[SCSI] ibmvscsi: Fix softlockup on resume
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@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index aad35cc..e50fad9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -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 @@
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 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
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);