[XFS] sanitize xlog_in_core_t definition

Move all fields from xlog_iclog_fields_t into xlog_in_core_t instead of having
them in a substructure and the using #defines to make it look like they were
directly in xlog_in_core_t.  Also document that xlog_in_core_2_t is grossly
misnamed, and make all references to it typesafe.

(First sent on Semptember 15th)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>

3 files changed, 19 insertions, 46 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 8a5b05536a28..aadaa1472f69 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1029,12 +1029,6 @@ xlog_iodone(xfs_buf_t *bp)
         ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) == (unsigned long) 2);
         XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
         aborted = 0;
-
-        /*
-         * Some versions of cpp barf on the recursive definition of
-         * ic_log -> hic_fields.ic_log and expand ic_log twice when
-         * it is passed through two macros.  Workaround broken cpp.
-         */
         l = iclog->ic_log;
 
         /*
@@ -1301,7 +1295,7 @@ xlog_alloc_log(xfs_mount_t	*mp,
                 XFS_BUF_SET_BDSTRAT_FUNC(bp, xlog_bdstrat_cb);
                 XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
                 iclog->ic_bp = bp;
-                iclog->hic_data = bp->b_addr;
+                iclog->ic_data = bp->b_addr;
 #ifdef DEBUG
                 log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);
 #endif
@@ -1321,7 +1315,7 @@ xlog_alloc_log(xfs_mount_t	*mp,
                 atomic_set(&iclog->ic_refcnt, 0);
                 spin_lock_init(&iclog->ic_callback_lock);
                 iclog->ic_callback_tail = &(iclog->ic_callback);
-                iclog->ic_datap = (char *)iclog->hic_data + log->l_iclog_hsize;
+                iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
 
                 ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
                 ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
@@ -3463,7 +3457,7 @@ xlog_verify_iclog(xlog_t	 *log,
         ptr = iclog->ic_datap;
         base_ptr = ptr;
         ophead = (xlog_op_header_t *)ptr;
-        xhdr = (xlog_in_core_2_t *)&iclog->ic_header;
+        xhdr = iclog->ic_data;
         for (i = 0; i < len; i++) {
                 ophead = (xlog_op_header_t *)ptr;
 
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index b39a1980e82d..654167be0efb 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -310,6 +310,16 @@ typedef struct xlog_rec_ext_header {
 } xlog_rec_ext_header_t;
 
 #ifdef __KERNEL__
+
+/*
+ * Quite misnamed, because this union lays out the actual on-disk log buffer.
+ */
+typedef union xlog_in_core2 {
+        xlog_rec_header_t       hic_header;
+        xlog_rec_ext_header_t   hic_xheader;
+        char                    hic_sector[XLOG_HEADER_SIZE];
+} xlog_in_core_2_t;
+
 /*
  * - A log record header is 512 bytes.  There is plenty of room to grow the
  *      xlog_rec_header_t into the reserved space.
@@ -339,7 +349,7 @@ typedef struct xlog_rec_ext_header {
  * We'll put all the read-only and l_icloglock fields in the first cacheline,
  * and move everything else out to subsequent cachelines.
  */
-typedef struct xlog_iclog_fields {
+typedef struct xlog_in_core {
         sv_t                    ic_force_wait;
         sv_t                    ic_write_wait;
         struct xlog_in_core     *ic_next;
@@ -362,41 +372,11 @@ typedef struct xlog_iclog_fields {
 
         /* reference counts need their own cacheline */
         atomic_t                ic_refcnt ____cacheline_aligned_in_smp;
-} xlog_iclog_fields_t;
-
-typedef union xlog_in_core2 {
-        xlog_rec_header_t       hic_header;
-        xlog_rec_ext_header_t   hic_xheader;
-        char                    hic_sector[XLOG_HEADER_SIZE];
-} xlog_in_core_2_t;
-
-typedef struct xlog_in_core {
-        xlog_iclog_fields_t     hic_fields;
-        xlog_in_core_2_t        *hic_data;
+        xlog_in_core_2_t        *ic_data;
+#define ic_header       ic_data->hic_header
 } xlog_in_core_t;
 
 /*
- * Defines to save our code from this glop.
- */
-#define ic_force_wait   hic_fields.ic_force_wait
-#define ic_write_wait   hic_fields.ic_write_wait
-#define ic_next         hic_fields.ic_next
-#define ic_prev         hic_fields.ic_prev
-#define ic_bp           hic_fields.ic_bp
-#define ic_log          hic_fields.ic_log
-#define ic_callback     hic_fields.ic_callback
-#define ic_callback_lock hic_fields.ic_callback_lock
-#define ic_callback_tail hic_fields.ic_callback_tail
-#define ic_trace        hic_fields.ic_trace
-#define ic_size         hic_fields.ic_size
-#define ic_offset       hic_fields.ic_offset
-#define ic_refcnt       hic_fields.ic_refcnt
-#define ic_bwritecnt    hic_fields.ic_bwritecnt
-#define ic_state        hic_fields.ic_state
-#define ic_datap        hic_fields.ic_datap
-#define ic_header       hic_data->hic_header
-
-/*
  * The reservation head lsn is not made up of a cycle number and block number.
  * Instead, it uses a cycle number and byte number.  Logs don't expect to
  * overflow 31 bits worth of byte offset, so using a byte number will mean
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index d94987915d5e..9abb96a7674d 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3332,7 +3332,6 @@ xlog_pack_data(
         int                     size = iclog->ic_offset + roundoff;
         __be32                  cycle_lsn;
         xfs_caddr_t             dp;
-        xlog_in_core_2_t        *xhdr;
 
         xlog_pack_data_checksum(log, iclog, size);
 
@@ -3347,7 +3346,8 @@ xlog_pack_data(
         }
 
         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
-                xhdr = (xlog_in_core_2_t *)&iclog->ic_header;
+                xlog_in_core_2_t *xhdr = iclog->ic_data;
+
                 for ( ; i < BTOBB(size); i++) {
                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
@@ -3405,7 +3405,6 @@ xlog_unpack_data(
         xlog_t                  *log)
 {
         int                     i, j, k;
-        xlog_in_core_2_t        *xhdr;
 
         for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
                   i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
@@ -3414,7 +3413,7 @@ xlog_unpack_data(
         }
 
         if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
-                xhdr = (xlog_in_core_2_t *)rhead;
+                xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
                 for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
                         j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
                         k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);