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| author | Stefan Haberland <stefan.haberland@de.ibm.com> | 2009-10-06 10:34:15 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2009-10-06 10:35:11 +0200 |
| commit | 6fca97a958bc3c67566aa91eafc6a5be2e66d6b3 (patch) | |
| tree | 9e5ca7c9c3d14c45f469feb58cab15212cee9d6b /drivers | |
| parent | [S390] Add EX_TABLE for addressing exception in usercopy functions. (diff) | |
| download | linux-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')
| -rw-r--r-- | drivers/s390/block/dasd.c | 5 | ||||
| -rw-r--r-- | drivers/s390/block/dasd_eckd.c | 9 |
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); |