xfs: convert RUI log formats to use variable length arrays

Use variable length array declarations for RUI log items,
and replace the open coded sizeof formulae with a single function.

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

4 files changed, 28 insertions, 31 deletions

diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index a6eed43fa7cd..fc5eef85d61e 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -647,9 +647,17 @@ struct xfs_rui_log_format {
         __uint16_t              rui_size;       /* size of this item */
         __uint32_t              rui_nextents;   /* # extents to free */
         __uint64_t              rui_id;         /* rui identifier */
-        struct xfs_map_extent   rui_extents[1]; /* array of extents to rmap */
+        struct xfs_map_extent   rui_extents[];  /* array of extents to rmap */
 };
 
+static inline size_t
+xfs_rui_log_format_sizeof(
+        unsigned int            nr)
+{
+        return sizeof(struct xfs_rui_log_format) +
+                        nr * sizeof(struct xfs_map_extent);
+}
+
 /*
  * This is the structure used to lay out an rud log item in the
  * log.  The rud_extents array is a variable size array whose
diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
index 2500f28689d5..0432a459871c 100644
--- a/fs/xfs/xfs_rmap_item.c
+++ b/fs/xfs/xfs_rmap_item.c
@@ -51,28 +51,16 @@ xfs_rui_item_free(
                 kmem_zone_free(xfs_rui_zone, ruip);
 }
 
-/*
- * This returns the number of iovecs needed to log the given rui item.
- * We only need 1 iovec for an rui item.  It just logs the rui_log_format
- * structure.
- */
-static inline int
-xfs_rui_item_sizeof(
-        struct xfs_rui_log_item *ruip)
-{
-        return sizeof(struct xfs_rui_log_format) +
-                        (ruip->rui_format.rui_nextents - 1) *
-                        sizeof(struct xfs_map_extent);
-}
-
 STATIC void
 xfs_rui_item_size(
         struct xfs_log_item     *lip,
         int                     *nvecs,
         int                     *nbytes)
 {
+        struct xfs_rui_log_item *ruip = RUI_ITEM(lip);
+
         *nvecs += 1;
-        *nbytes += xfs_rui_item_sizeof(RUI_ITEM(lip));
+        *nbytes += xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents);
 }
 
 /*
@@ -97,7 +85,7 @@ xfs_rui_item_format(
         ruip->rui_format.rui_size = 1;
 
         xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_RUI_FORMAT, &ruip->rui_format,
-                        xfs_rui_item_sizeof(ruip));
+                        xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents));
 }
 
 /*
@@ -205,16 +193,12 @@ xfs_rui_init(
 
 {
         struct xfs_rui_log_item         *ruip;
-        uint                            size;
 
         ASSERT(nextents > 0);
-        if (nextents > XFS_RUI_MAX_FAST_EXTENTS) {
-                size = (uint)(sizeof(struct xfs_rui_log_item) +
-                        ((nextents - 1) * sizeof(struct xfs_map_extent)));
-                ruip = kmem_zalloc(size, KM_SLEEP);
-        } else {
+        if (nextents > XFS_RUI_MAX_FAST_EXTENTS)
+                ruip = kmem_zalloc(xfs_rui_log_item_sizeof(nextents), KM_SLEEP);
+        else
                 ruip = kmem_zone_zalloc(xfs_rui_zone, KM_SLEEP);
-        }
 
         xfs_log_item_init(mp, &ruip->rui_item, XFS_LI_RUI, &xfs_rui_item_ops);
         ruip->rui_format.rui_nextents = nextents;
@@ -239,14 +223,12 @@ xfs_rui_copy_format(
         uint                            len;
 
         src_rui_fmt = buf->i_addr;
-        len = sizeof(struct xfs_rui_log_format) +
-                        (src_rui_fmt->rui_nextents - 1) *
-                        sizeof(struct xfs_map_extent);
+        len = xfs_rui_log_format_sizeof(src_rui_fmt->rui_nextents);
 
         if (buf->i_len != len)
                 return -EFSCORRUPTED;
 
-        memcpy((char *)dst_rui_fmt, (char *)src_rui_fmt, len);
+        memcpy(dst_rui_fmt, src_rui_fmt, len);
         return 0;
 }
 
diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_item.h
index aefcc3a318a5..340c968e1f9c 100644
--- a/fs/xfs/xfs_rmap_item.h
+++ b/fs/xfs/xfs_rmap_item.h
@@ -70,6 +70,14 @@ struct xfs_rui_log_item {
         struct xfs_rui_log_format       rui_format;
 };
 
+static inline size_t
+xfs_rui_log_item_sizeof(
+        unsigned int            nr)
+{
+        return offsetof(struct xfs_rui_log_item, rui_format) +
+                        xfs_rui_log_format_sizeof(nr);
+}
+
 /*
  * This is the "rmap update done" log item.  It is used to log the fact that
  * some rmapbt updates mentioned in an earlier rui item have been performed.
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index fd6be45b3a1e..340975392e91 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1782,9 +1782,8 @@ xfs_init_zones(void)
         if (!xfs_rud_zone)
                 goto out_destroy_icreate_zone;
 
-        xfs_rui_zone = kmem_zone_init((sizeof(struct xfs_rui_log_item) +
-                        ((XFS_RUI_MAX_FAST_EXTENTS - 1) *
-                                sizeof(struct xfs_map_extent))),
+        xfs_rui_zone = kmem_zone_init(
+                        xfs_rui_log_item_sizeof(XFS_RUI_MAX_FAST_EXTENTS),
                         "xfs_rui_item");
         if (!xfs_rui_zone)
                 goto out_destroy_rud_zone;