On 11/04/2014 08:54 AM, Christoph Hellwig wrote:
> Currently scsi piggy backs on the block layer to define the concept
> of a tagged command. But we want to be able to have block-level host-wide
> tags assigned even for untagged commands like the initial INQUIRY, so add
> a new SCSI-level flag for commands that are tagged at the scsi level, so
> that even commands without that set can have tags assigned to them. Note
> that this alredy is the case for the blk-mq code path, and this just lets
> the old path catch up with it.
>
> We also set this flag based upon sdev->simple_tags instead of the block
> queue flag, so that it is entirely independent of the block layer tagging,
> and thus always correct even if a driver doesn't use block level tagging
> yet.
>
> Also remove the old blk_rq_tagged; it was only used by SCSI drivers, and
> removing it forces them to look for the proper replacement.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> Documentation/block/biodoc.txt | 4 ----
> block/blk-core.c | 4 ++--
> drivers/scsi/53c700.c | 6 +++---
> drivers/scsi/aic7xxx/aic7xxx_osm.c | 2 +-
> drivers/scsi/scsi_lib.c | 13 +++++++++----
> drivers/usb/storage/uas.c | 2 +-
> include/linux/blkdev.h | 1 -
> include/scsi/scsi_cmnd.h | 4 ++++
> include/scsi/scsi_tcq.h | 6 ++----
> 9 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
> index 2101e71..6b972b2 100644
> --- a/Documentation/block/biodoc.txt
> +++ b/Documentation/block/biodoc.txt
> @@ -827,10 +827,6 @@ but in the event of any barrier requests in the tag queue we need to ensure
> that requests are restarted in the order they were queue. This may happen
> if the driver needs to use blk_queue_invalidate_tags().
>
> -Tagging also defines a new request flag, REQ_QUEUED. This is set whenever
> -a request is currently tagged. You should not use this flag directly,
> -blk_rq_tagged(rq) is the portable way to do so.
> -
> 3.3 I/O Submission
>
> The routine submit_bio() is used to submit a single io. Higher level i/o
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 0421b53..2e7424b 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1266,7 +1266,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
> blk_clear_rq_complete(rq);
> trace_block_rq_requeue(q, rq);
>
> - if (blk_rq_tagged(rq))
> + if (rq->cmd_flags & REQ_QUEUED)
> blk_queue_end_tag(q, rq);
>
> BUG_ON(blk_queued_rq(rq));
> @@ -2554,7 +2554,7 @@ EXPORT_SYMBOL_GPL(blk_unprep_request);
> */
> void blk_finish_request(struct request *req, int error)
> {
> - if (blk_rq_tagged(req))
> + if (req->cmd_flags & REQ_QUEUED)
> blk_queue_end_tag(req->q, req);
>
> BUG_ON(blk_queued_rq(req));
> diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
> index 474cc6d..5143d32 100644
> --- a/drivers/scsi/53c700.c
> +++ b/drivers/scsi/53c700.c
> @@ -1767,7 +1767,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *)
> */
> if(NCR_700_get_depth(SCp->device) != 0
> && (!(hostdata->tag_negotiated & (1<<scmd_id(SCp)))
> - || !blk_rq_tagged(SCp->request))) {
> + || !(SCp->flags & SCMD_TAGGED))) {
> CDEBUG(KERN_ERR, SCp, "has non zero depth %d\n",
> NCR_700_get_depth(SCp->device));
> return SCSI_MLQUEUE_DEVICE_BUSY;
> @@ -1795,7 +1795,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *)
> printk("53c700: scsi%d, command ", SCp->device->host->host_no);
> scsi_print_command(SCp);
> #endif
> - if(blk_rq_tagged(SCp->request)
> + if ((SCp->flags & SCMD_TAGGED)
> && (hostdata->tag_negotiated &(1<<scmd_id(SCp))) == 0
> && NCR_700_get_tag_neg_state(SCp->device) == NCR_700_START_TAG_NEGOTIATION) {
> scmd_printk(KERN_ERR, SCp, "Enabling Tag Command Queuing\n");
> @@ -1809,7 +1809,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *)
> *
> * FIXME: This will royally screw up on multiple LUN devices
> * */
> - if(!blk_rq_tagged(SCp->request)
> + if (!(SCp->flags & SCMD_TAGGED)
> && (hostdata->tag_negotiated &(1<<scmd_id(SCp)))) {
> scmd_printk(KERN_INFO, SCp, "Disabling Tag Command Queuing\n");
> hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));
> diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
> index d2c9bf3..63bae7c 100644
> --- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
> +++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
> @@ -1447,7 +1447,7 @@ ahc_linux_run_command(struct ahc_softc *ahc, struct ahc_linux_device *dev,
> * we are storing a full busy target *lun*
> * table in SCB space.
> */
> - if (!blk_rq_tagged(cmd->request)
> + if (!(cmd->flags & SCMD_TAGGED)
> && (ahc->features & AHC_SCB_BTT) == 0) {
> int target_offset;
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index fc0a8a0..6b57fae 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1740,7 +1740,7 @@ static void scsi_request_fn(struct request_queue *q)
> * we add the dev to the starved list so it eventually gets
> * a run when a tag is freed.
> */
> - if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
> + if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
> spin_lock_irq(shost->host_lock);
> if (list_empty(&sdev->starved_entry))
> list_add_tail(&sdev->starved_entry,
> @@ -1754,6 +1754,11 @@ static void scsi_request_fn(struct request_queue *q)
>
> if (!scsi_host_queue_ready(q, shost, sdev))
> goto host_not_ready;
> +
> + if (sdev->simple_tags)
> + cmd->flags |= SCMD_TAGGED;
> + else
> + cmd->flags &= ~SCMD_TAGGED;
>
> /*
> * Finally, initialize any error handling parameters, and set up
> @@ -1908,10 +1913,10 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
> blk_mq_start_request(req);
> }
>
> - if (blk_queue_tagged(q))
> - req->cmd_flags |= REQ_QUEUED;
> + if (sdev->simple_tags)
> + cmd->flags |= SCMD_TAGGED;
> else
> - req->cmd_flags &= ~REQ_QUEUED;
> + cmd->flags &= ~SCMD_TAGGED;
>
> scsi_init_cmd_errh(cmd);
> cmd->scsi_done = scsi_mq_done;
> diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
> index 89b2434..b38bc13 100644
> --- a/drivers/usb/storage/uas.c
> +++ b/drivers/usb/storage/uas.c
> @@ -181,7 +181,7 @@ static int uas_get_tag(struct scsi_cmnd *cmnd)
> {
> int tag;
>
> - if (blk_rq_tagged(cmnd->request))
> + if (cmnd->flags & SCMD_TAGGED)
> tag = cmnd->request->tag + 2;
> else
> tag = 1;
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index aac0f9e..6d76b8b 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1136,7 +1136,6 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk)
> /*
> * tag stuff
> */
> -#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
> extern int blk_queue_start_tag(struct request_queue *, struct request *);
> extern struct request *blk_queue_find_tag(struct request_queue *, int);
> extern void blk_queue_end_tag(struct request_queue *, struct request *);
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index 522a5f27..e119142 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -53,6 +53,9 @@ struct scsi_pointer {
> volatile int phase;
> };
>
> +/* for scmd->flags */
> +#define SCMD_TAGGED (1 << 0)
> +
> struct scsi_cmnd {
> struct scsi_device *device;
> struct list_head list; /* scsi_cmnd participates in queue lists */
> @@ -132,6 +135,7 @@ struct scsi_cmnd {
> * to be at an address < 16Mb). */
>
> int result; /* Status code from lower level driver */
> + int flags; /* Command flags */
>
> unsigned char tag; /* SCSI-II queued command tag */
> };
Hmm. Flags with just one value in it ...
bitfield, maybe?
> diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
> index 3090fd0..8f16b94a 100644
> --- a/include/scsi/scsi_tcq.h
> +++ b/include/scsi/scsi_tcq.h
> @@ -101,11 +101,9 @@ static inline void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)
> **/
> static inline int scsi_populate_tag_msg(struct scsi_cmnd *cmd, char *msg)
> {
> - struct request *req = cmd->request;
> -
> - if (blk_rq_tagged(req)) {
> + if (cmd->flags & SCMD_TAGGED) {
> *msg++ = MSG_SIMPLE_TAG;
> - *msg++ = req->tag;
> + *msg++ = cmd->request->tag;
> return 2;
> }
>
>
Other than that:
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 21284 (AG Nürnberg)
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