2 files changed, 21 insertions, 23 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index ab3c4491777b..942cf5051ab4 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -306,7 +306,7 @@ xfs_buf_allocate_memory(
         size_t                  nbytes, offset;
         gfp_t                   gfp_mask = xb_to_gfp(flags);
         unsigned short          page_count, i;
-        xfs_off_t               end;
+        xfs_off_t               start, end;
         int                     error;
 
         /*
@@ -314,15 +314,15 @@ 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_length < BTOBB(PAGE_SIZE)) {
-                bp->b_addr = kmem_alloc(BBTOB(bp->b_length), xb_to_km(flags));
+        size = BBTOB(bp->b_length);
+        if (size < PAGE_SIZE) {
+                bp->b_addr = kmem_alloc(size, 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 + BBTOB(bp->b_length) - 1) &
-                                                                PAGE_MASK) !=
+                if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) !=
                     ((unsigned long)bp->b_addr & PAGE_MASK)) {
                         /* b_addr spans two pages - use alloc_page instead */
                         kmem_free(bp->b_addr);
@@ -338,14 +338,14 @@ xfs_buf_allocate_memory(
         }
 
 use_alloc_page:
-        end = BBTOB(bp->b_bn + bp->b_length);
-        page_count = xfs_buf_btoc(end) - xfs_buf_btoct(BBTOB(bp->b_bn));
+        start = BBTOB(bp->b_bn) >> PAGE_SHIFT;
+        end = (BBTOB(bp->b_bn + bp->b_length) + PAGE_SIZE - 1) >> PAGE_SHIFT;
+        page_count = end - start;
         error = _xfs_buf_get_pages(bp, page_count, flags);
         if (unlikely(error))
                 return error;
 
         offset = bp->b_offset;
-        size = BBTOB(bp->b_length);
         bp->b_flags |= _XBF_PAGES;
 
         for (i = 0; i < bp->b_page_count; i++) {
@@ -1320,27 +1320,30 @@ xfs_buf_iomove(
         void                    *data,  /* data address                 */
         xfs_buf_rw_t            mode)   /* read/write/zero flag         */
 {
-        size_t                  bend, cpoff, csize;
-        struct page             *page;
+        size_t                  bend;
 
         bend = boff + bsize;
         while (boff < bend) {
-                page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)];
-                cpoff = xfs_buf_poff(boff + bp->b_offset);
-                csize = min_t(size_t,
-                              PAGE_SIZE - cpoff, BBTOB(bp->b_io_length) - boff);
+                struct page     *page;
+                int             page_index, page_offset, csize;
+
+                page_index = (boff + bp->b_offset) >> PAGE_SHIFT;
+                page_offset = (boff + bp->b_offset) & ~PAGE_MASK;
+                page = bp->b_pages[page_index];
+                csize = min_t(size_t, PAGE_SIZE - page_offset,
+                                      BBTOB(bp->b_io_length) - boff);
 
-                ASSERT(((csize + cpoff) <= PAGE_SIZE));
+                ASSERT((csize + page_offset) <= PAGE_SIZE);
 
                 switch (mode) {
                 case XBRW_ZERO:
-                        memset(page_address(page) + cpoff, 0, csize);
+                        memset(page_address(page) + page_offset, 0, csize);
                         break;
                 case XBRW_READ:
-                        memcpy(data, page_address(page) + cpoff, csize);
+                        memcpy(data, page_address(page) + page_offset, csize);
                         break;
                 case XBRW_WRITE:
-                        memcpy(page_address(page) + cpoff, data, csize);
+                        memcpy(page_address(page) + page_offset, data, csize);
                 }
 
                 boff += csize;
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 9787645fa54c..5b048f7d13ea 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -32,11 +32,6 @@
 
 #define XFS_BUF_DADDR_NULL      ((xfs_daddr_t) (-1LL))
 
-#define xfs_buf_ctob(pp)        ((pp) * PAGE_CACHE_SIZE)
-#define xfs_buf_btoc(dd)        (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
-#define xfs_buf_btoct(dd)       ((dd) >> PAGE_CACHE_SHIFT)
-#define xfs_buf_poff(aa)        ((aa) & ~PAGE_CACHE_MASK)
-
 typedef enum {
         XBRW_READ = 1,                  /* transfer into target memory */
         XBRW_WRITE = 2,                 /* transfer from target memory */