[PATCH v9 11/13] lpfc: vmid: Timeout implementation for vmid

From: Muneendra <muneendra.kumar@broadcom.com>
To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
	tj@kernel.org, linux-nvme@lists.infradead.org, hare@suse.de
Cc: jsmart2021@gmail.com, emilne@redhat.com, mkumar@redhat.com,
	Gaurav Srivastava <gaurav.srivastava@broadcom.com>
Subject: [PATCH v9 11/13] lpfc: vmid: Timeout implementation for vmid
Date: Wed,  7 Apr 2021 04:36:35 +0530	[thread overview]
Message-ID: <1617750397-26466-12-git-send-email-muneendra.kumar@broadcom.com> (raw)
In-Reply-To: <1617750397-26466-1-git-send-email-muneendra.kumar@broadcom.com>

From: Gaurav Srivastava <gaurav.srivastava@broadcom.com>

This patch implements the timeout functionality for the vmid. After the
set time period of inactivity, the vmid is deregistered from the switch.

Signed-off-by: Gaurav Srivastava  <gaurav.srivastava@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>

---
v9:
Modified code for use of hashtable

v8:
Fixed the uninitialized variable

v7:
No change

v6:
Added Forward declarations

v5:
No change

v4:
No change

v3:
No change

v2:
Ported the patch on top of 5.10/scsi-queue
---
 drivers/scsi/lpfc/lpfc_hbadisc.c | 104 +++++++++++++++++++++++++++++++
 drivers/scsi/lpfc/lpfc_init.c    |  40 ++++++++++++
 2 files changed, 144 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index 3b5cd23dd172..4cf1bc418bea 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -72,6 +72,7 @@ static void lpfc_disc_flush_list(struct lpfc_vport *vport);
 static void lpfc_unregister_fcfi_cmpl(struct lpfc_hba *, LPFC_MBOXQ_t *);
 static int lpfc_fcf_inuse(struct lpfc_hba *);
 static void lpfc_mbx_cmpl_read_sparam(struct lpfc_hba *, LPFC_MBOXQ_t *);
+static void lpfc_check_inactive_vmid(struct lpfc_hba *phba);
 
 static int
 lpfc_valid_xpt_node(struct lpfc_nodelist *ndlp)
@@ -239,6 +240,109 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 	return;
 }
 
+/**
+ * lpfc_check_inactive_vmid_one - VMID inactivity checker for a vport
+ * @vport: Pointer to vport context object.
+ *
+ * This function checks for idle vmid entries related to a particular vport. If
+ * found unused/idle, it frees them accordingly.
+ **/
+static void lpfc_check_inactive_vmid_one(struct lpfc_vport *vport)
+{
+	u16 keep;
+	u32 difftime = 0, r, bucket;
+	u64 *lta;
+	int cpu;
+	struct lpfc_vmid *vmp;
+
+	write_lock(&vport->vmid_lock);
+
+	if (!vport->cur_vmid_cnt)
+		goto out;
+
+	/* iterate through the table */
+	hash_for_each(vport->hash_table, bucket, vmp, hnode) {
+		keep = 0;
+		if (vmp->flag & LPFC_VMID_REGISTERED) {
+			/* check if the particular vmid is in use */
+			/* for all available per cpu variable */
+			for_each_possible_cpu(cpu) {
+				/* if last access time is less than timeout */
+				lta = per_cpu_ptr(vmp->last_io_time, cpu);
+				if (!lta)
+					continue;
+				difftime = (jiffies) - (*lta);
+				if ((vport->vmid_inactivity_timeout *
+				     JIFFIES_PER_HR) > difftime) {
+					keep = 1;
+					break;
+				}
+			}
+
+			/* if none of the cpus have been used by the vm, */
+			/*  remove the entry if already registered */
+			if (!keep) {
+				/* mark the entry for deregistration */
+				vmp->flag = LPFC_VMID_DE_REGISTER;
+				write_unlock(&vport->vmid_lock);
+				if (vport->vmid_priority_tagging)
+					r = lpfc_vmid_uvem(vport, vmp, false);
+				else
+					r = lpfc_vmid_cmd(vport,
+							  SLI_CTAS_DAPP_IDENT,
+							  vmp);
+
+				/* decrement number of active vms and mark */
+				/* entry in slot as free */
+				write_lock(&vport->vmid_lock);
+				if (!r) {
+					struct lpfc_vmid *ht = vmp;
+					vport->cur_vmid_cnt--;
+					ht->flag = LPFC_VMID_SLOT_FREE;
+					free_percpu(ht->last_io_time);
+					ht->last_io_time = NULL;
+					hash_del(&ht->hnode);
+				}
+			}
+		}
+	}
+ out:
+	write_unlock(&vport->vmid_lock);
+}
+
+/**
+ * lpfc_check_inactive_vmid - VMID inactivity checker
+ * @phba: Pointer to hba context object.
+ *
+ * This function is called from the worker thread to determine if an entry in
+ * the vmid table can be released since there was no IO activity seen from that
+ * particular VM for the specified time. When this happens, the entry in the
+ * table is released and also the resources on the switch cleared.
+ **/
+
+static void lpfc_check_inactive_vmid(struct lpfc_hba *phba)
+{
+	struct lpfc_vport *vport;
+	struct lpfc_vport **vports;
+	int i;
+
+	vports = lpfc_create_vport_work_array(phba);
+	if (!vports)
+		return;
+
+	for (i = 0; i <= phba->max_vports; i++) {
+		if ((!vports[i]) && (i == 0))
+			vport = phba->pport;
+		else
+			vport = vports[i];
+		if (!vport)
+			break;
+
+		lpfc_check_inactive_vmid_one(vport);
+	}
+	lpfc_destroy_vport_work_array(phba, vports);
+}
+
 /**
  * lpfc_dev_loss_tmo_handler - Remote node devloss timeout handler
  * @ndlp: Pointer to remote node object.
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index a506ab453343..e59d28b9704c 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -4856,6 +4856,42 @@ lpfc_sli4_fcf_redisc_wait_tmo(struct timer_list *t)
 	lpfc_worker_wake_up(phba);
 }
 
+/**
+ * lpfc_vmid_poll - VMID timeout detection
+ * @ptr: Map to lpfc_hba data structure pointer.
+ *
+ * This routine is invoked when there is no IO on by a VM for the specified
+ * amount of time. When this situation is detected, the VMID has to be
+ * deregistered from the switch and all the local resources freed. The VMID
+ * will be reassigned to the VM once the IO begins.
+ **/
+static void
+lpfc_vmid_poll(struct timer_list *t)
+{
+	struct lpfc_hba *phba = from_timer(phba, t, inactive_vmid_poll);
+	u32 wake_up = 0;
+
+	/* check if there is a need to issue QFPA */
+	if (phba->pport->vmid_priority_tagging) {
+		wake_up = 1;
+		phba->pport->work_port_events |= WORKER_CHECK_VMID_ISSUE_QFPA;
+	}
+
+	/* Is the vmid inactivity timer enabled */
+	if (phba->pport->vmid_inactivity_timeout ||
+	    phba->pport->load_flag & FC_DEREGISTER_ALL_APP_ID) {
+		wake_up = 1;
+		phba->pport->work_port_events |= WORKER_CHECK_INACTIVE_VMID;
+	}
+
+	if (wake_up)
+		lpfc_worker_wake_up(phba);
+
+	/* restart the timer for the next iteration */
+	mod_timer(&phba->inactive_vmid_poll, jiffies + msecs_to_jiffies(1000 *
+							LPFC_VMID_TIMER));
+}
+
 /**
  * lpfc_sli4_parse_latt_fault - Parse sli4 link-attention link fault code
  * @phba: pointer to lpfc hba data structure.
@@ -6706,6 +6742,10 @@ lpfc_sli4_driver_resource_setup(struct lpfc_hba *phba)
 	phba->hbqs[LPFC_ELS_HBQ].hbq_alloc_buffer = lpfc_sli4_rb_alloc;
 	phba->hbqs[LPFC_ELS_HBQ].hbq_free_buffer = lpfc_sli4_rb_free;
 
+	/* for VMID idle timeout if VMID is enabled */
+	if (lpfc_is_vmid_enabled(phba))
+		timer_setup(&phba->inactive_vmid_poll, lpfc_vmid_poll, 0);
+
 	/*
 	 * Initialize the SLI Layer to run with lpfc SLI4 HBAs.
 	 */
-- 
2.26.2

