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[SCSI] ibmvscsi: Add eh_host_reset_handler
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Adds an eh_host_reset_handler to ibmvscsi which resets the connection
to the vscsi server. This patch also adds a timer to internally
issues commands to prevent client hangs in the case of a misbehaving
server. Tested by modifying the VIOS such that it would occasionally
drop one or more request in sequence.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Brian King authored and James Bottomley committed Jun 17, 2007
1 parent 6c0a60e commit 3d0e91f
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Showing 2 changed files with 107 additions and 30 deletions.
136 changes: 106 additions & 30 deletions drivers/scsi/ibmvscsi/ibmvscsi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -509,19 +509,85 @@ static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
return map_single_data(cmd, srp_cmd, dev);
}

/**
* purge_requests: Our virtual adapter just shut down. purge any sent requests
* @hostdata: the adapter
*/
static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
{
struct srp_event_struct *tmp_evt, *pos;
unsigned long flags;

spin_lock_irqsave(hostdata->host->host_lock, flags);
list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
list_del(&tmp_evt->list);
del_timer(&tmp_evt->timer);
if (tmp_evt->cmnd) {
tmp_evt->cmnd->result = (error_code << 16);
unmap_cmd_data(&tmp_evt->iu.srp.cmd,
tmp_evt,
tmp_evt->hostdata->dev);
if (tmp_evt->cmnd_done)
tmp_evt->cmnd_done(tmp_evt->cmnd);
} else if (tmp_evt->done)
tmp_evt->done(tmp_evt);
free_event_struct(&tmp_evt->hostdata->pool, tmp_evt);
}
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
}

/**
* ibmvscsi_reset_host - Reset the connection to the server
* @hostdata: struct ibmvscsi_host_data to reset
*/
static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
{
scsi_block_requests(hostdata->host);
atomic_set(&hostdata->request_limit, 0);

purge_requests(hostdata, DID_ERROR);
if ((ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata)) ||
(ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0)) ||
(vio_enable_interrupts(to_vio_dev(hostdata->dev)))) {
atomic_set(&hostdata->request_limit, -1);
dev_err(hostdata->dev, "error after reset\n");
}

scsi_unblock_requests(hostdata->host);
}

/**
* ibmvscsi_timeout - Internal command timeout handler
* @evt_struct: struct srp_event_struct that timed out
*
* Called when an internally generated command times out
*/
static void ibmvscsi_timeout(struct srp_event_struct *evt_struct)
{
struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;

dev_err(hostdata->dev, "Command timed out (%x). Resetting connection\n",
evt_struct->iu.srp.cmd.opcode);

ibmvscsi_reset_host(hostdata);
}


/* ------------------------------------------------------------
* Routines for sending and receiving SRPs
*/
/**
* ibmvscsi_send_srp_event: - Transforms event to u64 array and calls send_crq()
* @evt_struct: evt_struct to be sent
* @hostdata: ibmvscsi_host_data of host
* @timeout: timeout in seconds - 0 means do not time command
*
* Returns the value returned from ibmvscsi_send_crq(). (Zero for success)
* Note that this routine assumes that host_lock is held for synchronization
*/
static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
struct ibmvscsi_host_data *hostdata)
struct ibmvscsi_host_data *hostdata,
unsigned long timeout)
{
u64 *crq_as_u64 = (u64 *) &evt_struct->crq;
int request_status;
Expand Down Expand Up @@ -577,9 +643,18 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
*/
list_add_tail(&evt_struct->list, &hostdata->sent);

init_timer(&evt_struct->timer);
if (timeout) {
evt_struct->timer.data = (unsigned long) evt_struct;
evt_struct->timer.expires = jiffies + (timeout * HZ);
evt_struct->timer.function = (void (*)(unsigned long))ibmvscsi_timeout;
add_timer(&evt_struct->timer);
}

if ((rc =
ibmvscsi_send_crq(hostdata, crq_as_u64[0], crq_as_u64[1])) != 0) {
list_del(&evt_struct->list);
del_timer(&evt_struct->timer);

dev_err(hostdata->dev, "send error %d\n", rc);
atomic_inc(&hostdata->request_limit);
Expand Down Expand Up @@ -709,7 +784,7 @@ static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
offsetof(struct srp_indirect_buf, desc_list);
}

return ibmvscsi_send_srp_event(evt_struct, hostdata);
return ibmvscsi_send_srp_event(evt_struct, hostdata, 0);
}

/* ------------------------------------------------------------
Expand Down Expand Up @@ -800,7 +875,7 @@ static void send_mad_adapter_info(struct ibmvscsi_host_data *hostdata)
return;
}

if (ibmvscsi_send_srp_event(evt_struct, hostdata)) {
if (ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2)) {
dev_err(hostdata->dev, "couldn't send ADAPTER_INFO_REQ!\n");
dma_unmap_single(hostdata->dev,
addr,
Expand Down Expand Up @@ -889,7 +964,7 @@ static int send_srp_login(struct ibmvscsi_host_data *hostdata)
*/
atomic_set(&hostdata->request_limit, 1);

rc = ibmvscsi_send_srp_event(evt_struct, hostdata);
rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
dev_info(hostdata->dev, "sent SRP login\n");
return rc;
Expand Down Expand Up @@ -969,7 +1044,7 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)

evt->sync_srp = &srp_rsp;
init_completion(&evt->comp);
rsp_rc = ibmvscsi_send_srp_event(evt, hostdata);
rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
if (rsp_rc != 0) {
sdev_printk(KERN_ERR, cmd->device,
Expand Down Expand Up @@ -1077,7 +1152,7 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)

evt->sync_srp = &srp_rsp;
init_completion(&evt->comp);
rsp_rc = ibmvscsi_send_srp_event(evt, hostdata);
rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
if (rsp_rc != 0) {
sdev_printk(KERN_ERR, cmd->device,
Expand Down Expand Up @@ -1133,32 +1208,30 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
}

/**
* purge_requests: Our virtual adapter just shut down. purge any sent requests
* @hostdata: the adapter
*/
static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
* ibmvscsi_eh_host_reset_handler - Reset the connection to the server
* @cmd: struct scsi_cmnd having problems
*/
static int ibmvscsi_eh_host_reset_handler(struct scsi_cmnd *cmd)
{
struct srp_event_struct *tmp_evt, *pos;
unsigned long flags;
unsigned long wait_switch = 0;
struct ibmvscsi_host_data *hostdata =
(struct ibmvscsi_host_data *)cmd->device->host->hostdata;

spin_lock_irqsave(hostdata->host->host_lock, flags);
list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
list_del(&tmp_evt->list);
if (tmp_evt->cmnd) {
tmp_evt->cmnd->result = (error_code << 16);
unmap_cmd_data(&tmp_evt->iu.srp.cmd,
tmp_evt,
tmp_evt->hostdata->dev);
if (tmp_evt->cmnd_done)
tmp_evt->cmnd_done(tmp_evt->cmnd);
} else {
if (tmp_evt->done) {
tmp_evt->done(tmp_evt);
}
}
free_event_struct(&tmp_evt->hostdata->pool, tmp_evt);
dev_err(hostdata->dev, "Resetting connection due to error recovery\n");

ibmvscsi_reset_host(hostdata);

for (wait_switch = jiffies + (init_timeout * HZ);
time_before(jiffies, wait_switch) &&
atomic_read(&hostdata->request_limit) < 2;) {

msleep(10);
}
spin_unlock_irqrestore(hostdata->host->host_lock, flags);

if (atomic_read(&hostdata->request_limit) <= 0)
return FAILED;

return SUCCESS;
}

/**
Expand Down Expand Up @@ -1258,6 +1331,8 @@ void ibmvscsi_handle_crq(struct viosrp_crq *crq,
atomic_add(evt_struct->xfer_iu->srp.rsp.req_lim_delta,
&hostdata->request_limit);

del_timer(&evt_struct->timer);

if (evt_struct->done)
evt_struct->done(evt_struct);
else
Expand Down Expand Up @@ -1313,7 +1388,7 @@ static int ibmvscsi_do_host_config(struct ibmvscsi_host_data *hostdata,
}

init_completion(&evt_struct->comp);
rc = ibmvscsi_send_srp_event(evt_struct, hostdata);
rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
if (rc == 0)
wait_for_completion(&evt_struct->comp);
dma_unmap_single(hostdata->dev, addr, length, DMA_BIDIRECTIONAL);
Expand Down Expand Up @@ -1504,6 +1579,7 @@ static struct scsi_host_template driver_template = {
.queuecommand = ibmvscsi_queuecommand,
.eh_abort_handler = ibmvscsi_eh_abort_handler,
.eh_device_reset_handler = ibmvscsi_eh_device_reset_handler,
.eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
.slave_configure = ibmvscsi_slave_configure,
.change_queue_depth = ibmvscsi_change_queue_depth,
.cmd_per_lun = 16,
Expand Down
1 change: 1 addition & 0 deletions drivers/scsi/ibmvscsi/ibmvscsi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,7 @@ struct srp_event_struct {
union viosrp_iu iu;
void (*cmnd_done) (struct scsi_cmnd *);
struct completion comp;
struct timer_list timer;
union viosrp_iu *sync_srp;
struct srp_direct_buf *ext_list;
dma_addr_t ext_list_token;
Expand Down

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