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[PATCH 02/10] xfs: refactor xfs_buf_item_format_segment

To: xfs@xxxxxxxxxxx
Subject: [PATCH 02/10] xfs: refactor xfs_buf_item_format_segment
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Fri, 29 Nov 2013 00:39:21 -0800
Delivered-to: xfs@xxxxxxxxxxx
References: <20131129083919.207915844@xxxxxxxxxxxxxxxxxxxxxx>
User-agent: quilt/0.60-1
Add two helpers to make the code more readable.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/xfs/xfs_buf_item.c |   72 ++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index a64f67b..a30c1fb 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -182,6 +182,34 @@ xfs_buf_item_size(
        trace_xfs_buf_item_size(bip);
 }
 
+static inline struct xfs_log_iovec *
+xfs_buf_item_copy_iovec(
+       struct xfs_log_iovec    *vecp,
+       struct xfs_buf          *bp,
+       uint                    offset,
+       int                     first_bit,
+       uint                    nbits)
+{
+       offset += first_bit * XFS_BLF_CHUNK;
+
+       vecp->i_type = XLOG_REG_TYPE_BCHUNK;
+       vecp->i_addr = xfs_buf_offset(bp, offset);
+       vecp->i_len = nbits * XFS_BLF_CHUNK;
+       return vecp + 1;
+}
+
+static inline bool
+xfs_buf_item_straddle(
+       struct xfs_buf          *bp,
+       uint                    offset,
+       int                     next_bit,
+       int                     last_bit)
+{
+       return xfs_buf_offset(bp, offset + (next_bit << XFS_BLF_SHIFT)) !=
+               (xfs_buf_offset(bp, offset + (last_bit << XFS_BLF_SHIFT)) +
+                XFS_BLF_CHUNK);
+}
+
 static struct xfs_log_iovec *
 xfs_buf_item_format_segment(
        struct xfs_buf_log_item *bip,
@@ -196,7 +224,6 @@ xfs_buf_item_format_segment(
        int             last_bit;
        int             next_bit;
        uint            nbits;
-       uint            buffer_offset;
 
        /* copy the flags across from the base format item */
        blfp->blf_flags = bip->__bli_format.blf_flags;
@@ -239,7 +266,6 @@ xfs_buf_item_format_segment(
        /*
         * Fill in an iovec for each set of contiguous chunks.
         */
-
        last_bit = first_bit;
        nbits = 1;
        for (;;) {
@@ -252,42 +278,22 @@ xfs_buf_item_format_segment(
                next_bit = xfs_next_bit(blfp->blf_data_map, blfp->blf_map_size,
                                        (uint)last_bit + 1);
                /*
-                * If we run out of bits fill in the last iovec and get
-                * out of the loop.
-                * Else if we start a new set of bits then fill in the
-                * iovec for the series we were looking at and start
-                * counting the bits in the new one.
-                * Else we're still in the same set of bits so just
-                * keep counting and scanning.
+                * If we run out of bits fill in the last iovec and get out of
+                * the loop.  Else if we start a new set of bits then fill in
+                * the iovec for the series we were looking at and start
+                * counting the bits in the new one.  Else we're still in the
+                * same set of bits so just keep counting and scanning.
                 */
                if (next_bit == -1) {
-                       buffer_offset = offset + first_bit * XFS_BLF_CHUNK;
-                       vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
-                       vecp->i_len = nbits * XFS_BLF_CHUNK;
-                       vecp->i_type = XLOG_REG_TYPE_BCHUNK;
+                       xfs_buf_item_copy_iovec(vecp, bp, offset,
+                                               first_bit, nbits);
                        nvecs++;
                        break;
-               } else if (next_bit != last_bit + 1) {
-                       buffer_offset = offset + first_bit * XFS_BLF_CHUNK;
-                       vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
-                       vecp->i_len = nbits * XFS_BLF_CHUNK;
-                       vecp->i_type = XLOG_REG_TYPE_BCHUNK;
-                       nvecs++;
-                       vecp++;
-                       first_bit = next_bit;
-                       last_bit = next_bit;
-                       nbits = 1;
-               } else if (xfs_buf_offset(bp, offset +
-                                             (next_bit << XFS_BLF_SHIFT)) !=
-                          (xfs_buf_offset(bp, offset +
-                                              (last_bit << XFS_BLF_SHIFT)) +
-                           XFS_BLF_CHUNK)) {
-                       buffer_offset = offset + first_bit * XFS_BLF_CHUNK;
-                       vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
-                       vecp->i_len = nbits * XFS_BLF_CHUNK;
-                       vecp->i_type = XLOG_REG_TYPE_BCHUNK;
+               } else if (next_bit != last_bit + 1 ||
+                          xfs_buf_item_straddle(bp, offset, next_bit, 
last_bit)) {
+                       vecp = xfs_buf_item_copy_iovec(vecp, bp, offset,
+                                                      first_bit, nbits);
                        nvecs++;
-                       vecp++;
                        first_bit = next_bit;
                        last_bit = next_bit;
                        nbits = 1;
-- 
1.7.10.4


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