xfs: use offsetof() in place of offset macros for __xfsstats

Most offset macro mess is used in xfs_stats_format() only, and we can
simply get the right offsets using offsetof(), instead of several macros
to mark the offsets inside __xfsstats structure.

Replace all XFSSTAT_END_* macros by a single helper macro to get the
right offset into __xfsstats, and use this helper in xfs_stats_format()
directly.

The quota stats code, still looks a bit cleaner when using XFSSTAT_*
macros, so, this patch also defines XFSSTAT_START_XQMSTAT and
XFSSTAT_END_XQMSTAT locally to that code. This also should prevent
offset mistakes when updates are done into __xfsstats.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

2 files changed, 31 insertions, 49 deletions

diff --git a/fs/xfs/xfs_stats.c b/fs/xfs/xfs_stats.c
index 740ac9674848..cc509743facd 100644
--- a/fs/xfs/xfs_stats.c
+++ b/fs/xfs/xfs_stats.c
@@ -29,30 +29,30 @@ int xfs_stats_format(struct xfsstats __percpu *stats, char *buf)
                 char    *desc;
                 int     endpoint;
         } xstats[] = {
-                { "extent_alloc",       XFSSTAT_END_EXTENT_ALLOC        },
-                { "abt",                XFSSTAT_END_ALLOC_BTREE         },
-                { "blk_map",            XFSSTAT_END_BLOCK_MAPPING       },
-                { "bmbt",               XFSSTAT_END_BLOCK_MAP_BTREE     },
-                { "dir",                XFSSTAT_END_DIRECTORY_OPS       },
-                { "trans",              XFSSTAT_END_TRANSACTIONS        },
-                { "ig",                 XFSSTAT_END_INODE_OPS           },
-                { "log",                XFSSTAT_END_LOG_OPS             },
-                { "push_ail",           XFSSTAT_END_TAIL_PUSHING        },
-                { "xstrat",             XFSSTAT_END_WRITE_CONVERT       },
-                { "rw",                 XFSSTAT_END_READ_WRITE_OPS      },
-                { "attr",               XFSSTAT_END_ATTRIBUTE_OPS       },
-                { "icluster",           XFSSTAT_END_INODE_CLUSTER       },
-                { "vnodes",             XFSSTAT_END_VNODE_OPS           },
-                { "buf",                XFSSTAT_END_BUF                 },
-                { "abtb2",              XFSSTAT_END_ABTB_V2             },
-                { "abtc2",              XFSSTAT_END_ABTC_V2             },
-                { "bmbt2",              XFSSTAT_END_BMBT_V2             },
-                { "ibt2",               XFSSTAT_END_IBT_V2              },
-                { "fibt2",              XFSSTAT_END_FIBT_V2             },
-                { "rmapbt",             XFSSTAT_END_RMAP_V2             },
-                { "refcntbt",           XFSSTAT_END_REFCOUNT            },
+                { "extent_alloc",       xfsstats_offset(xs_abt_lookup)  },
+                { "abt",                xfsstats_offset(xs_blk_mapr)    },
+                { "blk_map",            xfsstats_offset(xs_bmbt_lookup) },
+                { "bmbt",               xfsstats_offset(xs_dir_lookup)  },
+                { "dir",                xfsstats_offset(xs_trans_sync)  },
+                { "trans",              xfsstats_offset(xs_ig_attempts) },
+                { "ig",                 xfsstats_offset(xs_log_writes)  },
+                { "log",                xfsstats_offset(xs_try_logspace)},
+                { "push_ail",           xfsstats_offset(xs_xstrat_quick)},
+                { "xstrat",             xfsstats_offset(xs_write_calls) },
+                { "rw",                 xfsstats_offset(xs_attr_get)    },
+                { "attr",               xfsstats_offset(xs_iflush_count)},
+                { "icluster",           xfsstats_offset(vn_active)      },
+                { "vnodes",             xfsstats_offset(xb_get)         },
+                { "buf",                xfsstats_offset(xs_abtb_2)      },
+                { "abtb2",              xfsstats_offset(xs_abtc_2)      },
+                { "abtc2",              xfsstats_offset(xs_bmbt_2)      },
+                { "bmbt2",              xfsstats_offset(xs_ibt_2)       },
+                { "ibt2",               xfsstats_offset(xs_fibt_2)      },
+                { "fibt2",              xfsstats_offset(xs_rmap_2)      },
+                { "rmapbt",             xfsstats_offset(xs_refcbt_2)    },
+                { "refcntbt",           xfsstats_offset(xs_qm_dqreclaims)},
                 /* we print both series of quota information together */
-                { "qm",                 XFSSTAT_END_QM                  },
+                { "qm",                 xfsstats_offset(xs_xstrat_bytes)},
         };
 
         /* Loop over all stats groups */
@@ -104,6 +104,10 @@ void xfs_stats_clearall(struct xfsstats __percpu *stats)
 #ifdef CONFIG_PROC_FS
 /* legacy quota interfaces */
 #ifdef CONFIG_XFS_QUOTA
+
+#define XFSSTAT_START_XQMSTAT xfsstats_offset(xs_qm_dqreclaims)
+#define XFSSTAT_END_XQMSTAT xfsstats_offset(xs_qm_dquot)
+
 static int xqm_proc_show(struct seq_file *m, void *v)
 {
         /* maximum; incore; ratio free to inuse; freelist */
@@ -119,7 +123,7 @@ static int xqmstat_proc_show(struct seq_file *m, void *v)
         int j;
 
         seq_printf(m, "qm");
-        for (j = XFSSTAT_END_REFCOUNT; j < XFSSTAT_END_XQMSTAT; j++)
+        for (j = XFSSTAT_START_XQMSTAT; j < XFSSTAT_END_XQMSTAT; j++)
                 seq_printf(m, " %u", counter_val(xfsstats.xs_stats, j));
         seq_putc(m, '\n');
         return 0;
diff --git a/fs/xfs/xfs_stats.h b/fs/xfs/xfs_stats.h
index 130db070e4d8..34d704f703d2 100644
--- a/fs/xfs/xfs_stats.h
+++ b/fs/xfs/xfs_stats.h
@@ -41,17 +41,14 @@ enum {
  * XFS global statistics
  */
 struct __xfsstats {
-# define XFSSTAT_END_EXTENT_ALLOC       4
         uint32_t                xs_allocx;
         uint32_t                xs_allocb;
         uint32_t                xs_freex;
         uint32_t                xs_freeb;
-# define XFSSTAT_END_ALLOC_BTREE        (XFSSTAT_END_EXTENT_ALLOC+4)
         uint32_t                xs_abt_lookup;
         uint32_t                xs_abt_compare;
         uint32_t                xs_abt_insrec;
         uint32_t                xs_abt_delrec;
-# define XFSSTAT_END_BLOCK_MAPPING      (XFSSTAT_END_ALLOC_BTREE+7)
         uint32_t                xs_blk_mapr;
         uint32_t                xs_blk_mapw;
         uint32_t                xs_blk_unmap;
@@ -59,21 +56,17 @@ struct __xfsstats {
         uint32_t                xs_del_exlist;
         uint32_t                xs_look_exlist;
         uint32_t                xs_cmp_exlist;
-# define XFSSTAT_END_BLOCK_MAP_BTREE    (XFSSTAT_END_BLOCK_MAPPING+4)
         uint32_t                xs_bmbt_lookup;
         uint32_t                xs_bmbt_compare;
         uint32_t                xs_bmbt_insrec;
         uint32_t                xs_bmbt_delrec;
-# define XFSSTAT_END_DIRECTORY_OPS      (XFSSTAT_END_BLOCK_MAP_BTREE+4)
         uint32_t                xs_dir_lookup;
         uint32_t                xs_dir_create;
         uint32_t                xs_dir_remove;
         uint32_t                xs_dir_getdents;
-# define XFSSTAT_END_TRANSACTIONS       (XFSSTAT_END_DIRECTORY_OPS+3)
         uint32_t                xs_trans_sync;
         uint32_t                xs_trans_async;
         uint32_t                xs_trans_empty;
-# define XFSSTAT_END_INODE_OPS          (XFSSTAT_END_TRANSACTIONS+7)
         uint32_t                xs_ig_attempts;
         uint32_t                xs_ig_found;
         uint32_t                xs_ig_frecycle;
@@ -81,13 +74,11 @@ struct __xfsstats {
         uint32_t                xs_ig_dup;
         uint32_t                xs_ig_reclaims;
         uint32_t                xs_ig_attrchg;
-# define XFSSTAT_END_LOG_OPS            (XFSSTAT_END_INODE_OPS+5)
         uint32_t                xs_log_writes;
         uint32_t                xs_log_blocks;
         uint32_t                xs_log_noiclogs;
         uint32_t                xs_log_force;
         uint32_t                xs_log_force_sleep;
-# define XFSSTAT_END_TAIL_PUSHING       (XFSSTAT_END_LOG_OPS+10)
         uint32_t                xs_try_logspace;
         uint32_t                xs_sleep_logspace;
         uint32_t                xs_push_ail;
@@ -98,22 +89,17 @@ struct __xfsstats {
         uint32_t                xs_push_ail_flushing;
         uint32_t                xs_push_ail_restarts;
         uint32_t                xs_push_ail_flush;
-# define XFSSTAT_END_WRITE_CONVERT      (XFSSTAT_END_TAIL_PUSHING+2)
         uint32_t                xs_xstrat_quick;
         uint32_t                xs_xstrat_split;
-# define XFSSTAT_END_READ_WRITE_OPS     (XFSSTAT_END_WRITE_CONVERT+2)
         uint32_t                xs_write_calls;
         uint32_t                xs_read_calls;
-# define XFSSTAT_END_ATTRIBUTE_OPS      (XFSSTAT_END_READ_WRITE_OPS+4)
         uint32_t                xs_attr_get;
         uint32_t                xs_attr_set;
         uint32_t                xs_attr_remove;
         uint32_t                xs_attr_list;
-# define XFSSTAT_END_INODE_CLUSTER      (XFSSTAT_END_ATTRIBUTE_OPS+3)
         uint32_t                xs_iflush_count;
         uint32_t                xs_icluster_flushcnt;
         uint32_t                xs_icluster_flushinode;
-# define XFSSTAT_END_VNODE_OPS          (XFSSTAT_END_INODE_CLUSTER+8)
         uint32_t                vn_active;      /* # vnodes not on free lists */
         uint32_t                vn_alloc;       /* # times vn_alloc called */
         uint32_t                vn_get;         /* # times vn_get called */
@@ -122,7 +108,6 @@ struct __xfsstats {
         uint32_t                vn_reclaim;     /* # times vn_reclaim called */
         uint32_t                vn_remove;      /* # times vn_remove called */
         uint32_t                vn_free;        /* # times vn_free called */
-#define XFSSTAT_END_BUF                 (XFSSTAT_END_VNODE_OPS+9)
         uint32_t                xb_get;
         uint32_t                xb_create;
         uint32_t                xb_get_locked;
@@ -133,28 +118,19 @@ struct __xfsstats {
         uint32_t                xb_page_found;
         uint32_t                xb_get_read;
 /* Version 2 btree counters */
-#define XFSSTAT_END_ABTB_V2             (XFSSTAT_END_BUF + __XBTS_MAX)
         uint32_t                xs_abtb_2[__XBTS_MAX];
-#define XFSSTAT_END_ABTC_V2             (XFSSTAT_END_ABTB_V2 + __XBTS_MAX)
         uint32_t                xs_abtc_2[__XBTS_MAX];
-#define XFSSTAT_END_BMBT_V2             (XFSSTAT_END_ABTC_V2 + __XBTS_MAX)
         uint32_t                xs_bmbt_2[__XBTS_MAX];
-#define XFSSTAT_END_IBT_V2              (XFSSTAT_END_BMBT_V2 + __XBTS_MAX)
         uint32_t                xs_ibt_2[__XBTS_MAX];
-#define XFSSTAT_END_FIBT_V2             (XFSSTAT_END_IBT_V2 + __XBTS_MAX)
         uint32_t                xs_fibt_2[__XBTS_MAX];
-#define XFSSTAT_END_RMAP_V2             (XFSSTAT_END_FIBT_V2 + __XBTS_MAX)
         uint32_t                xs_rmap_2[__XBTS_MAX];
-#define XFSSTAT_END_REFCOUNT            (XFSSTAT_END_RMAP_V2 + __XBTS_MAX)
         uint32_t                xs_refcbt_2[__XBTS_MAX];
-#define XFSSTAT_END_XQMSTAT             (XFSSTAT_END_REFCOUNT + 6)
         uint32_t                xs_qm_dqreclaims;
         uint32_t                xs_qm_dqreclaim_misses;
         uint32_t                xs_qm_dquot_dups;
         uint32_t                xs_qm_dqcachemisses;
         uint32_t                xs_qm_dqcachehits;
         uint32_t                xs_qm_dqwants;
-#define XFSSTAT_END_QM                  (XFSSTAT_END_XQMSTAT+2)
         uint32_t                xs_qm_dquot;
         uint32_t                xs_qm_dquot_unused;
 /* Extra precision counters */
@@ -163,10 +139,12 @@ struct __xfsstats {
         uint64_t                xs_read_bytes;
 };
 
+#define xfsstats_offset(f)      (offsetof(struct __xfsstats, f)/sizeof(uint32_t))
+
 struct xfsstats {
         union {
                 struct __xfsstats       s;
-                uint32_t                a[XFSSTAT_END_XQMSTAT];
+                uint32_t                a[xfsstats_offset(xs_qm_dquot)];
         };
 };