diff --git a/block/partitions/mac.c b/block/partitions/mac.c
index c80183156d68..b02530d98629 100644
--- a/block/partitions/mac.c
+++ b/block/partitions/mac.c
@@ -53,13 +53,25 @@ int mac_partition(struct parsed_partitions *state)
 	}
 	secsize = be16_to_cpu(md->block_size);
 	put_dev_sector(sect);
+
+	/*
+	 * If the "block size" is not a power of 2, things get weird - we might
+	 * end up with a partition straddling a sector boundary, so we wouldn't
+	 * be able to read a partition entry with read_part_sector().
+	 * Real block sizes are probably (?) powers of two, so just require
+	 * that.
+	 */
+	if (!is_power_of_2(secsize))
+		return -1;
 	datasize = round_down(secsize, 512);
 	data = read_part_sector(state, datasize / 512, &sect);
 	if (!data)
 		return -1;
 	partoffset = secsize % 512;
-	if (partoffset + sizeof(*part) > datasize)
+	if (partoffset + sizeof(*part) > datasize) {
+		put_dev_sector(sect);
 		return -1;
+	}
 	part = (struct mac_partition *) (data + partoffset);
 	if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) {
 		put_dev_sector(sect);
@@ -112,8 +124,8 @@ int mac_partition(struct parsed_partitions *state)
 				int i, l;
 
 				goodness++;
-				l = strlen(part->name);
-				if (strcmp(part->name, "/") == 0)
+				l = strnlen(part->name, sizeof(part->name));
+				if (strncmp(part->name, "/", sizeof(part->name)) == 0)
 					goodness++;
 				for (i = 0; i <= l - 4; ++i) {
 					if (strncasecmp(part->name + i, "root",
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 9ebb53f031cd..fa2a76cc2f73 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -861,12 +861,22 @@ static inline bool blk_mq_add_to_batch(struct request *req,
 				       void (*complete)(struct io_comp_batch *))
 {
 	/*
-	 * blk_mq_end_request_batch() can't end request allocated from
-	 * sched tags
+	 * Check various conditions that exclude batch processing:
+	 * 1) No batch container
+	 * 2) Has scheduler data attached
+	 * 3) Not a passthrough request and end_io set
+	 * 4) Not a passthrough request and an ioerror
 	 */
-	if (!iob || (req->rq_flags & RQF_SCHED_TAGS) || ioerror ||
-			(req->end_io && !blk_rq_is_passthrough(req)))
+	if (!iob)
 		return false;
+	if (req->rq_flags & RQF_SCHED_TAGS)
+		return false;
+	if (!blk_rq_is_passthrough(req)) {
+		if (req->end_io)
+			return false;
+		if (ioerror < 0)
+			return false;
+	}
 
 	if (!iob->complete)
 		iob->complete = complete;