This fixes a softlockup seen on resume. During resume, the CRQ
must be reenabled. However, the H_ENABLE_CRQ hcall used to do
this may return H_BUSY or H_LONG_BUSY. When this happens, the
caller is expected to retry later. This patch changes a simple
loop, which was causing the softlockup, to a loop at task level
which sleeps between retries rather than simply spinning.
Signed-off-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>
---
drivers/scsi/ibmvscsi/ibmvscsi.c | 117 ++++++++++++++++++++++++++++----------
drivers/scsi/ibmvscsi/ibmvscsi.h | 4 +
drivers/scsi/ibmvscsi/rpa_vscsi.c | 16 ++++-
3 files changed, 106 insertions(+), 31 deletions(-)
diff -puN drivers/scsi/ibmvscsi/ibmvscsi.h~ibmvscsi_reenable_sleep drivers/scsi/ibmvscsi/ibmvscsi.h
--- linux-2.6/drivers/scsi/ibmvscsi/ibmvscsi.h~ibmvscsi_reenable_sleep 2010-06-10 12:08:44.000000000 -0500
+++ linux-2.6-bjking1/drivers/scsi/ibmvscsi/ibmvscsi.h 2010-06-10 12:08:44.000000000 -0500
@@ -91,12 +91,16 @@ struct event_pool {
struct ibmvscsi_host_data {
atomic_t request_limit;
int client_migrated;
+ int reset_crq;
+ int reenable_crq;
struct device *dev;
struct event_pool pool;
struct crq_queue queue;
struct tasklet_struct srp_task;
struct list_head sent;
struct Scsi_Host *host;
+ struct task_struct *work_thread;
+ wait_queue_head_t work_wait_q;
struct mad_adapter_info_data madapter_info;
struct capabilities caps;
dma_addr_t caps_addr;
diff -puN drivers/scsi/ibmvscsi/ibmvscsi.c~ibmvscsi_reenable_sleep drivers/scsi/ibmvscsi/ibmvscsi.c
--- linux-2.6/drivers/scsi/ibmvscsi/ibmvscsi.c~ibmvscsi_reenable_sleep 2010-06-10 12:08:44.000000000 -0500
+++ linux-2.6-bjking1/drivers/scsi/ibmvscsi/ibmvscsi.c 2010-06-10 12:17:02.000000000 -0500
@@ -73,6 +73,7 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/pm.h>
+#include <linux/kthread.h>
#include <asm/firmware.h>
#include <asm/vio.h>
#include <scsi/scsi.h>
@@ -504,14 +505,8 @@ static void ibmvscsi_reset_host(struct i
atomic_set(&hostdata->request_limit, 0);
purge_requests(hostdata, DID_ERROR);
- if ((ibmvscsi_ops->reset_crq_queue(&hostdata->queue, hostdata)) ||
- (ibmvscsi_ops->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);
+ hostdata->reset_crq = 1;
+ wake_up(&hostdata->work_wait_q);
}
/**
@@ -1462,30 +1457,14 @@ void ibmvscsi_handle_crq(struct viosrp_c
/* We need to re-setup the interpartition connection */
dev_info(hostdata->dev, "Re-enabling adapter!\n");
hostdata->client_migrated = 1;
+ hostdata->reenable_crq = 1;
purge_requests(hostdata, DID_REQUEUE);
- if ((ibmvscsi_ops->reenable_crq_queue(&hostdata->queue,
- hostdata)) ||
- (ibmvscsi_ops->send_crq(hostdata,
- 0xC001000000000000LL, 0))) {
- atomic_set(&hostdata->request_limit,
- -1);
- dev_err(hostdata->dev, "error after enable\n");
- }
+ wake_up(&hostdata->work_wait_q);
} else {
dev_err(hostdata->dev, "Virtual adapter failed rc %d!\n",
crq->format);
-
- purge_requests(hostdata, DID_ERROR);
- if ((ibmvscsi_ops->reset_crq_queue(&hostdata->queue,
- hostdata)) ||
- (ibmvscsi_ops->send_crq(hostdata,
- 0xC001000000000000LL, 0))) {
- atomic_set(&hostdata->request_limit,
- -1);
- dev_err(hostdata->dev, "error after reset\n");
- }
+ ibmvscsi_reset_host(hostdata);
}
- scsi_unblock_requests(hostdata->host);
return;
case 0x80: /* real payload */
break;
@@ -1850,6 +1829,75 @@ static unsigned long ibmvscsi_get_desire
return desired_io;
}
+static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
+{
+ int rc;
+ char *action = "reset";
+
+ if (hostdata->reset_crq) {
+ smp_rmb();
+ hostdata->reset_crq = 0;
+
+ rc = ibmvscsi_ops->reset_crq_queue(&hostdata->queue, hostdata);
+ if (!rc)
+ rc = ibmvscsi_ops->send_crq(hostdata, 0xC001000000000000LL, 0);
+ if (!rc)
+ rc = vio_enable_interrupts(to_vio_dev(hostdata->dev));
+ } else if (hostdata->reenable_crq) {
+ smp_rmb();
+ action = "enable";
+ rc = ibmvscsi_ops->reenable_crq_queue(&hostdata->queue, hostdata);
+ hostdata->reenable_crq = 0;
+ if (!rc)
+ rc = ibmvscsi_ops->send_crq(hostdata, 0xC001000000000000LL, 0);
+ } else
+ return;
+
+ if (rc) {
+ atomic_set(&hostdata->request_limit, -1);
+ dev_err(hostdata->dev, "error after %s\n", action);
+ }
+
+ scsi_unblock_requests(hostdata->host);
+}
+
+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;
+ }
+
+ return 0;
+}
+
+static int ibmvscsi_work(void *data)
+{
+ struct ibmvscsi_host_data *hostdata = data;
+ int rc;
+
+ set_user_nice(current, -20);
+
+ while (1) {
+ rc = wait_event_interruptible(hostdata->work_wait_q,
+ ibmvscsi_work_to_do(hostdata));
+
+ BUG_ON(rc);
+
+ if (kthread_should_stop())
+ break;
+
+ ibmvscsi_do_work(hostdata);
+ }
+
+ return 0;
+}
+
/**
* Called by bus code for each adapter
*/
@@ -1875,6 +1923,7 @@ static int ibmvscsi_probe(struct vio_dev
hostdata = shost_priv(host);
memset(hostdata, 0x00, sizeof(*hostdata));
INIT_LIST_HEAD(&hostdata->sent);
+ init_waitqueue_head(&hostdata->work_wait_q);
hostdata->host = host;
hostdata->dev = dev;
atomic_set(&hostdata->request_limit, -1);
@@ -1885,10 +1934,19 @@ static int ibmvscsi_probe(struct vio_dev
goto persist_bufs_failed;
}
+ hostdata->work_thread = kthread_run(ibmvscsi_work, hostdata, "%s_%d",
+ "ibmvscsi", host->host_no);
+
+ if (IS_ERR(hostdata->work_thread)) {
+ dev_err(&vdev->dev, "couldn't initialize kthread. rc=%ld\n",
+ PTR_ERR(hostdata->work_thread));
+ goto init_crq_failed;
+ }
+
rc = ibmvscsi_ops->init_crq_queue(&hostdata->queue, hostdata, max_events);
if (rc != 0 && rc != H_RESOURCE) {
dev_err(&vdev->dev, "couldn't initialize crq. rc=%d\n", rc);
- goto init_crq_failed;
+ goto kill_kthread;
}
if (initialize_event_pool(&hostdata->pool, max_events, hostdata) != 0) {
dev_err(&vdev->dev, "couldn't initialize event pool\n");
@@ -1944,6 +2002,8 @@ static int ibmvscsi_probe(struct vio_dev
release_event_pool(&hostdata->pool, hostdata);
init_pool_failed:
ibmvscsi_ops->release_crq_queue(&hostdata->queue, hostdata, max_events);
+ kill_kthread:
+ kthread_stop(hostdata->work_thread);
init_crq_failed:
unmap_persist_bufs(hostdata);
persist_bufs_failed:
@@ -1960,6 +2020,7 @@ static int ibmvscsi_remove(struct vio_de
ibmvscsi_ops->release_crq_queue(&hostdata->queue, hostdata,
max_events);
+ kthread_stop(hostdata->work_thread);
srp_remove_host(hostdata->host);
scsi_remove_host(hostdata->host);
scsi_host_put(hostdata->host);
diff -puN drivers/scsi/ibmvscsi/rpa_vscsi.c~ibmvscsi_reenable_sleep drivers/scsi/ibmvscsi/rpa_vscsi.c
--- linux-2.6/drivers/scsi/ibmvscsi/rpa_vscsi.c~ibmvscsi_reenable_sleep 2010-06-10 12:08:44.000000000 -0500
+++ linux-2.6-bjking1/drivers/scsi/ibmvscsi/rpa_vscsi.c 2010-06-10 12:08:44.000000000 -0500
@@ -31,6 +31,7 @@
#include <asm/prom.h>
#include <asm/iommu.h>
#include <asm/hvcall.h>
+#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/interrupt.h>
@@ -71,11 +72,13 @@ static void rpavscsi_release_crq_queue(s
struct ibmvscsi_host_data *hostdata,
int max_requests)
{
- long rc;
+ long rc = 0;
struct vio_dev *vdev = to_vio_dev(hostdata->dev);
free_irq(vdev->irq, (void *)hostdata);
tasklet_kill(&hostdata->srp_task);
do {
+ if (rc)
+ msleep(100);
rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
dma_unmap_single(hostdata->dev,
@@ -200,11 +203,13 @@ static void set_adapter_info(struct ibmv
static int rpavscsi_reset_crq_queue(struct crq_queue *queue,
struct ibmvscsi_host_data *hostdata)
{
- int rc;
+ int rc = 0;
struct vio_dev *vdev = to_vio_dev(hostdata->dev);
/* Close the CRQ */
do {
+ if (rc)
+ msleep(100);
rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
@@ -300,7 +305,10 @@ static int rpavscsi_init_crq_queue(struc
return retrc;
req_irq_failed:
+ rc = 0;
do {
+ if (rc)
+ msleep(100);
rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
reg_crq_failed:
@@ -322,11 +330,13 @@ static int rpavscsi_init_crq_queue(struc
static int rpavscsi_reenable_crq_queue(struct crq_queue *queue,
struct ibmvscsi_host_data *hostdata)
{
- int rc;
+ int rc = 0;
struct vio_dev *vdev = to_vio_dev(hostdata->dev);
/* Re-enable the CRQ */
do {
+ if (rc)
+ msleep(100);
rc = plpar_hcall_norets(H_ENABLE_CRQ, vdev->unit_address);
} while ((rc == H_IN_PROGRESS) || (rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
_
--
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