[PATCH v10 13/13] lpfc: vmid: Introducing vmid in io path.

Muneendra
2021-04-28T05:35:38Z

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.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Gaurav Srivastava <gaurav.srivastava@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>

---
v10:
Remove redundant code and function name correction

v9:
Added changes related to locking and new hashtable implementation

v8:
Added proper error codes
updated logic while handling vmid

v7:
No change

v6:
No change

v5:
No change

v4:
No change

v3:
Replaced blkcg_get_app_identifier with blkcg_get_fc_appid

v2:
Ported the patch on top of 5.10/scsi-queue
Added a fix for issuing QFPA command which was not included in the
last submit
---
drivers/scsi/lpfc/lpfc_scsi.c | 174 ++++++++++++++++++++++++++++++++++
1 file changed, 174 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 0b35cab90627..1bc6ecf3ec61 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -5263,6 +5263,160 @@ static void lpfc_vmid_assign_cs_ctl(struct lpfc_vport *vport,
}
}

+/*
+ * 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, i;
+
+ /* check if QFPA is complete */
+ if (lpfc_vmid_is_type_priority_tag(vport) && !(vport->vmid_flag &
+ LPFC_VMID_QFPA_CMPL)) {
+ vport->work_port_events |= WORKER_CHECK_VMID_ISSUE_QFPA;
+ return -EAGAIN;
+ }
+
+ /* 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_hashtable(vport, hash, uuid);
+
+ /* if found, check if its already registered */
+ if (vmp && vmp->flag & LPFC_VMID_REGISTERED) {
+ read_unlock(&vport->vmid_lock);
+ 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 */
+ read_unlock(&vport->vmid_lock);
+ rc = -EBUSY;
+ } else {
+ /* The vmid was not found in the hashtable. At this point, */
+ /* drop the read lock first before proceeding further */
+ read_unlock(&vport->vmid_lock);
+ /* start the process to obtain one as per the */
+ /* type of the vmid indicated */
+ write_lock(&vport->vmid_lock);
+ vmp = lpfc_get_vmid_from_hashtable(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 -EBUSY;
+ }
+
+ /* 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)
+ break;
+ }
+ if (i == vport->max_vmid)
+ vmp = NULL;
+ } else {
+ vmp = NULL;
+ }
+
+ if (!vmp) {
+ write_unlock(&vport->vmid_lock);
+ return -ENOMEM;
+ }
+
+ /* Add the vmid and register */
+ lpfc_put_vmid_in_hashtable(vport, hash, vmp);
+ vmp->vmid_len = len;
+ memcpy(vmp->host_vmid, uuid, vmp->vmid_len);
+ vmp->io_rd_cnt = 0;
+ vmp->io_wr_cnt = 0;
+ vmp->flag = LPFC_VMID_SLOT_USED;
+
+ 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));
+ if (!vmp->last_io_time) {
+ hash_del(&vmp->hnode);
+ vmp->flag = LPFC_VMID_SLOT_FREE;
+ write_unlock(&vport->vmid_lock);
+ return -EIO;
+ }
+
+ write_unlock(&vport->vmid_lock);
+
+ /* complete transaction with switch */
+ 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);
+ } else {
+ write_lock(&vport->vmid_lock);
+ hash_del(&vmp->hnode);
+ vmp->flag = LPFC_VMID_SLOT_FREE;
+ free_percpu(vmp->last_io_time);
+ write_unlock(&vport->vmid_lock);
+ return -EIO;
+ }
+
+ /* 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_fc_appid(cmd->request->bio);
+ }
+ return uuid;
+}
+
/**
* lpfc_queuecommand - scsi_host_template queuecommand entry point
* @shost: kernel scsi host pointer.
@@ -5288,6 +5442,7 @@ 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();
@@ -5415,6 +5570,25 @@ lpfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
}

+ /* 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);
--
2.26.2