improve byteswap logic

Signed-off-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>

Author: Paul Dagnelie

include/sys/vdev_anyraid.h

@@ -216,6 +216,30 @@ typedef struct anyraid_map_entry {
 	} ame_u;
 } anyraid_map_entry_t;
 
+static inline void
+ame_byteswap(anyraid_map_entry_t *ame)
+{
+	uint8_t type = ame->ame_u.ame_amle.amle_type;
+	switch (type) {
+		case AMET_SKIP: {
+			anyraid_map_skip_entry_t *amse =
+			    &ame->ame_u.ame_amse;
+			amse->amse_u.amse_skip_count =
+			    BSWAP_32(amse_get_skip_count(amse)) >> NBBY;
+			amse->amse_u.amse_type = AMET_SKIP;
+			break;
+		}
+		case AMET_LOC: {
+			anyraid_map_loc_entry_t *amle =
+			    &ame->ame_u.ame_amle;
+			amle->amle_offset = BSWAP_16(amle->amle_offset);
+			break;
+		}
+		default:
+			PANIC("Invalid entry type %d", type);
+	}
+}
+
 #define	VDEV_ANYRAID_MAX_DISKS	(1 << 8)
 #define	VDEV_ANYRAID_MAX_TPD	(1 << 16)
 #define	VDEV_ANYRAID_MAX_TILES	(VDEV_ANYRAID_MAX_DISKS * VDEV_ANYRAID_MAX_TPD)

module/zfs/vdev_anyraid.c

@@ -459,6 +459,16 @@ vdev_anyraid_pick_best_mapping(vdev_t *cvd, uint64_t *out_txg,
 	return (error);
 }
 
+#ifdef _ZFS_BIG_ENDIAN
+static void
+byteswap_map_buf(void *buf, uint32_t length)
+{
+	for (size_t i = 0; i < length; i += sizeof (anyraid_map_entry_t)) {
+		ame_byteswap((anyraid_map_entry_t *)((char *)buf + i));
+	}
+}
+#endif
+
 static int
 anyraid_open_existing(vdev_t *vd, uint64_t child, uint16_t **child_capacities)
 {
@@ -596,8 +606,8 @@ anyraid_open_existing(vdev_t *vd, uint64_t child, uint16_t **child_capacities)
 #ifdef _ZFS_BIG_ENDIAN
 			uint32_t length = map_length -
 			    next_map * SPA_MAXBLOCKSIZE;
-			byteswap_uint32_array(map_buf, length <
-			    SPA_MAXBLOCKSIZE ? length : SPA_MAXBLOCKSIZE);
+			byteswap_map_buf(map_buf, (uint32_t)(length <
+			    SPA_MAXBLOCKSIZE ? length : SPA_MAXBLOCKSIZE));
 #endif
 		}
 		anyraid_map_entry_t *entry =
@@ -1256,7 +1266,9 @@ map_write_issue(zio_t *zio, vdev_t *vd, uint64_t base_offset,
     int flags)
 {
 #ifdef _ZFS_BIG_ENDIAN
-	byteswap_uint32_array(abd, length);
+	void *buf = abd_borrow_buf(abd, SPA_MAXBLOCKSIZE);
+	byteswap_map_buf(buf, length);
+	abd_return_buf(abd, buf, SPA_MAXBLOCKSIZE);
 #else
 	(void) length;
 #endif