From 626dd7a5fe357db391cc417521a265148201cf1d Mon Sep 17 00:00:00 2001
From: Dave Wysochanski <dwysocha@redhat.com>
Date: Mon, 23 Jun 2008 14:54:50 +0000
Subject: [PATCH] Suppress 'sb_offset' compiler warning by using enum for md
 superblock versions.

The warning is bogus and is only seen on certain versions of gcc.
However using the enum does seem to clarify the intent of the code - only
3 possible md minor superblock versions.

Related compiler warning:
device/dev-md.c:53: warning: 'sb_offset' may be used uninitialized in this function
---
 WHATS_NEW           |  1 +
 lib/device/dev-md.c | 21 +++++++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/WHATS_NEW b/WHATS_NEW
index 56cd14c3b..57f835eac 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.39 -
 ================================
+  Suppress 'sb_offset' compiler warning by using enum for md minor sb version. 
   lvm2_run: Don't return uninitialized "ret" for _memlock_inc or _memlock_dec.
   Avoid link failure when configuring without --enable-cmdlib.
   Avoid link failure when configuring without --enable-readline.
diff --git a/lib/device/dev-md.c b/lib/device/dev-md.c
index ed897031d..adacf0bc3 100644
--- a/lib/device/dev-md.c
+++ b/lib/device/dev-md.c
@@ -48,18 +48,26 @@ static int _dev_has_md_magic(struct device *dev, uint64_t sb_offset)
  * 1: At start of device
  * 2: 4K from start of device.
  */
-static uint64_t _v1_sb_offset(uint64_t size, unsigned minor_version)
+typedef enum {
+	MD_MINOR_VERSION_MIN,
+	MD_MINOR_V0 = MD_MINOR_VERSION_MIN,
+	MD_MINOR_V1,
+	MD_MINOR_V2,
+	MD_MINOR_VERSION_MAX = MD_MINOR_V2
+} md_minor_version_t;
+
+static uint64_t _v1_sb_offset(uint64_t size, md_minor_version_t minor_version)
 {
 	uint64_t sb_offset;
 
 	switch(minor_version) {
-	case 0:
+	case MD_MINOR_V0:
 		sb_offset = (size - 8 * 2) & ~(4 * 2 - 1ULL);
 		break;
-	case 1:
+	case MD_MINOR_V1:
 		sb_offset = 0;
 		break;
-	case 2:
+	case MD_MINOR_V2:
 		sb_offset = 4 * 2;
 		break;
 	}
@@ -74,7 +82,7 @@ static uint64_t _v1_sb_offset(uint64_t size, unsigned minor_version)
 int dev_is_md(struct device *dev, uint64_t *sb)
 {
 	int ret = 1;
-	unsigned minor = 0;
+	md_minor_version_t minor;
 	uint64_t size, sb_offset;
 
 	if (!dev_get_size(dev, &size)) {
@@ -96,12 +104,13 @@ int dev_is_md(struct device *dev, uint64_t *sb)
 	if (_dev_has_md_magic(dev, sb_offset))
 		goto out;
 
+	minor = MD_MINOR_VERSION_MIN;
 	/* Version 1, try v1.0 -> v1.2 */
 	do {
 		sb_offset = _v1_sb_offset(size, minor);
 		if (_dev_has_md_magic(dev, sb_offset))
 			goto out;
-	} while (++minor <= 2);
+	} while (++minor <= MD_MINOR_VERSION_MAX);
 
 	ret = 0;