Index: sys/kern/subr_compressor.c
===================================================================
--- sys/kern/subr_compressor.c
+++ sys/kern/subr_compressor.c
@@ -66,8 +66,7 @@
 
 #ifdef GZIO
 
-#include <sys/gsb_crc32.h>
-#include <sys/zutil.h>
+#include <contrib/zlib/zlib.h>
 
 struct gz_stream {
 	uint8_t		*gz_buffer;	/* output buffer */
@@ -119,7 +118,7 @@
 	s->gz_stream.avail_in = 0;
 
 	error = deflateInit2(&s->gz_stream, level, Z_DEFLATED, -MAX_WBITS,
-	    DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+	    8, Z_DEFAULT_STRATEGY);
 	if (error != 0)
 		goto fail;
 
@@ -141,7 +140,7 @@
 
 	s = stream;
 	s->gz_off = 0;
-	s->gz_crc = ~0U;
+	s->gz_crc = crc32(0L, Z_NULL, 0);
 
 	(void)deflateReset(&s->gz_stream);
 	s->gz_stream.avail_out = s->gz_bufsz;
@@ -153,7 +152,7 @@
 	hdr[0] = 0x1f;
 	hdr[1] = 0x8b;
 	hdr[2] = Z_DEFLATED;
-	hdr[9] = OS_CODE;
+	hdr[9] = 0x03; /* zlib's OS_CODE Unix */
 	s->gz_stream.next_out += hdrlen;
 	s->gz_stream.avail_out -= hdrlen;
 }
@@ -173,9 +172,8 @@
 	if (len > 0) {
 		s->gz_stream.avail_in = len;
 		s->gz_stream.next_in = data;
-		s->gz_crc = crc32_raw(data, len, s->gz_crc);
-	} else
-		s->gz_crc ^= ~0U;
+		s->gz_crc = crc32(s->gz_crc, data, len);
+	}
 
 	error = 0;
 	do {