[PATCH 4.9 50/93] scsi: ibmvscsis: Synchronize cmds at tpg_enable_store time

From: Greg Kroah-Hartman
Date: Mon Mar 20 2017 - 14:30:24 EST

4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michael Cyr <mikecyr@xxxxxxxxxx>

[ Upstream commit c9b3379f60a83288a5e2f8ea75476460978689b0 ]

This patch changes the way the IBM vSCSI server driver manages its
Command/Response Queue (CRQ). We used to register the CRQ with phyp at
probe time. Now we wait until tpg_enable_store. Similarly, when
tpg_enable_store is called to "disable" (i.e. the stored value is 0),
we unregister the queue with phyp.

One consquence to this is that we have no need for the PART_UP_WAIT_ENAB
state, since we can't get an Init Message from the client in our CRQ if
we're waiting to be enabled, since we haven't registered the queue yet.

Signed-off-by: Michael Cyr <mikecyr@xxxxxxxxxx>
Signed-off-by: Bryant G. Ly <bryantly@xxxxxxxxxxxxxxxxxx>
Tested-by: Steven Royer <seroyer@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 224 +++++--------------------------
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h | 2
2 files changed, 38 insertions(+), 188 deletions(-)

--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -62,8 +62,6 @@ static long ibmvscsis_parse_command(stru

static void ibmvscsis_adapter_idle(struct scsi_info *vscsi);

-static void ibmvscsis_reset_queue(struct scsi_info *vscsi, uint new_state);
-
static void ibmvscsis_determine_resid(struct se_cmd *se_cmd,
struct srp_rsp *rsp)
{
@@ -418,7 +416,6 @@ static void ibmvscsis_disconnect(struct
proc_work);
u16 new_state;
bool wait_idle = false;
- long rc = ADAPT_SUCCESS;

spin_lock_bh(&vscsi->intr_lock);
new_state = vscsi->new_state;
@@ -471,30 +468,12 @@ static void ibmvscsis_disconnect(struct
vscsi->state = new_state;
break;

- /*
- * If this is a transition into an error state.
- * a client is attempting to establish a connection
- * and has violated the RPA protocol.
- * There can be nothing pending on the adapter although
- * there can be requests in the command queue.
- */
case WAIT_ENABLED:
- case PART_UP_WAIT_ENAB:
switch (new_state) {
+ /* should never happen */
case ERR_DISCONNECT:
- vscsi->flags |= RESPONSE_Q_DOWN;
- vscsi->state = new_state;
- vscsi->flags &= ~(SCHEDULE_DISCONNECT |
- DISCONNECT_SCHEDULED);
- ibmvscsis_free_command_q(vscsi);
- break;
case ERR_DISCONNECT_RECONNECT:
- ibmvscsis_reset_queue(vscsi, WAIT_ENABLED);
- break;
-
- /* should never happen */
case WAIT_IDLE:
- rc = ERROR;
dev_err(&vscsi->dev, "disconnect: invalid state %d for WAIT_IDLE\n",
vscsi->state);
break;
@@ -631,7 +610,6 @@ static void ibmvscsis_post_disconnect(st
break;

case WAIT_ENABLED:
- case PART_UP_WAIT_ENAB:
case WAIT_IDLE:
case WAIT_CONNECTION:
case CONNECTED:
@@ -676,7 +654,6 @@ static long ibmvscsis_handle_init_compl_
case SRP_PROCESSING:
case CONNECTED:
case WAIT_ENABLED:
- case PART_UP_WAIT_ENAB:
default:
rc = ERROR;
dev_err(&vscsi->dev, "init_msg: invalid state %d to get init compl msg\n",
@@ -699,10 +676,6 @@ static long ibmvscsis_handle_init_msg(st
long rc = ADAPT_SUCCESS;

switch (vscsi->state) {
- case WAIT_ENABLED:
- vscsi->state = PART_UP_WAIT_ENAB;
- break;
-
case WAIT_CONNECTION:
rc = ibmvscsis_send_init_message(vscsi, INIT_COMPLETE_MSG);
switch (rc) {
@@ -738,7 +711,7 @@ static long ibmvscsis_handle_init_msg(st
case UNCONFIGURING:
break;

- case PART_UP_WAIT_ENAB:
+ case WAIT_ENABLED:
case CONNECTED:
case SRP_PROCESSING:
case WAIT_IDLE:
@@ -801,11 +774,10 @@ static long ibmvscsis_init_msg(struct sc
/**
* ibmvscsis_establish_new_q() - Establish new CRQ queue
* @vscsi: Pointer to our adapter structure
- * @new_state: New state being established after resetting the queue
*
* Must be called with interrupt lock held.
*/
-static long ibmvscsis_establish_new_q(struct scsi_info *vscsi, uint new_state)
+static long ibmvscsis_establish_new_q(struct scsi_info *vscsi)
{
long rc = ADAPT_SUCCESS;
uint format;
@@ -817,19 +789,19 @@ static long ibmvscsis_establish_new_q(st

rc = vio_enable_interrupts(vscsi->dma_dev);
if (rc) {
- pr_warn("reset_queue: failed to enable interrupts, rc %ld\n",
+ pr_warn("establish_new_q: failed to enable interrupts, rc %ld\n",
rc);
return rc;
}

rc = ibmvscsis_check_init_msg(vscsi, &format);
if (rc) {
- dev_err(&vscsi->dev, "reset_queue: check_init_msg failed, rc %ld\n",
+ dev_err(&vscsi->dev, "establish_new_q: check_init_msg failed, rc %ld\n",
rc);
return rc;
}

- if (format == UNUSED_FORMAT && new_state == WAIT_CONNECTION) {
+ if (format == UNUSED_FORMAT) {
rc = ibmvscsis_send_init_message(vscsi, INIT_MSG);
switch (rc) {
case H_SUCCESS:
@@ -847,6 +819,8 @@ static long ibmvscsis_establish_new_q(st
rc = H_HARDWARE;
break;
}
+ } else if (format == INIT_MSG) {
+ rc = ibmvscsis_handle_init_msg(vscsi);
}

return rc;
@@ -855,7 +829,6 @@ static long ibmvscsis_establish_new_q(st
/**
* ibmvscsis_reset_queue() - Reset CRQ Queue
* @vscsi: Pointer to our adapter structure
- * @new_state: New state to establish after resetting the queue
*
* This function calls h_free_q and then calls h_reg_q and does all
* of the bookkeeping to get us back to where we can communicate.
@@ -872,7 +845,7 @@ static long ibmvscsis_establish_new_q(st
* EXECUTION ENVIRONMENT:
* Process environment, called with interrupt lock held
*/
-static void ibmvscsis_reset_queue(struct scsi_info *vscsi, uint new_state)
+static void ibmvscsis_reset_queue(struct scsi_info *vscsi)
{
int bytes;
long rc = ADAPT_SUCCESS;
@@ -885,19 +858,18 @@ static void ibmvscsis_reset_queue(struct
vscsi->rsp_q_timer.timer_pops = 0;
vscsi->debit = 0;
vscsi->credit = 0;
- vscsi->state = new_state;
+ vscsi->state = WAIT_CONNECTION;
vio_enable_interrupts(vscsi->dma_dev);
} else {
rc = ibmvscsis_free_command_q(vscsi);
if (rc == ADAPT_SUCCESS) {
- vscsi->state = new_state;
+ vscsi->state = WAIT_CONNECTION;

bytes = vscsi->cmd_q.size * PAGE_SIZE;
rc = h_reg_crq(vscsi->dds.unit_id,
vscsi->cmd_q.crq_token, bytes);
if (rc == H_CLOSED || rc == H_SUCCESS) {
- rc = ibmvscsis_establish_new_q(vscsi,
- new_state);
+ rc = ibmvscsis_establish_new_q(vscsi);
}

if (rc != ADAPT_SUCCESS) {
@@ -1016,10 +988,6 @@ static long ibmvscsis_trans_event(struct
TRANS_EVENT));
break;

- case PART_UP_WAIT_ENAB:
- vscsi->state = WAIT_ENABLED;
- break;
-
case SRP_PROCESSING:
if ((vscsi->debit > 0) ||
!list_empty(&vscsi->schedule_q) ||
@@ -1220,15 +1188,18 @@ static void ibmvscsis_adapter_idle(struc

switch (vscsi->state) {
case ERR_DISCONNECT_RECONNECT:
- ibmvscsis_reset_queue(vscsi, WAIT_CONNECTION);
+ ibmvscsis_reset_queue(vscsi);
pr_debug("adapter_idle, disc_rec: flags 0x%x\n", vscsi->flags);
break;

case ERR_DISCONNECT:
ibmvscsis_free_command_q(vscsi);
- vscsi->flags &= ~DISCONNECT_SCHEDULED;
+ vscsi->flags &= ~(SCHEDULE_DISCONNECT | DISCONNECT_SCHEDULED);
vscsi->flags |= RESPONSE_Q_DOWN;
- vscsi->state = ERR_DISCONNECTED;
+ if (vscsi->tport.enabled)
+ vscsi->state = ERR_DISCONNECTED;
+ else
+ vscsi->state = WAIT_ENABLED;
pr_debug("adapter_idle, disc: flags 0x%x, state 0x%hx\n",
vscsi->flags, vscsi->state);
break;
@@ -1773,8 +1744,8 @@ static void ibmvscsis_send_messages(stru
be64_to_cpu(msg_hi),
be64_to_cpu(cmd->rsp.tag));

- pr_debug("send_messages: tag 0x%llx, rc %ld\n",
- be64_to_cpu(cmd->rsp.tag), rc);
+ pr_debug("send_messages: cmd %p, tag 0x%llx, rc %ld\n",
+ cmd, be64_to_cpu(cmd->rsp.tag), rc);

/* if all ok free up the command element resources */
if (rc == H_SUCCESS) {
@@ -2788,36 +2759,6 @@ static irqreturn_t ibmvscsis_interrupt(i
}

/**
- * ibmvscsis_check_q() - Helper function to Check Init Message Valid
- * @vscsi: Pointer to our adapter structure
- *
- * Checks if a initialize message was queued by the initiatior
- * while the timing window was open. This function is called from
- * probe after the CRQ is created and interrupts are enabled.
- * It would only be used by adapters who wait for some event before
- * completing the init handshake with the client. For ibmvscsi, this
- * event is waiting for the port to be enabled.
- *
- * EXECUTION ENVIRONMENT:
- * Process level only, interrupt lock held
- */
-static long ibmvscsis_check_q(struct scsi_info *vscsi)
-{
- uint format;
- long rc;
-
- rc = ibmvscsis_check_init_msg(vscsi, &format);
- if (rc)
- ibmvscsis_post_disconnect(vscsi, ERR_DISCONNECT_RECONNECT, 0);
- else if (format == UNUSED_FORMAT)
- vscsi->state = WAIT_ENABLED;
- else
- vscsi->state = PART_UP_WAIT_ENAB;
-
- return rc;
-}
-
-/**
* ibmvscsis_enable_change_state() - Set new state based on enabled status
* @vscsi: Pointer to our adapter structure
*
@@ -2828,77 +2769,19 @@ static long ibmvscsis_check_q(struct scs
*/
static long ibmvscsis_enable_change_state(struct scsi_info *vscsi)
{
+ int bytes;
long rc = ADAPT_SUCCESS;

-handle_state_change:
- switch (vscsi->state) {
- case WAIT_ENABLED:
- rc = ibmvscsis_send_init_message(vscsi, INIT_MSG);
- switch (rc) {
- case H_SUCCESS:
- case H_DROPPED:
- case H_CLOSED:
- vscsi->state = WAIT_CONNECTION;
- rc = ADAPT_SUCCESS;
- break;
-
- case H_PARAMETER:
- break;
-
- case H_HARDWARE:
- break;
-
- default:
- vscsi->state = UNDEFINED;
- rc = H_HARDWARE;
- break;
- }
- break;
- case PART_UP_WAIT_ENAB:
- rc = ibmvscsis_send_init_message(vscsi, INIT_COMPLETE_MSG);
- switch (rc) {
- case H_SUCCESS:
- vscsi->state = CONNECTED;
- rc = ADAPT_SUCCESS;
- break;
-
- case H_DROPPED:
- case H_CLOSED:
- vscsi->state = WAIT_ENABLED;
- goto handle_state_change;
-
- case H_PARAMETER:
- break;
-
- case H_HARDWARE:
- break;
-
- default:
- rc = H_HARDWARE;
- break;
- }
- break;
-
- case WAIT_CONNECTION:
- case WAIT_IDLE:
- case SRP_PROCESSING:
- case CONNECTED:
- rc = ADAPT_SUCCESS;
- break;
- /* should not be able to get here */
- case UNCONFIGURING:
- rc = ERROR;
- vscsi->state = UNDEFINED;
- break;
+ bytes = vscsi->cmd_q.size * PAGE_SIZE;
+ rc = h_reg_crq(vscsi->dds.unit_id, vscsi->cmd_q.crq_token, bytes);
+ if (rc == H_CLOSED || rc == H_SUCCESS) {
+ vscsi->state = WAIT_CONNECTION;
+ rc = ibmvscsis_establish_new_q(vscsi);
+ }

- /* driver should never allow this to happen */
- case ERR_DISCONNECT:
- case ERR_DISCONNECT_RECONNECT:
- default:
- dev_err(&vscsi->dev, "in invalid state %d during enable_change_state\n",
- vscsi->state);
- rc = ADAPT_SUCCESS;
- break;
+ if (rc != ADAPT_SUCCESS) {
+ vscsi->state = ERR_DISCONNECTED;
+ vscsi->flags |= RESPONSE_Q_DOWN;
}

return rc;
@@ -2918,7 +2801,6 @@ handle_state_change:
*/
static long ibmvscsis_create_command_q(struct scsi_info *vscsi, int num_cmds)
{
- long rc = 0;
int pages;
struct vio_dev *vdev = vscsi->dma_dev;

@@ -2942,22 +2824,7 @@ static long ibmvscsis_create_command_q(s
return -ENOMEM;
}

- rc = h_reg_crq(vscsi->dds.unit_id, vscsi->cmd_q.crq_token, PAGE_SIZE);
- if (rc) {
- if (rc == H_CLOSED) {
- vscsi->state = WAIT_ENABLED;
- rc = 0;
- } else {
- dma_unmap_single(&vdev->dev, vscsi->cmd_q.crq_token,
- PAGE_SIZE, DMA_BIDIRECTIONAL);
- free_page((unsigned long)vscsi->cmd_q.base_addr);
- rc = -ENODEV;
- }
- } else {
- vscsi->state = WAIT_ENABLED;
- }
-
- return rc;
+ return 0;
}

/**
@@ -3491,31 +3358,12 @@ static int ibmvscsis_probe(struct vio_de
goto destroy_WQ;
}

- spin_lock_bh(&vscsi->intr_lock);
- vio_enable_interrupts(vdev);
- if (rc) {
- dev_err(&vscsi->dev, "enabling interrupts failed, rc %d\n", rc);
- rc = -ENODEV;
- spin_unlock_bh(&vscsi->intr_lock);
- goto free_irq;
- }
-
- if (ibmvscsis_check_q(vscsi)) {
- rc = ERROR;
- dev_err(&vscsi->dev, "probe: check_q failed, rc %d\n", rc);
- spin_unlock_bh(&vscsi->intr_lock);
- goto disable_interrupt;
- }
- spin_unlock_bh(&vscsi->intr_lock);
+ vscsi->state = WAIT_ENABLED;

dev_set_drvdata(&vdev->dev, vscsi);

return 0;

-disable_interrupt:
- vio_disable_interrupts(vdev);
-free_irq:
- free_irq(vdev->irq, vscsi);
destroy_WQ:
destroy_workqueue(vscsi->work_q);
unmap_buf:
@@ -3909,18 +3757,22 @@ static ssize_t ibmvscsis_tpg_enable_stor
}

if (tmp) {
- tport->enabled = true;
spin_lock_bh(&vscsi->intr_lock);
+ tport->enabled = true;
lrc = ibmvscsis_enable_change_state(vscsi);
if (lrc)
pr_err("enable_change_state failed, rc %ld state %d\n",
lrc, vscsi->state);
spin_unlock_bh(&vscsi->intr_lock);
} else {
+ spin_lock_bh(&vscsi->intr_lock);
tport->enabled = false;
+ /* This simulates the server going down */
+ ibmvscsis_post_disconnect(vscsi, ERR_DISCONNECT, 0);
+ spin_unlock_bh(&vscsi->intr_lock);
}

- pr_debug("tpg_enable_store, state %d\n", vscsi->state);
+ pr_debug("tpg_enable_store, tmp %ld, state %d\n", tmp, vscsi->state);

return count;
}
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
@@ -204,8 +204,6 @@ struct scsi_info {
struct list_head waiting_rsp;
#define NO_QUEUE 0x00
#define WAIT_ENABLED 0X01
- /* driver has received an initialize command */
-#define PART_UP_WAIT_ENAB 0x02
#define WAIT_CONNECTION 0x04
/* have established a connection */
#define CONNECTED 0x08