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authorStefan Haberland <stefan.haberland@de.ibm.com>2010-02-27 00:37:46 +0300
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-02-27 00:37:32 +0300
commit9eb251225ab4dbea3119cfcf4c5194eed223a740 (patch)
tree6305782cf36aee2949b7a6d1661db24ef618e2ce /drivers/s390/block
parent22e0a0467292222214d1974d9bc2664a6c05980d (diff)
downloadlinux-9eb251225ab4dbea3119cfcf4c5194eed223a740.tar.xz
[S390] dasd: fix online/offline race
Setting a DASD online and offline in quick succession may cause a kernel panic or let the chhccwdev command wait forever. The Online process is split into two parts. After the first part is finished the offline process may be called. This may result in a situation where the second online processing part tries to set the DASD offline as well. Use a mutex to protect online and offline against each other. Also correct some checking. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/block')
-rw-r--r--drivers/s390/block/dasd.c22
-rw-r--r--drivers/s390/block/dasd_genhd.c1
-rw-r--r--drivers/s390/block/dasd_int.h1
3 files changed, 16 insertions, 8 deletions
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 5905936c7c60..56df3c5ed385 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -20,6 +20,7 @@
#include <linux/buffer_head.h>
#include <linux/hdreg.h>
#include <linux/async.h>
+#include <linux/mutex.h>
#include <asm/ccwdev.h>
#include <asm/ebcdic.h>
@@ -112,6 +113,7 @@ struct dasd_device *dasd_alloc_device(void)
INIT_WORK(&device->restore_device, do_restore_device);
device->state = DASD_STATE_NEW;
device->target = DASD_STATE_NEW;
+ mutex_init(&device->state_mutex);
return device;
}
@@ -484,10 +486,8 @@ static void dasd_change_state(struct dasd_device *device)
if (rc)
device->target = device->state;
- if (device->state == device->target) {
+ if (device->state == device->target)
wake_up(&dasd_init_waitq);
- dasd_put_device(device);
- }
/* let user-space know that the device status changed */
kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
@@ -502,7 +502,9 @@ static void dasd_change_state(struct dasd_device *device)
static void do_kick_device(struct work_struct *work)
{
struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
+ mutex_lock(&device->state_mutex);
dasd_change_state(device);
+ mutex_unlock(&device->state_mutex);
dasd_schedule_device_bh(device);
dasd_put_device(device);
}
@@ -539,18 +541,19 @@ void dasd_restore_device(struct dasd_device *device)
void dasd_set_target_state(struct dasd_device *device, int target)
{
dasd_get_device(device);
+ mutex_lock(&device->state_mutex);
/* If we are in probeonly mode stop at DASD_STATE_READY. */
if (dasd_probeonly && target > DASD_STATE_READY)
target = DASD_STATE_READY;
if (device->target != target) {
- if (device->state == target) {
+ if (device->state == target)
wake_up(&dasd_init_waitq);
- dasd_put_device(device);
- }
device->target = target;
}
if (device->state != device->target)
dasd_change_state(device);
+ mutex_unlock(&device->state_mutex);
+ dasd_put_device(device);
}
/*
@@ -1692,7 +1695,6 @@ int dasd_cancel_req(struct dasd_ccw_req *cqr)
cqr, rc);
} else {
cqr->stopclk = get_clock();
- rc = 1;
}
break;
default: /* already finished or clear pending - do nothing */
@@ -2170,9 +2172,13 @@ static void dasd_flush_request_queue(struct dasd_block *block)
static int dasd_open(struct block_device *bdev, fmode_t mode)
{
struct dasd_block *block = bdev->bd_disk->private_data;
- struct dasd_device *base = block->base;
+ struct dasd_device *base;
int rc;
+ if (!block)
+ return -ENODEV;
+
+ base = block->base;
atomic_inc(&block->open_count);
if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
rc = -ENODEV;
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index d3198303b93c..94f92a1247f2 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -88,6 +88,7 @@ void dasd_gendisk_free(struct dasd_block *block)
if (block->gdp) {
del_gendisk(block->gdp);
block->gdp->queue = NULL;
+ block->gdp->private_data = NULL;
put_disk(block->gdp);
block->gdp = NULL;
}
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index e4c2143dabf6..ed73ce550822 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -368,6 +368,7 @@ struct dasd_device {
/* Device state and target state. */
int state, target;
+ struct mutex state_mutex;
int stopped; /* device (ccw_device_start) was stopped */
/* reference count. */