[PATCH v8 10/16] lpfc: vmid: Functions to manage vmids

[Muneendra]

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

This patch contains the routines to save, retrieve and remove the vmids
from the data structure. A hash table is used to save the vmids and
the corresponding UUIDs associated with the application/VMs.

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

---
v8:
Added correct return value and error codes

v7:
No change

v6:
Added Forward declarations and functions to static

v5:
Changed Return code to non-numeric/Symbol

v4:
No change

v3:
No change

v2:
Ported the patch on top of 5.10/scsi-queue
---
 drivers/scsi/lpfc/lpfc_scsi.c | 148 ++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index e96e767faa2a..b71602878559 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -28,6 +28,7 @@
 #include <asm/unaligned.h>
 #include <linux/t10-pi.h>
 #include <linux/crc-t10dif.h>
+#include <linux/blk-cgroup.h>
 #include <net/checksum.h>
 
 #include <scsi/scsi.h>
@@ -86,6 +87,14 @@ static void
 lpfc_release_scsi_buf_s3(struct lpfc_hba *phba, struct lpfc_io_buf *psb);
 static int
 lpfc_prot_group_type(struct lpfc_hba *phba, struct scsi_cmnd *sc);
+static int
+lpfc_put_vmid_in_hashtable(struct lpfc_vport *vport, u32 hash,
+			   struct lpfc_vmid *vmp);
+static void lpfc_vmid_update_entry(struct lpfc_vport *vport, struct scsi_cmnd
+				   *cmd, struct lpfc_vmid *vmp,
+				   union lpfc_vmid_io_tag *tag);
+static void lpfc_vmid_assign_cs_ctl(struct lpfc_vport *vport,
+				    struct lpfc_vmid *vmid);
 
 static inline unsigned
 lpfc_cmd_blksize(struct scsi_cmnd *sc)
@@ -5131,6 +5140,145 @@ void lpfc_poll_timeout(struct timer_list *t)
 	}
 }
 
+/*
+ * lpfc_get_vmid_from_hastable - search the UUID in the hash table
+ * @vport: The virtual port for which this call is being executed.
+ * @hash: calculated hash value
+ * @buf: uuid associated with the VE
+ * Returns the vmid entry associated with the UUID
+ * Make sure to acquire the appropriate lock before invoking this routine.
+ */
+struct lpfc_vmid *lpfc_get_vmid_from_hastable(struct lpfc_vport *vport,
+					      u32 hash, u8 *buf)
+{
+	struct lpfc_vmid *vmp;
+	u16 count = 0;
+
+	while (count < LPFC_VMID_HASH_SIZE) {
+		vmp = vport->hash_table[hash];
+		if (vmp) {
+			if (strncmp(&vmp->host_vmid[0], buf, 16) == 0)
+				return vmp;
+		} else {
+			return NULL;
+		}
+		/* search the next available slot and continue till entry */
+		/* is found */
+		count++;
+		hash++;
+
+		/* or the end is reached */
+		if (hash == LPFC_VMID_HASH_SIZE)
+			hash = 0;
+	}
+	return NULL;
+}
+
+/*
+ * lpfc_put_vmid_from_hastable - put the VMID in the hash table
+ * @vport: The virtual port for which this call is being executed.
+ * @hash - calculated hash value
+ * @vmp: Pointer to a VMID entry representing a VM sending IO
+ *
+ * This routine will insert the newly acquired vmid entity in the hash table.
+ * Make sure to acquire the appropriate lock before invoking this routine.
+ */
+static int
+lpfc_put_vmid_in_hashtable(struct lpfc_vport *vport, u32 hash,
+			   struct lpfc_vmid *vmp)
+{
+	int count = 0;
+
+	while (count < LPFC_VMID_HASH_SIZE) {
+		if (!vport->hash_table[hash]) {
+			vport->hash_table[hash] = vmp;
+			vmp->hash_index = hash;
+			return 0;
+		}
+		/* if the slot is already occupied, a collision has occurred. */
+		/* Store in the next available slot */
+		count++;
+		hash++;
+		/* table is full */
+		if (hash == LPFC_VMID_HASH_SIZE)
+			hash = 0;
+	}
+	return -ENOMEM;
+}
+
+/*
+ * lpfc_vmid_hash_fn - creates a hash value of the UUID
+ * @vmid: uuid associated with the VE
+ * @len: length of the vmid string
+ * Returns the calculated hash value
+ */
+int lpfc_vmid_hash_fn(const char *vmid, int len)
+{
+	int c;
+	int hash = 0;
+
+	if (len == 0)
+		return 0;
+	while (len--) {
+		c = *vmid++;
+		if (c >= 'A' && c <= 'Z')
+			c += 'a' - 'A';
+
+		hash = (hash + (c << LPFC_VMID_HASH_SHIFT) +
+			(c >> LPFC_VMID_HASH_SHIFT)) * 19;
+	}
+
+	return hash & LPFC_VMID_HASH_MASK;
+}
+
+/*
+ * lpfc_vmid_update_entry - update the vmid entry in the hash table
+ * @vport: The virtual port for which this call is being executed.
+ * @cmd: address of scsi cmmd descriptor
+ * @vmp: Pointer to a VMID entry representing a VM sending IO
+ * @tag: VMID tag
+ */
+static void lpfc_vmid_update_entry(struct lpfc_vport *vport, struct scsi_cmnd
+				   *cmd, struct lpfc_vmid *vmp,
+				   union lpfc_vmid_io_tag *tag)
+{
+	u64 *lta;
+
+	if (vport->vmid_priority_tagging)
+		tag->cs_ctl_vmid = vmp->un.cs_ctl_vmid;
+	else
+		tag->app_id = vmp->un.app_id;
+
+	if (cmd->sc_data_direction == DMA_TO_DEVICE)
+		vmp->io_wr_cnt++;
+	else
+		vmp->io_rd_cnt++;
+
+	/* update the last access timestamp in the table */
+	lta = per_cpu_ptr(vmp->last_io_time, raw_smp_processor_id());
+	*lta = jiffies;
+}
+
+static void lpfc_vmid_assign_cs_ctl(struct lpfc_vport *vport,
+				    struct lpfc_vmid *vmid)
+{
+	u32 hash;
+	struct lpfc_vmid *pvmid;
+
+	if (vport->port_type == LPFC_PHYSICAL_PORT) {
+		vmid->un.cs_ctl_vmid = lpfc_vmid_get_cs_ctl(vport);
+	} else {
+		hash = lpfc_vmid_hash_fn(vmid->host_vmid, vmid->vmid_len);
+		pvmid =
+		    lpfc_get_vmid_from_hastable(vport->phba->pport, hash,
+						vmid->host_vmid);
+		if (pvmid)
+			vmid->un.cs_ctl_vmid = pvmid->un.cs_ctl_vmid;
+		else
+			vmid->un.cs_ctl_vmid = lpfc_vmid_get_cs_ctl(vport);
+	}
+}
+
 /**
  * lpfc_queuecommand - scsi_host_template queuecommand entry point
  * @shost: kernel scsi host pointer.
-- 
2.26.2