[PATCH RFC v3 05/22] scsi: core: Add support for reserved command timeout handling

[John Garry]

Add support for reserved timeout handling. Any driver which specifies
that it supports reserved tags must supply a handler.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 drivers/scsi/hosts.c      | 15 +++++++++++----
 drivers/scsi/scsi_error.c |  3 +++
 include/scsi/scsi_host.h  |  1 +
 3 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 78968553089f..52346085b3c1 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -230,10 +230,17 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 		goto fail;
 	}
 
-	if (shost->nr_reserved_cmds && !sht->reserved_queuecommand) {
-		shost_printk(KERN_ERR, shost,
-			"nr_reserved_cmds set but no method to queue\n");
-		goto fail;
+	if (shost->nr_reserved_cmds) {
+		if (!sht->reserved_queuecommand) {
+			shost_printk(KERN_ERR, shost,
+				"nr_reserved_cmds set but no method to queue\n");
+			goto fail;
+		}
+		if (!sht->reserved_timedout) {
+			shost_printk(KERN_ERR, shost,
+				"nr_reserved_cmds set but no method to handle timeouts\n");
+			goto fail;
+		}
 	}
 
 	/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 6995c8979230..2f86a4284f29 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -338,6 +338,9 @@ enum blk_eh_timer_return scsi_timeout(struct request *req)
 	if (host->eh_deadline != -1 && !host->last_reset)
 		host->last_reset = jiffies;
 
+	if (blk_mq_is_reserved_rq(req))
+		return host->hostt->reserved_timedout(scmd);
+
 	if (host->hostt->eh_timed_out)
 		rtn = host->hostt->eh_timed_out(scmd);
 
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index a39f36aa0b0d..266c13e731de 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -74,6 +74,7 @@ struct scsi_host_template {
 	 */
 	int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
 	int (*reserved_queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
+	enum blk_eh_timer_return (*reserved_timedout)(struct scsi_cmnd *);
 
 	/*
 	 * The commit_rqs function is used to trigger a hardware
-- 
2.35.3