From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 10 Jul 2018 22:52:16 +0000 (-0600)
Subject: axmap: ensure that overlaps are handled strictly sequential
X-Git-Tag: fio-3.8~17
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=8cd5a2fdad69fcc7acc85863b69cc9ded97edceb

axmap: ensure that overlaps are handled strictly sequential

We must terminate at the first overlapping bit, we can't
just mask off non-sequential ranges.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/lib/axmap.c b/lib/axmap.c
index 3c65308c..c29597f8 100644
--- a/lib/axmap.c
+++ b/lib/axmap.c
@@ -234,17 +234,18 @@ static bool axmap_set_fn(struct axmap_level *al, unsigned long offset,
 	if (overlap == mask)
 		return true;
 
-	while (overlap) {
-		unsigned long clear_mask = ~(1UL << ffz(~overlap));
+	if (overlap) {
+		const int __bit = ffz(~overlap);
 
-		mask &= clear_mask;
-		overlap &= clear_mask;
-		nr_bits--;
+		if (__bit == bit)
+			return true;
+
+		nr_bits = __bit - bit;
+		mask = bit_masks[nr_bits] << bit;
 	}
 
 	assert(mask);
 	assert(!(al->map[offset] & mask));
-		
 	al->map[offset] |= mask;
 
 	if (!al->level)