[RFC 16/16] lpfc: vmid: Introducing vmid in io path.

From: Muneendra <muneendra.kumar@broadcom.com>
To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org
Cc: pbonzini@redhat.com, emilne@redhat.com, mkumar@redhat.com,
	Gaurav Srivastava <gaurav.srivastava@broadcom.com>,
	James Smart <jsmart2021@gmail.com>,
	Muneendra <muneendra.kumar@broadcom.com>
Subject: [RFC 16/16] lpfc: vmid: Introducing vmid in io path.
Date: Tue,  4 Aug 2020 07:43:16 +0530	[thread overview]
Message-ID: <1596507196-27417-17-git-send-email-muneendra.kumar@broadcom.com> (raw)
In-Reply-To: <1596507196-27417-1-git-send-email-muneendra.kumar@broadcom.com>

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

The patch introduces the vmid in the io path. It checks if the vmid is
enabled and if io belongs to a vm or not and acts accordingly. Other
supporing APIs are also included in the patch.

Signed-off-by: Gaurav Srivastava  <gaurav.srivastava@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>
---
 drivers/scsi/lpfc/lpfc_scsi.c | 163 ++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index e5a1056cc575..3c7af8064b12 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -4624,6 +4624,149 @@ void lpfc_vmid_assign_cs_ctl(struct lpfc_vport *vport, struct lpfc_vmid *vmid)
 	}
 }
 
+/*
+ * lpfc_vmid_get_appid- get the vmid associated with the uuid
+ * @vport: The virtual port for which this call is being executed.
+ * @uuid: uuid associated with the VE
+ * @cmd: address of scsi cmmd descriptor
+ * @tag: VMID tag
+ * Returns status of the function
+ */
+static int lpfc_vmid_get_appid(struct lpfc_vport *vport, char *uuid, struct
+			       scsi_cmnd * cmd, union lpfc_vmid_io_tag *tag)
+{
+	struct lpfc_vmid *vmp = NULL;
+	int hash, len, rc = 1, i;
+	u8 pending = 0;
+
+	/* check if QFPA is complete */
+	if (lpfc_vmid_is_type_priority_tag(vport) && !(vport->vmid_flag &
+	      LPFC_VMID_QFPA_CMPL))
+		return 1;
+
+	/* search if the uuid has already been mapped to the vmid */
+	len = strlen(uuid);
+	hash = lpfc_vmid_hash_fn(uuid, len);
+
+	/* search for the VMID in the table */
+	read_lock(&vport->vmid_lock);
+	vmp = lpfc_get_vmid_from_hastable(vport, hash, uuid);
+	read_unlock(&vport->vmid_lock);
+
+	/* if found, check if its already registered  */
+	if (vmp  && vmp->flag & LPFC_VMID_REGISTERED) {
+		lpfc_vmid_update_entry(vport, cmd, vmp, tag);
+		rc = 0;
+	} else if (vmp && (vmp->flag & LPFC_VMID_REQ_REGISTER ||
+			   vmp->flag & LPFC_VMID_DE_REGISTER)) {
+		/* else if register or dereg request has already been sent */
+		/* Hence vmid tag will not be added for this IO */
+		rc = 1;
+	} else {
+		/* else, start the process to obtain one as per the */
+		/* switch connected */
+		write_lock(&vport->vmid_lock);
+		vmp = lpfc_get_vmid_from_hastable(vport, hash, uuid);
+
+		/* while the read lock was released, in case the entry was */
+		/* added by other context or is in process of being added */
+		if (vmp && vmp->flag & LPFC_VMID_REGISTERED) {
+			lpfc_vmid_update_entry(vport, cmd, vmp, tag);
+			write_unlock(&vport->vmid_lock);
+			return 0;
+		} else if (vmp && vmp->flag & LPFC_VMID_REQ_REGISTER) {
+			write_unlock(&vport->vmid_lock);
+			return 1;
+		}
+
+		/* else search and allocate a free slot in the hash table */
+		if (vport->cur_vmid_cnt < vport->max_vmid) {
+			for (i = 0; i < vport->max_vmid; ++i) {
+				vmp = vport->vmid + i;
+				if (vmp->flag == LPFC_VMID_SLOT_FREE) {
+					vmp = vport->vmid + i;
+					break;
+				}
+			}
+		} else {
+			write_unlock(&vport->vmid_lock);
+			return 1;
+		}
+
+		if (vmp && (vmp->flag == LPFC_VMID_SLOT_FREE)) {
+			vmp->vmid_len = len;
+
+			/* Add the vmid and register  */
+			memcpy(vmp->host_vmid, uuid, vmp->vmid_len);
+			vmp->io_rd_cnt = 0;
+			vmp->io_wr_cnt = 0;
+			vmp->flag = LPFC_VMID_SLOT_USED;
+			lpfc_put_vmid_in_hashtable(vport, hash, vmp);
+
+			vmp->delete_inactive =
+			    vport->vmid_inactivity_timeout ? 1 : 0;
+
+			/* if type priority tag, get next available vmid */
+			if (lpfc_vmid_is_type_priority_tag(vport))
+				lpfc_vmid_assign_cs_ctl(vport, vmp);
+
+			/* allocate the per cpu variable for holding */
+			/* the last access time stamp only if vmid is enabled */
+			if (!vmp->last_io_time)
+				vmp->last_io_time =
+				    __alloc_percpu(sizeof(u64),
+						   __alignof__(struct
+							       lpfc_vmid));
+
+			/* registration pending */
+			pending = 1;
+			rc = 1;
+		}
+		write_unlock(&vport->vmid_lock);
+
+		/* complete transaction with switch */
+		if (pending) {
+			if (lpfc_vmid_is_type_priority_tag(vport))
+				rc = lpfc_vmid_uvem(vport, vmp, true);
+			else
+				rc = lpfc_vmid_cmd(vport,
+						   SLI_CTAS_RAPP_IDENT,
+						   vmp);
+			if (!rc) {
+				write_lock(&vport->vmid_lock);
+				vport->cur_vmid_cnt++;
+				vmp->flag |= LPFC_VMID_REQ_REGISTER;
+				write_unlock(&vport->vmid_lock);
+			}
+		}
+
+		/* finally, enable the idle timer once */
+		if (!(vport->phba->pport->vmid_flag & LPFC_VMID_TIMER_ENBLD)) {
+			mod_timer(&vport->phba->inactive_vmid_poll,
+				  jiffies +
+				  msecs_to_jiffies(1000 * LPFC_VMID_TIMER));
+			vport->phba->pport->vmid_flag |= LPFC_VMID_TIMER_ENBLD;
+		}
+	}
+	return rc;
+}
+
+/*
+ * lpfc_is_command_vm_io - get the uuid from blk cgroup
+ * @cmd:Pointer to scsi_cmnd data structure
+ * Returns uuid if present if not null
+ */
+static char *lpfc_is_command_vm_io(struct scsi_cmnd *cmd)
+{
+	char *uuid = NULL;
+
+	if (cmd->request) {
+		if (cmd->request->bio)
+			uuid = blkcg_get_app_identifier(cmd->request->bio);
+	}
+	return uuid;
+}
+
 /**
  * lpfc_queuecommand - scsi_host_template queuecommand entry point
  * @cmnd: Pointer to scsi_cmnd data structure.
@@ -4649,6 +4792,7 @@ lpfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 	int err, idx;
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
 	uint64_t start = 0L;
+	u8 *uuid = NULL;
 
 	if (phba->ktime_on)
 		start = ktime_get_ns();
@@ -4772,6 +4916,25 @@ lpfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 
 	lpfc_scsi_prep_cmnd(vport, lpfc_cmd, ndlp);
 
+	/* check the necessary and sufficient condition to support VMID */
+	if (lpfc_is_vmid_enabled(phba) &&
+	    (ndlp->vmid_support ||
+	     phba->pport->vmid_priority_tagging ==
+	     LPFC_VMID_PRIO_TAG_ALL_TARGETS)) {
+		/* is the IO generated by a VM, get the associated virtual */
+		/* entity id */
+		uuid = lpfc_is_command_vm_io(cmnd);
+
+		if (uuid) {
+			err = lpfc_vmid_get_appid(vport, uuid, cmnd,
+				(union lpfc_vmid_io_tag *)
+					&lpfc_cmd->cur_iocbq.vmid_tag);
+			if (!err)
+				lpfc_cmd->cur_iocbq.iocb_flag |= LPFC_IO_VMID;
+		}
+	}
+
+	atomic_inc(&ndlp->cmd_pending);
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
 	if (unlikely(phba->hdwqstat_on & LPFC_CHECK_SCSI_IO))
 		this_cpu_inc(phba->sli4_hba.c_stat->xmt_io);
-- 
2.18.2

