Add a method to queue reserved commands.
TODO:
- fix timeout handler to call into reserved commands
- We don't clear host_scribble for libata qc, but we should be able to drop
this if we store libata qc in the scsi cmnd priv_data
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
drivers/scsi/hosts.c | 6 ++++++
drivers/scsi/scsi_lib.c | 32 ++++++++++++++++++++++++++++++++
include/scsi/scsi_cmnd.h | 5 +++++
include/scsi/scsi_host.h | 1 +
4 files changed, 44 insertions(+)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 27296addaf63..5c9b05a8fec8 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -221,6 +221,12 @@ 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;
+ }
+
/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
shost->can_queue);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f6e53c6d913c..8c8b4c6767d9 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1422,6 +1422,16 @@ static void scsi_complete(struct request *rq)
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
enum scsi_disposition disposition;
+ if (scsi_is_reserved_cmd(cmd)) {
+ struct scsi_device *sdev = cmd->device;
+
+ scsi_mq_uninit_cmd(cmd);
+ scsi_device_unbusy(sdev, cmd);
+ __blk_mq_end_request(rq, 0);
+
+ return;
+ }
+
INIT_LIST_HEAD(&cmd->eh_entry);
atomic_inc(&cmd->device->iodone_cnt);
@@ -1706,6 +1716,28 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
WARN_ON_ONCE(cmd->budget_token < 0);
+ if (scsi_is_reserved_cmd(cmd)) {
+ unsigned char *host_scribble = cmd->host_scribble;
+
+ if (!(req->rq_flags & RQF_DONTPREP)) {
+ ret = scsi_prepare_cmd(req);
+ if (ret != BLK_STS_OK) {
+
+ goto out_dec_host_busy;
+ }
+
+ req->rq_flags |= RQF_DONTPREP;
+ } else {
+ clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
+ }
+
+ cmd->host_scribble = host_scribble;
+
+ blk_mq_start_request(req);
+
+ return shost->hostt->reserved_queuecommand(shost, cmd);
+ }
+
/*
* If the device is not in running state we will reject some or all
* commands.
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 1e80e70dfa92..e47df5836070 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -152,6 +152,11 @@ static inline void *scsi_cmd_priv(struct scsi_cmnd *cmd)
return cmd + 1;
}
+static inline bool scsi_is_reserved_cmd(struct scsi_cmnd *cmd)
+{
+ return blk_mq_is_reserved_rq(scsi_cmd_to_rq(cmd));
+}
+
void scsi_done(struct scsi_cmnd *cmd);
void scsi_done_direct(struct scsi_cmnd *cmd);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 149dcbd4125e..88c8504395c8 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -73,6 +73,7 @@ struct scsi_host_template {
* STATUS: REQUIRED
*/
int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
+ int (* reserved_queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
/*
* The commit_rqs function is used to trigger a hardware
--
2.26.2
