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From:   Karan Tilak Kumar <kartilak@cisco.com>
To:     sebaddel@cisco.com
Cc:     arulponn@cisco.com, djhawar@cisco.com, gcboffa@cisco.com,
        mkai2@cisco.com, satishkh@cisco.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Karan Tilak Kumar <kartilak@cisco.com>
Subject: [PATCH v6 09/13] scsi: fnic: Remove usage of host_lock
Date:   Mon, 11 Dec 2023 09:36:13 -0800
Message-Id: <20231211173617.932990-10-kartilak@cisco.com>
In-Reply-To: <20231211173617.932990-1-kartilak@cisco.com>
References: <20231211173617.932990-1-kartilak@cisco.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Remove usage of host_lock.
Replace with fnic_lock, where necessary.
fnic does not use host_lock. fnic uses fnic_lock.
Use fnic lock to protect fnic members in fnic_queuecommand.
Add log messages in error cases.

Reviewed-by: Sesidhar Baddela <sebaddel@cisco.com>
Reviewed-by: Arulprabhu Ponnusamy <arulponn@cisco.com>
Signed-off-by: Karan Tilak Kumar <kartilak@cisco.com>
---
Changes between v4 and v5:
    Incorporate review comments from Martin:
	Modify patch commits to include a "---" separator.

Changes between v2 and v3:
    Squash the following commits into one:
    scsi: fnic: Remove usage of host_lock
    scsi: fnic: Use fnic_lock to protect fnic structures
    in queuecommand
---
 drivers/scsi/fnic/fnic_scsi.c | 55 ++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index c7f3bfc650d1..e9acb2e7dd2e 100644
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -170,17 +170,14 @@ __fnic_set_state_flags(struct fnic *fnic, unsigned long st_flags,
 			unsigned long clearbits)
 {
 	unsigned long flags = 0;
-	unsigned long host_lock_flags = 0;
 
 	spin_lock_irqsave(&fnic->fnic_lock, flags);
-	spin_lock_irqsave(fnic->lport->host->host_lock, host_lock_flags);
 
 	if (clearbits)
 		fnic->state_flags &= ~st_flags;
 	else
 		fnic->state_flags |= st_flags;
 
-	spin_unlock_irqrestore(fnic->lport->host->host_lock, host_lock_flags);
 	spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 
 	return;
@@ -427,14 +424,27 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 	int io_lock_acquired = 0;
 	struct fc_rport_libfc_priv *rp;
 
-	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_IO_BLOCKED)))
+	spin_lock_irqsave(&fnic->fnic_lock, flags);
+
+	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_IO_BLOCKED))) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		FNIC_SCSI_DBG(KERN_ERR, fnic->lport->host,
+			"fnic<%d>: %s: %d: fnic IO blocked flags: 0x%lx. Returning SCSI_MLQUEUE_HOST_BUSY\n",
+			fnic->fnic_num, __func__, __LINE__, fnic->state_flags);
 		return SCSI_MLQUEUE_HOST_BUSY;
+	}
 
-	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_FWRESET)))
+	if (unlikely(fnic_chk_state_flags_locked(fnic, FNIC_FLAGS_FWRESET))) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		FNIC_SCSI_DBG(KERN_ERR, fnic->lport->host,
+			"fnic<%d>: %s: %d: fnic flags: 0x%lx. Returning SCSI_MLQUEUE_HOST_BUSY\n",
+			fnic->fnic_num, __func__, __LINE__, fnic->state_flags);
 		return SCSI_MLQUEUE_HOST_BUSY;
+	}
 
 	rport = starget_to_rport(scsi_target(sc->device));
 	if (!rport) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 				"returning DID_NO_CONNECT for IO as rport is NULL\n");
 		sc->result = DID_NO_CONNECT << 16;
@@ -444,6 +454,7 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 
 	ret = fc_remote_port_chkready(rport);
 	if (ret) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 				"rport is not ready\n");
 		atomic64_inc(&fnic_stats->misc_stats.rport_not_ready);
@@ -454,6 +465,7 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 
 	rp = rport->dd_data;
 	if (!rp || rp->rp_state == RPORT_ST_DELETE) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 			"rport 0x%x removed, returning DID_NO_CONNECT\n",
 			rport->port_id);
@@ -465,6 +477,7 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 	}
 
 	if (rp->rp_state != RPORT_ST_READY) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 		FNIC_SCSI_DBG(KERN_DEBUG, fnic->lport->host,
 			"rport 0x%x in state 0x%x, returning DID_IMM_RETRY\n",
 			rport->port_id, rp->rp_state);
@@ -474,17 +487,17 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 		return 0;
 	}
 
-	if (lp->state != LPORT_ST_READY || !(lp->link_up))
+	if (lp->state != LPORT_ST_READY || !(lp->link_up)) {
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
+		FNIC_SCSI_DBG(KERN_ERR, fnic->lport->host,
+			"fnic<%d>: %s: %d: state not ready: %d/link not up: %d Returning HOST_BUSY\n",
+			fnic->fnic_num, __func__, __LINE__, lp->state, lp->link_up);
 		return SCSI_MLQUEUE_HOST_BUSY;
+	}
 
 	atomic_inc(&fnic->in_flight);
 
-	/*
-	 * Release host lock, use driver resource specific locks from here.
-	 * Don't re-enable interrupts in case they were disabled prior to the
-	 * caller disabling them.
-	 */
-	spin_unlock(lp->host->host_lock);
+	spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 	fnic_priv(sc)->state = FNIC_IOREQ_NOT_INITED;
 	fnic_priv(sc)->flags = FNIC_NO_FLAGS;
 
@@ -569,8 +582,6 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 			mempool_free(io_req, fnic->io_req_pool);
 		}
 		atomic_dec(&fnic->in_flight);
-		/* acquire host lock before returning to SCSI */
-		spin_lock(lp->host->host_lock);
 		return ret;
 	} else {
 		atomic64_inc(&fnic_stats->io_stats.active_ios);
@@ -598,8 +609,6 @@ static int fnic_queuecommand_lck(struct scsi_cmnd *sc)
 		spin_unlock_irqrestore(io_lock, flags);
 
 	atomic_dec(&fnic->in_flight);
-	/* acquire host lock before returning to SCSI */
-	spin_lock(lp->host->host_lock);
 	return ret;
 }
 
@@ -1493,18 +1502,17 @@ static inline int fnic_queue_abort_io_req(struct fnic *fnic, int tag,
 					  struct fnic_io_req *io_req)
 {
 	struct vnic_wq_copy *wq = &fnic->hw_copy_wq[0];
-	struct Scsi_Host *host = fnic->lport->host;
 	struct misc_stats *misc_stats = &fnic->fnic_stats.misc_stats;
 	unsigned long flags;
 
-	spin_lock_irqsave(host->host_lock, flags);
+	spin_lock_irqsave(&fnic->fnic_lock, flags);
 	if (unlikely(fnic_chk_state_flags_locked(fnic,
 						FNIC_FLAGS_IO_BLOCKED))) {
-		spin_unlock_irqrestore(host->host_lock, flags);
+		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 		return 1;
 	} else
 		atomic_inc(&fnic->in_flight);
-	spin_unlock_irqrestore(host->host_lock, flags);
+	spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 
 	spin_lock_irqsave(&fnic->wq_copy_lock[0], flags);
 
@@ -1939,7 +1947,6 @@ static inline int fnic_queue_dr_io_req(struct fnic *fnic,
 				       struct fnic_io_req *io_req)
 {
 	struct vnic_wq_copy *wq = &fnic->hw_copy_wq[0];
-	struct Scsi_Host *host = fnic->lport->host;
 	struct misc_stats *misc_stats = &fnic->fnic_stats.misc_stats;
 	struct scsi_lun fc_lun;
 	int ret = 0;
@@ -1949,14 +1956,14 @@ static inline int fnic_queue_dr_io_req(struct fnic *fnic,
 	if (tag == SCSI_NO_TAG)
 		tag = io_req->tag;
 
-	spin_lock_irqsave(host->host_lock, intr_flags);
+	spin_lock_irqsave(&fnic->fnic_lock, intr_flags);
 	if (unlikely(fnic_chk_state_flags_locked(fnic,
 						FNIC_FLAGS_IO_BLOCKED))) {
-		spin_unlock_irqrestore(host->host_lock, intr_flags);
+		spin_unlock_irqrestore(&fnic->fnic_lock, intr_flags);
 		return FAILED;
 	} else
 		atomic_inc(&fnic->in_flight);
-	spin_unlock_irqrestore(host->host_lock, intr_flags);
+	spin_unlock_irqrestore(&fnic->fnic_lock, intr_flags);
 
 	spin_lock_irqsave(&fnic->wq_copy_lock[0], intr_flags);
 
-- 
2.31.1