[PATCH 1/7] xz: add fall-through comments to a switch statement

[Jan Beulich <jbeulich@suse.com>]

From: Lasse Collin <lasse.collin@tukaani.org>

It's good style. I was also told that GCC 7 is more strict and might
give a warning when such comments are missing.

Suggested-by: Andrei Borzenkov <arvidjaar@gmail.com>
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
[Linux commit: 5a244f48ecbbd03a11eb84819c5c599db81823ee]
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
Linux has meanwhile further moved to using the "fallthrough" pseudo-
keyword, but us doing so requires the tool stack to first make this
available for use in at least stubdom builds.

--- a/xen/common/xz/dec_stream.c
+++ b/xen/common/xz/dec_stream.c
@@ -583,6 +583,8 @@ static enum xz_ret __init dec_main(struc
 			if (ret != XZ_OK)
 				return ret;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_START:
 			/* We need one byte of input to continue. */
 			if (b->in_pos == b->in_size)
@@ -606,6 +608,8 @@ static enum xz_ret __init dec_main(struc
 			s->temp.pos = 0;
 			s->sequence = SEQ_BLOCK_HEADER;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_HEADER:
 			if (!fill_temp(s, b))
 				return XZ_OK;
@@ -616,6 +620,8 @@ static enum xz_ret __init dec_main(struc
 
 			s->sequence = SEQ_BLOCK_UNCOMPRESS;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_UNCOMPRESS:
 			ret = dec_block(s, b);
 			if (ret != XZ_STREAM_END)
@@ -623,6 +629,8 @@ static enum xz_ret __init dec_main(struc
 
 			s->sequence = SEQ_BLOCK_PADDING;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_PADDING:
 			/*
 			 * Size of Compressed Data + Block Padding
@@ -643,6 +651,8 @@ static enum xz_ret __init dec_main(struc
 
 			s->sequence = SEQ_BLOCK_CHECK;
 
+		/* Fall through */
+
 		case SEQ_BLOCK_CHECK:
 			if (s->check_type == XZ_CHECK_CRC32) {
 				ret = crc32_validate(s, b);
@@ -665,6 +675,8 @@ static enum xz_ret __init dec_main(struc
 
 			s->sequence = SEQ_INDEX_PADDING;
 
+		/* Fall through */
+
 		case SEQ_INDEX_PADDING:
 			while ((s->index.size + (b->in_pos - s->in_start))
 					& 3) {
@@ -687,6 +699,8 @@ static enum xz_ret __init dec_main(struc
 
 			s->sequence = SEQ_INDEX_CRC32;
 
+		/* Fall through */
+
 		case SEQ_INDEX_CRC32:
 			ret = crc32_validate(s, b);
 			if (ret != XZ_STREAM_END)
@@ -695,6 +709,8 @@ static enum xz_ret __init dec_main(struc
 			s->temp.size = STREAM_HEADER_SIZE;
 			s->sequence = SEQ_STREAM_FOOTER;
 
+		/* Fall through */
+
 		case SEQ_STREAM_FOOTER:
 			if (!fill_temp(s, b))
 				return XZ_OK;