From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 23 Jan 2013 17:15:05 +0000 (-0700)
Subject: axmap: fix bug in axmap_find_first_free()
X-Git-Tag: fio-2.0.14~102
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=55348b420e618b1c5c50106261437fe948ef2132

axmap: fix bug in axmap_find_first_free()

If the map is completely full, we could return an invalid value
for the first free bit. So check if we actually found a match,
return failure if we didn't.

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

diff --git a/lib/axmap.c b/lib/axmap.c
index d9ad30bf..7351e297 100644
--- a/lib/axmap.c
+++ b/lib/axmap.c
@@ -309,7 +309,7 @@ static uint64_t axmap_find_first_free(struct axmap *axmap, unsigned int level,
 				       uint64_t index)
 {
 	unsigned long j;
-	int i;
+	int i, found = 0;
 
 	/*
 	 * Start at the bottom, then converge towards first free bit at the top
@@ -331,11 +331,12 @@ static uint64_t axmap_find_first_free(struct axmap *axmap, unsigned int level,
 			 * free bit at the next higher level
 			 */
 			index = (j << UNIT_SHIFT) + ffz(al->map[j]);
+			found = 1;
 			break;
 		}
 	}
 
-	return index;
+	return found ? index : (uint64_t) -1ULL;
 }
 
 uint64_t axmap_first_free(struct axmap *axmap)