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authorStefan Haberland <stefan.haberland@de.ibm.com>2009-10-06 10:34:15 +0200
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2009-10-06 10:35:11 +0200
commit6fca97a958bc3c67566aa91eafc6a5be2e66d6b3 (patch)
tree9e5ca7c9c3d14c45f469feb58cab15212cee9d6b /drivers/s390/block
parent[S390] Add EX_TABLE for addressing exception in usercopy functions. (diff)
downloadlinux-6fca97a958bc3c67566aa91eafc6a5be2e66d6b3.tar.xz
linux-6fca97a958bc3c67566aa91eafc6a5be2e66d6b3.zip
[S390] dasd: fix race condition in resume code
There is a race while re-reading the device characteristics. After cleaning the memory area a cqr is build which reads the device characteristics. This may take a rather long time and the device characteristics structure is zero during this. Now it could be possible that the block tasklet starts working and a new cqr will be build. The build_cp command refers to the device characteristics structure and this may lead into a divide by zero exception. Fix this by re-reading the device characteristics into a temporary structur and copy the data to the original structure. Also take the ccwdev_lock. 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.c5
-rw-r--r--drivers/s390/block/dasd_eckd.c9
2 files changed, 10 insertions, 4 deletions
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index dad0449475b6..53b8c255360a 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2508,8 +2508,6 @@ int dasd_generic_restore_device(struct ccw_device *cdev)
device->stopped &= ~DASD_UNRESUMED_PM;
dasd_schedule_device_bh(device);
- if (device->block)
- dasd_schedule_block_bh(device->block);
if (device->discipline->restore)
rc = device->discipline->restore(device);
@@ -2520,6 +2518,9 @@ int dasd_generic_restore_device(struct ccw_device *cdev)
*/
device->stopped |= DASD_UNRESUMED_PM;
+ if (device->block)
+ dasd_schedule_block_bh(device->block);
+
dasd_put_device(device);
return 0;
}
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index ab3521755588..0be7c15f45c5 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2338,6 +2338,8 @@ static struct dasd_ccw_req *dasd_eckd_build_cp(struct dasd_device *startdev,
/* Calculate number of blocks/records per track. */
blksize = block->bp_block;
blk_per_trk = recs_per_track(&private->rdc_data, 0, blksize);
+ if (blk_per_trk == 0)
+ return ERR_PTR(-EINVAL);
/* Calculate record id of first and last block. */
first_rec = first_trk = blk_rq_pos(req) >> block->s2b_shift;
first_offs = sector_div(first_trk, blk_per_trk);
@@ -3211,6 +3213,7 @@ int dasd_eckd_pm_freeze(struct dasd_device *device)
int dasd_eckd_restore_device(struct dasd_device *device)
{
struct dasd_eckd_private *private;
+ struct dasd_eckd_characteristics temp_rdc_data;
int is_known, rc;
struct dasd_uid temp_uid;
@@ -3245,15 +3248,17 @@ int dasd_eckd_restore_device(struct dasd_device *device)
dasd_eckd_read_features(device);
/* Read Device Characteristics */
- memset(&private->rdc_data, 0, sizeof(private->rdc_data));
rc = dasd_generic_read_dev_chars(device, DASD_ECKD_MAGIC,
- &private->rdc_data, 64);
+ &temp_rdc_data, 64);
if (rc) {
DBF_EVENT(DBF_WARNING,
"Read device characteristics failed, rc=%d for "
"device: %s", rc, dev_name(&device->cdev->dev));
goto out_err;
}
+ spin_lock(get_ccwdev_lock(device->cdev));
+ memcpy(&private->rdc_data, &temp_rdc_data, sizeof(temp_rdc_data));
+ spin_unlock(get_ccwdev_lock(device->cdev));
/* add device to alias management */
dasd_alias_add_device(device);