* [PATCH v2 2/3] ibmvscsi: redo driver work thread to use enum action states
2019-05-03 0:50 [PATCH v2 1/3] ibmvscsi: Wire up host_reset() in the drivers scsi_host_template Tyrel Datwyler
@ 2019-05-03 0:50 ` Tyrel Datwyler
2019-05-03 0:50 ` [PATCH v2 3/3] ibmvscsi: fix tripping of blk_mq_run_hw_queue WARN_ON Tyrel Datwyler
2019-05-30 1:32 ` [PATCH v2 1/3] ibmvscsi: Wire up host_reset() in the drivers scsi_host_template Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Tyrel Datwyler @ 2019-05-03 0:50 UTC (permalink / raw)
To: james.bottomley
Cc: Tyrel Datwyler, martin.petersen, linux-scsi, Tyrel Datwyler,
brking, linuxppc-dev
From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
The current implemenation relies on two flags in the drivers private host
structure to signal the need for a host reset or to reenable the CRQ after a
LPAR migration. This patch does away with those flags and introduces a single
action flag and defined enums for the supported kthread work actions. Lastly,
the if/else logic is replaced with a switch statement.
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
Changes in v2:
release/grab host_lock around reset/reenable calls
drivers/scsi/ibmvscsi/ibmvscsi.c | 61 ++++++++++++++++++++++----------
drivers/scsi/ibmvscsi/ibmvscsi.h | 9 +++--
2 files changed, 49 insertions(+), 21 deletions(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65fc8ca962c5..8df82c58e7b9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -828,7 +828,7 @@ static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
atomic_set(&hostdata->request_limit, 0);
purge_requests(hostdata, DID_ERROR);
- hostdata->reset_crq = 1;
+ hostdata->action = IBMVSCSI_HOST_ACTION_RESET;
wake_up(&hostdata->work_wait_q);
}
@@ -1797,7 +1797,7 @@ static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
/* We need to re-setup the interpartition connection */
dev_info(hostdata->dev, "Re-enabling adapter!\n");
hostdata->client_migrated = 1;
- hostdata->reenable_crq = 1;
+ hostdata->action = IBMVSCSI_HOST_ACTION_REENABLE;
purge_requests(hostdata, DID_REQUEUE);
wake_up(&hostdata->work_wait_q);
} else {
@@ -2116,48 +2116,71 @@ static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
{
+ unsigned long flags;
int rc;
char *action = "reset";
- if (hostdata->reset_crq) {
- smp_rmb();
- hostdata->reset_crq = 0;
-
+ spin_lock_irqsave(hostdata->host->host_lock, flags);
+ switch (hostdata->action) {
+ case IBMVSCSI_HOST_ACTION_NONE:
+ break;
+ case IBMVSCSI_HOST_ACTION_RESET:
+ spin_unlock_irqrestore(hostdata->host->host_lock, flags);
rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
+ spin_lock_irqsave(hostdata->host->host_lock, flags);
if (!rc)
rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
vio_enable_interrupts(to_vio_dev(hostdata->dev));
- } else if (hostdata->reenable_crq) {
- smp_rmb();
+ break;
+ case IBMVSCSI_HOST_ACTION_REENABLE:
action = "enable";
+ spin_unlock_irqrestore(hostdata->host->host_lock, flags);
rc = ibmvscsi_reenable_crq_queue(&hostdata->queue, hostdata);
- hostdata->reenable_crq = 0;
+ spin_lock_irqsave(hostdata->host->host_lock, flags);
if (!rc)
rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
- } else
- return;
+ break;
+ default:
+ break;
+ }
+
+ hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
if (rc) {
atomic_set(&hostdata->request_limit, -1);
dev_err(hostdata->dev, "error after %s\n", action);
}
+ spin_unlock_irqrestore(hostdata->host->host_lock, flags);
scsi_unblock_requests(hostdata->host);
}
-static int ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
+static int __ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
{
if (kthread_should_stop())
return 1;
- else if (hostdata->reset_crq) {
- smp_rmb();
- return 1;
- } else if (hostdata->reenable_crq) {
- smp_rmb();
- return 1;
+ switch (hostdata->action) {
+ case IBMVSCSI_HOST_ACTION_NONE:
+ return 0;
+ case IBMVSCSI_HOST_ACTION_RESET:
+ case IBMVSCSI_HOST_ACTION_REENABLE:
+ default:
+ break;
}
- return 0;
+ return 1;
+}
+
+static int ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
+{
+ unsigned long flags;
+ int rc;
+
+ spin_lock_irqsave(hostdata->host->host_lock, flags);
+ rc = __ibmvscsi_work_to_do(hostdata);
+ spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+
+ return rc;
}
static int ibmvscsi_work(void *data)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h
index 3a7875575616..04bcbc832dc9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.h
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
@@ -88,13 +88,18 @@ struct event_pool {
dma_addr_t iu_token;
};
+enum ibmvscsi_host_action {
+ IBMVSCSI_HOST_ACTION_NONE = 0,
+ IBMVSCSI_HOST_ACTION_RESET,
+ IBMVSCSI_HOST_ACTION_REENABLE,
+};
+
/* all driver data associated with a host adapter */
struct ibmvscsi_host_data {
struct list_head host_list;
atomic_t request_limit;
int client_migrated;
- int reset_crq;
- int reenable_crq;
+ enum ibmvscsi_host_action action;
struct device *dev;
struct event_pool pool;
struct crq_queue queue;
--
2.18.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 3/3] ibmvscsi: fix tripping of blk_mq_run_hw_queue WARN_ON
2019-05-03 0:50 [PATCH v2 1/3] ibmvscsi: Wire up host_reset() in the drivers scsi_host_template Tyrel Datwyler
2019-05-03 0:50 ` [PATCH v2 2/3] ibmvscsi: redo driver work thread to use enum action states Tyrel Datwyler
@ 2019-05-03 0:50 ` Tyrel Datwyler
2019-05-30 1:32 ` [PATCH v2 1/3] ibmvscsi: Wire up host_reset() in the drivers scsi_host_template Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Tyrel Datwyler @ 2019-05-03 0:50 UTC (permalink / raw)
To: james.bottomley
Cc: Tyrel Datwyler, martin.petersen, linux-scsi, Tyrel Datwyler,
brking, linuxppc-dev
From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
After a successful SRP login response we call scsi_unblock_requests() to
kick any pending IO's. The callback to process this SRP response happens in
a tasklet and therefore is in softirq context. The result of such is
that when blk-mq is enabled it is no longer safe to call
scsi_unblock_requests() from this context. The result of duing so
triggers the following WARN_ON splat in dmesg after a host reset or CRQ
reenablement.
WARNING: CPU: 0 PID: 0 at block/blk-mq.c:1375 __blk_mq_run_hw_queue+0x120/0x180
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.0.0-rc8 #4
NIP [c0000000009771e0] __blk_mq_run_hw_queue+0x120/0x180
LR [c000000000977484] __blk_mq_delay_run_hw_queue+0x244/0x250
Call Trace:
__blk_mq_delay_run_hw_queue+0x244/0x250
blk_mq_run_hw_queue+0x8c/0x1c0
blk_mq_run_hw_queues+0x60/0x90
scsi_run_queue+0x1e4/0x3b0
scsi_run_host_queues+0x48/0x80
login_rsp+0xb0/0x100
ibmvscsi_handle_crq+0x30c/0x3e0
ibmvscsi_task+0x54/0xe0
tasklet_action_common.isra.3+0xc4/0x1a0
__do_softirq+0x174/0x3f4
irq_exit+0xf0/0x120
__do_irq+0xb0/0x210
call_do_irq+0x14/0x24
do_IRQ+0x9c/0x130
hardware_interrupt_common+0x14c/0x150
This patch fixes the issue by introducing a new host action for
unblocking the scsi requests in our seperate work thread.
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
Changes in v2:
no change
drivers/scsi/ibmvscsi/ibmvscsi.c | 5 ++++-
drivers/scsi/ibmvscsi/ibmvscsi.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 8df82c58e7b9..727c31dc11a0 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -1179,7 +1179,8 @@ static void login_rsp(struct srp_event_struct *evt_struct)
be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta));
/* If we had any pending I/Os, kick them */
- scsi_unblock_requests(hostdata->host);
+ hostdata->action = IBMVSCSI_HOST_ACTION_UNBLOCK;
+ wake_up(&hostdata->work_wait_q);
}
/**
@@ -2123,6 +2124,7 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
spin_lock_irqsave(hostdata->host->host_lock, flags);
switch (hostdata->action) {
case IBMVSCSI_HOST_ACTION_NONE:
+ case IBMVSCSI_HOST_ACTION_UNBLOCK:
break;
case IBMVSCSI_HOST_ACTION_RESET:
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
@@ -2164,6 +2166,7 @@ static int __ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
return 0;
case IBMVSCSI_HOST_ACTION_RESET:
case IBMVSCSI_HOST_ACTION_REENABLE:
+ case IBMVSCSI_HOST_ACTION_UNBLOCK:
default:
break;
}
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h
index 04bcbc832dc9..d9bf502334ba 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.h
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
@@ -92,6 +92,7 @@ enum ibmvscsi_host_action {
IBMVSCSI_HOST_ACTION_NONE = 0,
IBMVSCSI_HOST_ACTION_RESET,
IBMVSCSI_HOST_ACTION_REENABLE,
+ IBMVSCSI_HOST_ACTION_UNBLOCK,
};
/* all driver data associated with a host adapter */
--
2.18.1
^ permalink raw reply related [flat|nested] 4+ messages in thread