[PATCH v5 03/28] scsi: core: Make the budget map optional

[Bart Van Assche <bvanassche@acm.org>]

Prepare for not allocating a budget map for pseudo SCSI devices by
checking whether a budget map has been allocated before using it.

Cc: Hannes Reinecke <hare@suse.de>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi.c       | 5 +++++
 drivers/scsi/scsi_error.c | 3 +++
 drivers/scsi/scsi_lib.c   | 9 +++++++--
 drivers/scsi/scsi_scan.c  | 3 +++
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 9a0f467264b3..a9d3e0242555 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -216,6 +216,9 @@ int scsi_device_max_queue_depth(struct scsi_device *sdev)
  */
 int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
 {
+	if (WARN_ON_ONCE(!sdev->budget_map.map))
+		return -EINVAL;
+
 	depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
 
 	if (depth > 0) {
@@ -255,6 +258,8 @@ EXPORT_SYMBOL(scsi_change_queue_depth);
  */
 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
 {
+	if (!sdev->budget_map.map)
+		return 0;
 
 	/*
 	 * Don't let QUEUE_FULLs on the same
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 746ff6a1f309..87636068cd37 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -749,6 +749,9 @@ static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
 	const struct scsi_host_template *sht = sdev->host->hostt;
 	struct scsi_device *tmp_sdev;
 
+	if (!sdev->budget_map.map)
+		return;
+
 	if (!sht->track_queue_depth ||
 	    sdev->queue_depth >= sdev->max_queue_depth)
 		return;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9c67e04265ce..8d711f6d8959 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -396,7 +396,8 @@ void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
 	if (starget->can_queue > 0)
 		atomic_dec(&starget->target_busy);
 
-	sbitmap_put(&sdev->budget_map, cmd->budget_token);
+	if (sdev->budget_map.map)
+		sbitmap_put(&sdev->budget_map, cmd->budget_token);
 	cmd->budget_token = -1;
 }
 
@@ -1360,6 +1361,9 @@ static inline int scsi_dev_queue_ready(struct request_queue *q,
 {
 	int token;
 
+	if (!sdev->budget_map.map)
+		return INT_MAX;
+
 	token = sbitmap_get(&sdev->budget_map);
 	if (token < 0)
 		return -1;
@@ -1749,7 +1753,8 @@ static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
 {
 	struct scsi_device *sdev = q->queuedata;
 
-	sbitmap_put(&sdev->budget_map, budget_token);
+	if (sdev->budget_map.map)
+		sbitmap_put(&sdev->budget_map, budget_token);
 }
 
 /*
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index de039efef290..3267b36a6059 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -225,6 +225,9 @@ static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
 	int ret;
 	struct sbitmap sb_backup;
 
+	if (WARN_ON_ONCE(!sdev->budget_map.map))
+		return -EINVAL;
+
 	depth = min_t(unsigned int, depth, scsi_device_max_queue_depth(sdev));
 
 	/*