF_MAPPED;
 
         return 0;