[PATCH 18/24] scsi: Implement scsi_is_reserved_cmd()

[Hannes Reinecke]

Add function to check if a SCSI command originates from the reserved
command pool.

Signed-off-by: Hannes Reinecke <h...@suse.com>
---
 block/blk-mq.c          | 13 +++++++++++++
 include/linux/blk-mq.h  |  2 ++
 include/scsi/scsi_tcq.h | 10 +++++++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6711a61ba3b..a2212c117782 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -289,6 +289,19 @@ static inline bool blk_mq_need_time_stamp(struct request 
*rq)
        return (rq->rq_flags & RQF_IO_STAT) || rq->q->elevator;
 }
 
+/**
+ * blk_mq_rq_is_reserved - Check if a request has a reserved tag
+ *
+ * @rq: Request to check
+ */
+bool blk_mq_rq_is_reserved(struct request *rq)
+{
+       struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
+
+       return blk_mq_tag_is_reserved(hctx->tags, rq->tag);
+}
+EXPORT_SYMBOL_GPL(blk_mq_rq_is_reserved);
+
 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
                unsigned int tag, unsigned int op)
 {
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 15d1aa53d96c..e0e49f1c6f3c 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -348,6 +348,8 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq)
        return rq + 1;
 }
 
+bool blk_mq_rq_is_reserved(struct request *rq);
+
 #define queue_for_each_hw_ctx(q, hctx, i)                              \
        for ((i) = 0; (i) < (q)->nr_hw_queues &&                        \
             ({ hctx = (q)->queue_hw_ctx[i]; 1; }); (i)++)
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
index 227f3bd4e974..0c11e8fbe6d2 100644
--- a/include/scsi/scsi_tcq.h
+++ b/include/scsi/scsi_tcq.h
@@ -58,7 +58,15 @@ static inline void scsi_put_reserved_cmd(struct scsi_cmnd 
*scmd)
 {
        struct request *rq = blk_mq_rq_from_pdu(scmd);
 
-       blk_mq_free_request(rq);
+       if (blk_mq_rq_is_reserved(rq))
+               blk_mq_free_request(rq);
+}
+
+static inline bool scsi_is_reserved_cmd(struct scsi_cmnd *scmd)
+{
+       struct request *rq = blk_mq_rq_from_pdu(scmd);
+
+       return blk_mq_rq_is_reserved(rq);
 }
 
 #endif /* CONFIG_BLOCK */
-- 
2.16.4