[PATCH v2 08/41] disk: part_dos: Fix a NULL pointer error

[Simon Glass]

When ext is NULL we cannot dereference it. Update the code flow to avoid
this, so that layout_mbr_partitions() can be used with partition tables
that do not include an extended partition.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

(no changes since v1)

 disk/part_dos.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/disk/part_dos.c b/disk/part_dos.c
index 9e29aa6583a..94fae7166d7 100644
--- a/disk/part_dos.c
+++ b/disk/part_dos.c
@@ -459,10 +459,12 @@ int layout_mbr_partitions(struct disk_partition *p, int count,
 			ext = &p[i];
 	}
 
-	if (i >= 4 && !ext) {
-		printf("%s: extended partition is needed for more than 4 partitions\n",
-		        __func__);
-		return -1;
+	if (count < 4)
+		return 0;
+
+	if (!ext) {
+		log_err("extended partition is needed for more than 4 partitions\n");
+		return -EINVAL;
 	}
 
 	/* calculate extended volumes start and size if needed */
-- 
2.33.0.1079.g6e70778dc9-goog