ANDROID: block: Do not set the I/O priority for zoned writes

The I/O priority set by the ionice command or by the blk-ioprio cgroup
policy may cause the mq-deadline I/O scheduler to submit zoned writes in
the wrong order and hence to trigger unaligned write errors. Fix this by
not applying these I/O priority policies on sequential zoned writes.

Bug: 269471019
Bug: 415836627
Change-Id: I88ae04b697239f1aa27404cbf35c5a96d3a73a1f
Signed-off-by: Bart Van Assche <bvanassche@google.com>

block/blk-core.c

@@ -882,8 +882,41 @@ end_io:
 }
 EXPORT_SYMBOL(submit_bio_noacct);
 
+#ifdef CONFIG_BLK_DEV_ZONED
+/**
+ * blk_bio_is_seq_zoned_write() - Check if @bio requires write serialization.
+ * @bio: Bio to examine.
+ *
+ * Note: REQ_OP_ZONE_APPEND bios do not require serialization.
+ * Note: this function treats conventional zones on a zoned block device as
+ *   sequential zones. This is fine since zoned UFS devices have no conventional
+ *   zones.
+ */
+static bool blk_bio_is_seq_zoned_write(struct bio *bio)
+{
+	if (!bdev_is_zoned(bio->bi_bdev))
+		return false;
+
+	return bio_op(bio) == REQ_OP_WRITE ||
+		bio_op(bio) == REQ_OP_WRITE_ZEROES;
+}
+#else
+static bool blk_bio_is_seq_zoned_write(struct bio *bio)
+{
+	return false;
+}
+#endif
+
 static void bio_set_ioprio(struct bio *bio)
 {
+	/*
+	 * Do not set the I/O priority of sequential zoned write bios because
+	 * this could lead to reordering by the mq-deadline I/O scheduler and
+	 * hence to unaligned write errors.
+	 */
+	if (blk_bio_is_seq_zoned_write(bio))
+		return;
+
 	/* Nobody set ioprio so far? Initialize it based on task's nice value */
 	if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
 		bio->bi_ioprio = get_current_ioprio();