[PATCH RFC v3 07/41] fnic: use reserved commands

[Hannes Reinecke <hare@suse.de>]

From: Hannes Reinecke <hare@suse.com>

Remove hack to get tag for the reset command by using reserved
commands.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/fnic/fnic_scsi.c | 147 ++++++++++++++----------------------------
 1 file changed, 49 insertions(+), 98 deletions(-)

diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index b60795893994..228729013e21 100644
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -101,7 +101,7 @@ static const char *fnic_fcpio_status_to_str(unsigned int status)
 	return fcpio_status_str[status];
 }
 
-static void fnic_cleanup_io(struct fnic *fnic, int exclude_id);
+static void fnic_cleanup_io(struct fnic *fnic);
 
 static inline spinlock_t *fnic_io_lock_hash(struct fnic *fnic,
 					    struct scsi_cmnd *sc)
@@ -637,7 +637,7 @@ static int fnic_fcpio_fw_reset_cmpl_handler(struct fnic *fnic,
 	atomic64_inc(&reset_stats->fw_reset_completions);
 
 	/* Clean up all outstanding io requests */
-	fnic_cleanup_io(fnic, SCSI_NO_TAG);
+	fnic_cleanup_io(fnic);
 
 	atomic64_set(&fnic->fnic_stats.fw_stats.active_fw_reqs, 0);
 	atomic64_set(&fnic->fnic_stats.io_stats.active_ios, 0);
@@ -1359,7 +1359,7 @@ int fnic_wq_copy_cmpl_handler(struct fnic *fnic, int copy_work_to_do)
 	return wq_work_done;
 }
 
-static void fnic_cleanup_io(struct fnic *fnic, int exclude_id)
+static void fnic_cleanup_io(struct fnic *fnic)
 {
 	int i;
 	struct fnic_io_req *io_req;
@@ -1370,9 +1370,6 @@ static void fnic_cleanup_io(struct fnic *fnic, int exclude_id)
 	struct fnic_stats *fnic_stats = &fnic->fnic_stats;
 
 	for (i = 0; i < fnic->fnic_max_tag_id; i++) {
-		if (i == exclude_id)
-			continue;
-
 		io_lock = fnic_io_lock_tag(fnic, i);
 		spin_lock_irqsave(io_lock, flags);
 		sc = scsi_host_find_tag(fnic->lport->host, i);
@@ -2125,9 +2122,7 @@ static inline int fnic_queue_dr_io_req(struct fnic *fnic,
  * successfully aborted, 1 otherwise
  */
 static int fnic_clean_pending_aborts(struct fnic *fnic,
-				     struct scsi_cmnd *lr_sc,
-					 bool new_sc)
-
+				     struct scsi_cmnd *lr_sc)
 {
 	int tag, abt_tag;
 	struct fnic_io_req *io_req;
@@ -2148,7 +2143,7 @@ static int fnic_clean_pending_aborts(struct fnic *fnic,
 		 * ignore this lun reset cmd if issued using new SC
 		 * or cmds that do not belong to this lun
 		 */
-		if (!sc || ((sc == lr_sc) && new_sc) || sc->device != lun_dev) {
+		if (!sc || sc == lr_sc || sc->device != lun_dev) {
 			spin_unlock_irqrestore(io_lock, flags);
 			continue;
 		}
@@ -2287,38 +2282,6 @@ static int fnic_clean_pending_aborts(struct fnic *fnic,
 	return ret;
 }
 
-/**
- * fnic_scsi_host_start_tag
- * Allocates tagid from host's tag list
- **/
-static inline int
-fnic_scsi_host_start_tag(struct fnic *fnic, struct scsi_cmnd *sc)
-{
-	struct request_queue *q = sc->request->q;
-	struct request *dummy;
-
-	dummy = blk_mq_alloc_request(q, REQ_OP_WRITE, BLK_MQ_REQ_NOWAIT);
-	if (IS_ERR(dummy))
-		return SCSI_NO_TAG;
-
-	sc->tag = sc->request->tag = dummy->tag;
-	sc->host_scribble = (unsigned char *)dummy;
-
-	return dummy->tag;
-}
-
-/**
- * fnic_scsi_host_end_tag
- * frees tag allocated by fnic_scsi_host_start_tag.
- **/
-static inline void
-fnic_scsi_host_end_tag(struct fnic *fnic, struct scsi_cmnd *sc)
-{
-	struct request *dummy = (struct request *)sc->host_scribble;
-
-	blk_mq_free_request(dummy);
-}
-
 /*
  * SCSI Eh thread issues a Lun Reset when one or more commands on a LUN
  * fail to get aborted. It calls driver's eh_device_reset with a SCSI command
@@ -2335,19 +2298,19 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 	spinlock_t *io_lock;
 	unsigned long flags;
 	unsigned long start_time = 0;
+	struct scsi_device *sdev = sc->device;
 	struct scsi_lun fc_lun;
 	struct fnic_stats *fnic_stats;
 	struct reset_stats *reset_stats;
 	int tag = 0;
 	DECLARE_COMPLETION_ONSTACK(tm_done);
-	int tag_gen_flag = 0;   /*to track tags allocated by fnic driver*/
-	bool new_sc = 0;
+	struct scsi_cmnd *reset_sc = NULL;
 
 	/* Wait for rport to unblock */
 	fc_block_scsi_eh(sc);
 
 	/* Get local-port, check ready and link up */
-	lp = shost_priv(sc->device->host);
+	lp = shost_priv(sdev->host);
 
 	fnic = lport_priv(lp);
 	fnic_stats = &fnic->fnic_stats;
@@ -2355,10 +2318,10 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 
 	atomic64_inc(&reset_stats->device_resets);
 
-	rport = starget_to_rport(scsi_target(sc->device));
+	rport = starget_to_rport(scsi_target(sdev));
 	FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 		      "Device reset called FCID 0x%x, LUN 0x%llx sc 0x%p\n",
-		      rport->port_id, sc->device->lun, sc);
+		      rport->port_id, sdev->lun, sc);
 
 	if (lp->state != LPORT_ST_READY || !(lp->link_up))
 		goto fnic_device_reset_end;
@@ -2369,42 +2332,31 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 		goto fnic_device_reset_end;
 	}
 
-	CMD_FLAGS(sc) = FNIC_DEVICE_RESET;
-	/* Allocate tag if not present */
+	reset_sc = scsi_get_reserved_cmd(sdev, DMA_NONE);
+	if (unlikely(!reset_sc))
+		goto fnic_device_reset_end;
 
-	tag = sc->request->tag;
-	if (unlikely(tag < 0)) {
-		/*
-		 * Really should fix the midlayer to pass in a proper
-		 * request for ioctls...
-		 */
-		tag = fnic_scsi_host_start_tag(fnic, sc);
-		if (unlikely(tag == SCSI_NO_TAG))
-			goto fnic_device_reset_end;
-		tag_gen_flag = 1;
-		new_sc = 1;
-	}
-	io_lock = fnic_io_lock_hash(fnic, sc);
+	CMD_FLAGS(reset_sc) = FNIC_DEVICE_RESET;
+	tag = reset_sc->request->tag;
+	io_lock = fnic_io_lock_hash(fnic, reset_sc);
 	spin_lock_irqsave(io_lock, flags);
-	io_req = (struct fnic_io_req *)CMD_SP(sc);
+	io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 
 	/*
-	 * If there is a io_req attached to this command, then use it,
-	 * else allocate a new one.
+	 * Allocate a new io_req.
 	 */
+	io_req = mempool_alloc(fnic->io_req_pool, GFP_ATOMIC);
 	if (!io_req) {
-		io_req = mempool_alloc(fnic->io_req_pool, GFP_ATOMIC);
-		if (!io_req) {
-			spin_unlock_irqrestore(io_lock, flags);
-			goto fnic_device_reset_end;
-		}
-		memset(io_req, 0, sizeof(*io_req));
-		io_req->port_id = rport->port_id;
-		CMD_SP(sc) = (char *)io_req;
+		spin_unlock_irqrestore(io_lock, flags);
+		goto fnic_device_reset_end;
 	}
+	memset(io_req, 0, sizeof(*io_req));
+	io_req->port_id = rport->port_id;
+	CMD_SP(reset_sc) = (char *)io_req;
+
 	io_req->dr_done = &tm_done;
-	CMD_STATE(sc) = FNIC_IOREQ_CMD_PENDING;
-	CMD_LR_STATUS(sc) = FCPIO_INVALID_CODE;
+	CMD_STATE(reset_sc) = FNIC_IOREQ_CMD_PENDING;
+	CMD_LR_STATUS(reset_sc) = FCPIO_INVALID_CODE;
 	spin_unlock_irqrestore(io_lock, flags);
 
 	FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host, "TAG %x\n", tag);
@@ -2413,15 +2365,15 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 	 * issue the device reset, if enqueue failed, clean up the ioreq
 	 * and break assoc with scsi cmd
 	 */
-	if (fnic_queue_dr_io_req(fnic, sc, io_req)) {
+	if (fnic_queue_dr_io_req(fnic, reset_sc, io_req)) {
 		spin_lock_irqsave(io_lock, flags);
-		io_req = (struct fnic_io_req *)CMD_SP(sc);
+		io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 		if (io_req)
 			io_req->dr_done = NULL;
 		goto fnic_device_reset_clean;
 	}
 	spin_lock_irqsave(io_lock, flags);
-	CMD_FLAGS(sc) |= FNIC_DEV_RST_ISSUED;
+	CMD_FLAGS(reset_sc) |= FNIC_DEV_RST_ISSUED;
 	spin_unlock_irqrestore(io_lock, flags);
 
 	/*
@@ -2432,16 +2384,16 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 				    msecs_to_jiffies(FNIC_LUN_RESET_TIMEOUT));
 
 	spin_lock_irqsave(io_lock, flags);
-	io_req = (struct fnic_io_req *)CMD_SP(sc);
+	io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 	if (!io_req) {
 		spin_unlock_irqrestore(io_lock, flags);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
-				"io_req is null tag 0x%x sc 0x%p\n", tag, sc);
+				"io_req is null tag 0x%x sc 0x%p\n", tag, reset_sc);
 		goto fnic_device_reset_end;
 	}
 	io_req->dr_done = NULL;
 
-	status = CMD_LR_STATUS(sc);
+	status = CMD_LR_STATUS(reset_sc);
 
 	/*
 	 * If lun reset not completed, bail out with failed. io_req
@@ -2451,16 +2403,16 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 		atomic64_inc(&reset_stats->device_reset_timeouts);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 			      "Device reset timed out\n");
-		CMD_FLAGS(sc) |= FNIC_DEV_RST_TIMED_OUT;
+		CMD_FLAGS(reset_sc) |= FNIC_DEV_RST_TIMED_OUT;
 		spin_unlock_irqrestore(io_lock, flags);
-		int_to_scsilun(sc->device->lun, &fc_lun);
+		int_to_scsilun(sdev->lun, &fc_lun);
 		/*
 		 * Issue abort and terminate on device reset request.
 		 * If q'ing of terminate fails, retry it after a delay.
 		 */
 		while (1) {
 			spin_lock_irqsave(io_lock, flags);
-			if (CMD_FLAGS(sc) & FNIC_DEV_RST_TERM_ISSUED) {
+			if (CMD_FLAGS(reset_sc) & FNIC_DEV_RST_TERM_ISSUED) {
 				spin_unlock_irqrestore(io_lock, flags);
 				break;
 			}
@@ -2473,13 +2425,13 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 				msecs_to_jiffies(FNIC_ABT_TERM_DELAY_TIMEOUT));
 			} else {
 				spin_lock_irqsave(io_lock, flags);
-				CMD_FLAGS(sc) |= FNIC_DEV_RST_TERM_ISSUED;
-				CMD_STATE(sc) = FNIC_IOREQ_ABTS_PENDING;
+				CMD_FLAGS(reset_sc) |= FNIC_DEV_RST_TERM_ISSUED;
+				CMD_STATE(reset_sc) = FNIC_IOREQ_ABTS_PENDING;
 				io_req->abts_done = &tm_done;
 				spin_unlock_irqrestore(io_lock, flags);
 				FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 				"Abort and terminate issued on Device reset "
-				"tag 0x%x sc 0x%p\n", tag, sc);
+				"tag 0x%x sc 0x%p\n", tag, reset_sc);
 				break;
 			}
 		}
@@ -2491,7 +2443,7 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 				msecs_to_jiffies(FNIC_LUN_RESET_TIMEOUT));
 				break;
 			} else {
-				io_req = (struct fnic_io_req *)CMD_SP(sc);
+				io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 				io_req->abts_done = NULL;
 				goto fnic_device_reset_clean;
 			}
@@ -2506,7 +2458,7 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 		FNIC_SCSI_DBG(KERN_DEBUG,
 			      fnic->lport->host,
 			      "Device reset completed - failed\n");
-		io_req = (struct fnic_io_req *)CMD_SP(sc);
+		io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 		goto fnic_device_reset_clean;
 	}
 
@@ -2517,7 +2469,7 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 	 * the lun reset cmd. If all cmds get cleaned, the lun reset
 	 * succeeds
 	 */
-	if (fnic_clean_pending_aborts(fnic, sc, new_sc)) {
+	if (fnic_clean_pending_aborts(fnic, reset_sc)) {
 		spin_lock_irqsave(io_lock, flags);
 		io_req = (struct fnic_io_req *)CMD_SP(sc);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
@@ -2528,35 +2480,34 @@ int fnic_device_reset(struct scsi_cmnd *sc)
 
 	/* Clean lun reset command */
 	spin_lock_irqsave(io_lock, flags);
-	io_req = (struct fnic_io_req *)CMD_SP(sc);
+	io_req = (struct fnic_io_req *)CMD_SP(reset_sc);
 	if (io_req)
 		/* Completed, and successful */
 		ret = SUCCESS;
 
 fnic_device_reset_clean:
 	if (io_req)
-		CMD_SP(sc) = NULL;
+		CMD_SP(reset_sc) = NULL;
 
 	spin_unlock_irqrestore(io_lock, flags);
 
 	if (io_req) {
 		start_time = io_req->start_time;
-		fnic_release_ioreq_buf(fnic, io_req, sc);
+		fnic_release_ioreq_buf(fnic, io_req, reset_sc);
 		mempool_free(io_req, fnic->io_req_pool);
 	}
 
 fnic_device_reset_end:
-	FNIC_TRACE(fnic_device_reset, sc->device->host->host_no,
-		  sc->request->tag, sc,
+	FNIC_TRACE(fnic_device_reset, sdev->host->host_no,
+		   reset_sc->request->tag, reset_sc,
 		  jiffies_to_msecs(jiffies - start_time),
-		  0, ((u64)sc->cmnd[0] << 32 |
+		  0, ((u64)reset_sc->cmnd[0] << 32 |
 		  (u64)sc->cmnd[2] << 24 | (u64)sc->cmnd[3] << 16 |
 		  (u64)sc->cmnd[4] << 8 | sc->cmnd[5]),
 		  (((u64)CMD_FLAGS(sc) << 32) | CMD_STATE(sc)));
 
 	/* free tag if it is allocated */
-	if (unlikely(tag_gen_flag))
-		fnic_scsi_host_end_tag(fnic, sc);
+	scsi_put_reserved_cmd(reset_sc);
 
 	FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 		      "Returning from device reset %s\n",
-- 
2.16.4