super-intel: don't mark structs 'packed' unnecessarily

[thirdparty/mdadm.git] / super-intel.c

diff --git a/super-intel.c b/super-intel.c
index 713058c7e4174b98fac734efadd2cb8dde348409..a7fbed4db7ef5ff362a385382c488e697e29d9e1 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -96,6 +96,19 @@
                                                   * mutliple PPL area
                                                   */
 
+/*
+ * This macro let's us ensure that no-one accidentally
+ * changes the size of a struct
+ */
+#define ASSERT_SIZE(_struct, size) \
+static inline void __assert_size_##_struct(void)       \
+{                                                      \
+       switch (0) {                                    \
+       case 0: break;                                  \
+       case (sizeof(struct _struct) == size): break;   \
+       }                                               \
+}
+
 /* Disk configuration info. */
 #define IMSM_MAX_DEVICES 255
 struct imsm_disk {
@@ -112,6 +125,7 @@ struct imsm_disk {
 #define        IMSM_DISK_FILLERS       3
        __u32 filler[IMSM_DISK_FILLERS]; /* 0xF5 - 0x107 MPB_DISK_FILLERS for future expansion */
 };
+ASSERT_SIZE(imsm_disk, 48)
 
 /* map selector for map managment
  */
@@ -146,7 +160,8 @@ struct imsm_map {
        __u32 disk_ord_tbl[1];  /* disk_ord_tbl[num_members],
                                 * top byte contains some flags
                                 */
-} __attribute__ ((packed));
+};
+ASSERT_SIZE(imsm_map, 52)
 
 struct imsm_vol {
        __u32 curr_migr_unit;
@@ -169,7 +184,8 @@ struct imsm_vol {
        __u32 filler[4];
        struct imsm_map map[1];
        /* here comes another one if migr_state */
-} __attribute__ ((packed));
+};
+ASSERT_SIZE(imsm_vol, 84)
 
 struct imsm_dev {
        __u8  volume[MAX_RAID_SERIAL_LEN];
@@ -220,7 +236,8 @@ struct imsm_dev {
 #define IMSM_DEV_FILLERS 3
        __u32 filler[IMSM_DEV_FILLERS];
        struct imsm_vol vol;
-} __attribute__ ((packed));
+};
+ASSERT_SIZE(imsm_dev, 164)
 
 struct imsm_super {
        __u8 sig[MAX_SIGNATURE_LENGTH]; /* 0x00 - 0x1F */
@@ -248,7 +265,8 @@ struct imsm_super {
        struct imsm_disk disk[1];       /* 0xD8 diskTbl[numDisks] */
        /* here comes imsm_dev[num_raid_devs] */
        /* here comes BBM logs */
-} __attribute__ ((packed));
+};
+ASSERT_SIZE(imsm_super, 264)
 
 #define BBM_LOG_MAX_ENTRIES 254
 #define BBM_LOG_MAX_LBA_ENTRY_VAL 256          /* Represents 256 LBAs */
@@ -269,7 +287,8 @@ struct bbm_log {
        __u32 signature; /* 0xABADB10C */
        __u32 entry_count;
        struct bbm_log_entry marked_block_entries[BBM_LOG_MAX_ENTRIES];
-} __attribute__ ((__packed__));
+};
+ASSERT_SIZE(bbm_log, 2040)
 
 static char *map_state_str[] = { "normal", "uninitialized", "degraded", "failed" };
 
@@ -323,7 +342,8 @@ struct migr_record {
                                       * destination - high order 32 bits */
        __u32 num_migr_units_hi;      /* Total num migration units-of-op
                                       * high order 32 bits */
-} __attribute__ ((__packed__));
+};
+ASSERT_SIZE(migr_record, 64)
 
 struct md_list {
        /* usage marker: