block: remove CONFIG_DEBUG_BLOCK_EXT_DEVT

This might have been a neat debug aid when the extended dev_t was
added, but that time is long gone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210824075216.1179406-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 39 deletions

diff --git a/block/genhd.c b/block/genhd.c
index f13b7eb0238b..6a5b65c86c4b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -313,54 +313,19 @@ void unregister_blkdev(unsigned int major, const char *name)
 
 EXPORT_SYMBOL(unregister_blkdev);
 
-/**
- * blk_mangle_minor - scatter minor numbers apart
- * @minor: minor number to mangle
- *
- * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
- * is enabled.  Mangling twice gives the original value.
- *
- * RETURNS:
- * Mangled value.
- *
- * CONTEXT:
- * Don't care.
- */
-static int blk_mangle_minor(int minor)
-{
-#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
-	int i;
-
-	for (i = 0; i < MINORBITS / 2; i++) {
-		int low = minor & (1 << i);
-		int high = minor & (1 << (MINORBITS - 1 - i));
-		int distance = MINORBITS - 1 - 2 * i;
-
-		minor ^= low | high;	/* clear both bits */
-		low <<= distance;	/* swap the positions */
-		high >>= distance;
-		minor |= low | high;	/* and set */
-	}
-#endif
-	return minor;
-}
-
 int blk_alloc_ext_minor(void)
 {
 	int idx;
 
 	idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
-	if (idx < 0) {
-		if (idx == -ENOSPC)
-			return -EBUSY;
-		return idx;
-	}
-	return blk_mangle_minor(idx);
+	if (idx == -ENOSPC)
+		return -EBUSY;
+	return idx;
 }
 
 void blk_free_ext_minor(unsigned int minor)
 {
-	ida_free(&ext_devt_ida, blk_mangle_minor(minor));
+	ida_free(&ext_devt_ida, minor);
 }
 
 static char *bdevt_str(dev_t devt, char *buf)