raid: rework _raid_target_present()

Recently added check for reshaping in this function called for
a cleanup to avoid proliferating it with more explicit conditionals.

Base the reshaping check on the given _features array.

Related: rhbz834579
Related: rhbz1191935
Related: rhbz1191978

1 files changed, 29 insertions, 14 deletions

diff --git a/lib/raid/raid.c b/lib/raid/raid.c
index 68154540e..6439a3e1c 100644
--- a/lib/raid/raid.c
+++ b/lib/raid/raid.c
@@ -448,19 +448,32 @@ out:
 	return r;
 }
 
+/* Define raid feature based on the tuple(major, minor, patchlevel) of raid target */
+struct raid_feature {
+	uint32_t maj;
+	uint32_t min;
+	uint32_t patchlevel;
+	unsigned raid_feature;
+	const char *feature;
+};
+
+/* Return true if tuple(@maj, @min, @patchlevel) is greater/equal to @*feature members */
+static int _check_feature(const struct raid_feature *feature, uint32_t maj, uint32_t min, uint32_t patchlevel)
+{
+	return (maj > feature->maj) ||
+	       (maj == feature->maj && min >= feature->min) ||
+	       (maj == feature->maj && min == feature->min && patchlevel >= feature->patchlevel);
+}
+
 static int _raid_target_present(struct cmd_context *cmd,
 				const struct lv_segment *seg __attribute__((unused)),
 				unsigned *attributes)
 {
 	/* List of features with their kernel target version */
-	static const struct feature {
-		uint32_t maj;
-		uint32_t min;
-		unsigned raid_feature;
-		const char *feature;
-	} _features[] = {
-		{ 1, 3, RAID_FEATURE_RAID10, SEG_TYPE_NAME_RAID10 },
-		{ 1, 7, RAID_FEATURE_RAID0, SEG_TYPE_NAME_RAID0 },
+	const struct raid_feature _features[] = {
+		{ 1, 3, 0, RAID_FEATURE_RAID10, SEG_TYPE_NAME_RAID10 },
+		{ 1, 7, 0, RAID_FEATURE_RAID0, SEG_TYPE_NAME_RAID0 },
+		{ 1, 10, 1, RAID_FEATURE_RESHAPE, "reshaping" },
 	};
 
 	static int _raid_checked = 0;
@@ -482,22 +495,24 @@ static int _raid_target_present(struct cmd_context *cmd,
 			return_0;
 
 		for (i = 0; i < DM_ARRAY_SIZE(_features); ++i)
-			if ((maj > _features[i].maj) ||
-			    (maj == _features[i].maj && min >= _features[i].min))
+			if (_check_feature(_features + i, maj, min, patchlevel))
 				_raid_attrs |= _features[i].raid_feature;
 			else
 				log_very_verbose("Target raid does not support %s.",
 						 _features[i].feature);
 
+		/*
+		 * Seperate check for proper raid4 mapping supported
+		 *
+		 * If we get more of these range checks, avoid them
+		 * altogether by enhancing 'struct raid_feature'
+		 * and _check_feature() to handle them.
+		 */
 		if (!(maj == 1 && (min == 8 || (min == 9 && patchlevel == 0))))
 			_raid_attrs |= RAID_FEATURE_RAID4;
 		else
 			log_very_verbose("Target raid does not support %s.",
 					 SEG_TYPE_NAME_RAID4);
-
-		if (maj > 1 ||
-		    (maj == 1 && (min > 10 || (min == 10 && patchlevel >= 1))))
-			_raid_attrs |= RAID_FEATURE_RESHAPE;
 	}
 
 	if (attributes)