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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /include/scsi/scsi_tcq.h
Initial import
Diffstat (limited to 'include/scsi/scsi_tcq.h')
-rw-r--r--include/scsi/scsi_tcq.h101
1 files changed, 101 insertions, 0 deletions
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
new file mode 100644
index 000000000..b27977e8a
--- /dev/null
+++ b/include/scsi/scsi_tcq.h
@@ -0,0 +1,101 @@
+#ifndef _SCSI_SCSI_TCQ_H
+#define _SCSI_SCSI_TCQ_H
+
+#include <linux/blkdev.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+#define SCSI_NO_TAG (-1) /* identify no tag in use */
+
+
+#ifdef CONFIG_BLOCK
+static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
+ int unique_tag)
+{
+ u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
+ struct request *req = NULL;
+
+ if (hwq < shost->tag_set.nr_hw_queues)
+ req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
+ blk_mq_unique_tag_to_tag(unique_tag));
+ return req ? (struct scsi_cmnd *)req->special : NULL;
+}
+
+/**
+ * scsi_find_tag - find a tagged command by device
+ * @SDpnt: pointer to the ScSI device
+ * @tag: tag generated by blk_mq_unique_tag()
+ *
+ * Notes:
+ * Only works with tags allocated by the generic blk layer.
+ **/
+static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
+{
+ struct request *req;
+
+ if (tag != SCSI_NO_TAG) {
+ if (shost_use_blk_mq(sdev->host))
+ return scsi_mq_find_tag(sdev->host, tag);
+
+ req = blk_queue_find_tag(sdev->request_queue, tag);
+ return req ? (struct scsi_cmnd *)req->special : NULL;
+ }
+
+ /* single command, look in space */
+ return sdev->current_cmnd;
+}
+
+
+/**
+ * scsi_init_shared_tag_map - create a shared tag map
+ * @shost: the host to share the tag map among all devices
+ * @depth: the total depth of the map
+ */
+static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
+{
+ /*
+ * We always have a shared tag map around when using blk-mq.
+ */
+ if (shost_use_blk_mq(shost))
+ return 0;
+
+ /*
+ * If the shared tag map isn't already initialized, do it now.
+ * This saves callers from having to check ->bqt when setting up
+ * devices on the shared host (for libata)
+ */
+ if (!shost->bqt) {
+ shost->bqt = blk_init_tags(depth,
+ shost->hostt->tag_alloc_policy);
+ if (!shost->bqt)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * scsi_host_find_tag - find the tagged command by host
+ * @shost: pointer to scsi_host
+ * @tag: tag generated by blk_mq_unique_tag()
+ *
+ * Notes:
+ * Only works with tags allocated by the generic blk layer.
+ **/
+static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
+ int tag)
+{
+ struct request *req;
+
+ if (tag != SCSI_NO_TAG) {
+ if (shost_use_blk_mq(shost))
+ return scsi_mq_find_tag(shost, tag);
+ req = blk_map_queue_find_tag(shost->bqt, tag);
+ return req ? (struct scsi_cmnd *)req->special : NULL;
+ }
+ return NULL;
+}
+
+#endif /* CONFIG_BLOCK */
+#endif /* _SCSI_SCSI_TCQ_H */