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[PATCH] s390: deadlock in dasd_devmap 

Reintroduce a read-only copy of the devmap features in the device struct.
This is necessary to solve a deadlock on the dasd_devmap_lock which is
acquired by dasd_get_features called from the dasd tasklet.  The current
implementation of devmap doesn't allow to call any devmap function from
interrupt or softirq context.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Horst Hummel 2005-09-03 15:57:58 -07:00 committed by Linus Torvalds
parent 942eaabd5d
commit c6eb7b7703
6 changed files with 24 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/s390/block/dasd.c
View File

@ -7,7 +7,7 @@
* Bugreports.to..: <Linux390@de.ibm.com>
* (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
*
* $Revision: 1.165 $
* $Revision: 1.167 $
*/
#include <linux/config.h>
@ -1131,17 +1131,13 @@ __dasd_process_blk_queue(struct dasd_device * device)
request_queue_t *queue;
struct request *req;
struct dasd_ccw_req *cqr;
int nr_queued, feature_ro;
int nr_queued;
queue = device->request_queue;
/* No queue ? Then there is nothing to do. */
if (queue == NULL)
return;
feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
if (feature_ro < 0) /* no devmap */
return;
/*
* We requeue request from the block device queue to the ccw
* queue only in two states. In state DASD_STATE_READY the
@ -1162,7 +1158,8 @@ __dasd_process_blk_queue(struct dasd_device * device)
nr_queued < DASD_CHANQ_MAX_SIZE) {
req = elv_next_request(queue);
if (feature_ro && rq_data_dir(req) == WRITE) {
if (device->features & DASD_FEATURE_READONLY &&
rq_data_dir(req) == WRITE) {
DBF_DEV_EVENT(DBF_ERR, device,
"Rejecting write request %p",
req);
@ -1814,17 +1811,13 @@ dasd_generic_set_online (struct ccw_device *cdev,
{
struct dasd_device *device;
int feature_diag, rc;
int rc;
device = dasd_create_device(cdev);
if (IS_ERR(device))
return PTR_ERR(device);
feature_diag = dasd_get_feature(cdev, DASD_FEATURE_USEDIAG);
if (feature_diag < 0)
return feature_diag;
if (feature_diag) {
if (device->features & DASD_FEATURE_USEDIAG) {
if (!dasd_diag_discipline_pointer) {
printk (KERN_WARNING
"dasd_generic couldn't online device %s "

8
drivers/s390/block/dasd_devmap.c
View File

@ -11,7 +11,7 @@
* functions may not be called from interrupt context. In particular
* dasd_get_device is a no-no from interrupt context.
*
* $Revision: 1.40 $
* $Revision: 1.43 $
*/
#include <linux/config.h>
@ -513,6 +513,7 @@ dasd_create_device(struct ccw_device *cdev)
if (!devmap->device) {
devmap->device = device;
device->devindex = devmap->devindex;
device->features = devmap->features;
get_device(&cdev->dev);
device->cdev = cdev;
rc = 0;
@ -643,6 +644,8 @@ dasd_ro_store(struct device *dev, struct device_attribute *attr, const char *buf
devmap->features |= DASD_FEATURE_READONLY;
else
devmap->features &= ~DASD_FEATURE_READONLY;
if (devmap->device)
devmap->device->features = devmap->features;
if (devmap->device && devmap->device->gdp)
set_disk_ro(devmap->device->gdp, ro_flag);
spin_unlock(&dasd_devmap_lock);
@ -758,7 +761,8 @@ dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
devmap->features |= feature;
else
devmap->features &= ~feature;
if (devmap->device)
devmap->device->features = devmap->features;
spin_unlock(&dasd_devmap_lock);
return 0;
}

10
drivers/s390/block/dasd_genhd.c
View File

@ -9,7 +9,7 @@
*
* gendisk related functions for the dasd driver.
*
* $Revision: 1.50 $
* $Revision: 1.51 $
*/
#include <linux/config.h>
@ -31,16 +31,12 @@ int
dasd_gendisk_alloc(struct dasd_device *device)
{
struct gendisk *gdp;
int len, feature_ro;
int len;
/* Make sure the minor for this device exists. */
if (device->devindex >= DASD_PER_MAJOR)
return -EBUSY;
feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
if (feature_ro < 0)
return feature_ro;
gdp = alloc_disk(1 << DASD_PARTN_BITS);
if (!gdp)
return -ENOMEM;
@ -75,7 +71,7 @@ dasd_gendisk_alloc(struct dasd_device *device)
sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
if (feature_ro)
if (device->features & DASD_FEATURE_READONLY)
set_disk_ro(gdp, 1);
gdp->private_data = device;
gdp->queue = device->request_queue;

3
drivers/s390/block/dasd_int.h
View File

@ -6,7 +6,7 @@
* Bugreports.to..: <Linux390@de.ibm.com>
* (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
*
* $Revision: 1.64 $
* $Revision: 1.65 $
*/
#ifndef DASD_INT_H
@ -286,6 +286,7 @@ struct dasd_device {
unsigned int bp_block; /* bytes per block */
unsigned int s2b_shift; /* log2 (bp_block/512) */
unsigned long flags; /* per device flags */
unsigned short features; /* copy of devmap-features (read-only!) */
/* Device discipline stuff. */
struct dasd_discipline *discipline;

17
drivers/s390/block/dasd_ioctl.c
View File

@ -7,7 +7,7 @@
* Bugreports.to..: <Linux390@de.ibm.com>
* (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
*
* $Revision: 1.45 $
* $Revision: 1.47 $
*
* i/o controls for the dasd driver.
*/
@ -296,7 +296,6 @@ dasd_ioctl_format(struct block_device *bdev, int no, long args)
{
struct dasd_device *device;
struct format_data_t fdata;
int feature_ro;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
@ -308,10 +307,7 @@ dasd_ioctl_format(struct block_device *bdev, int no, long args)
if (device == NULL)
return -ENODEV;
feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
if (feature_ro < 0)
return feature_ro;
if (feature_ro)
if (device->features & DASD_FEATURE_READONLY)
return -EROFS;
if (copy_from_user(&fdata, (void __user *) args,
sizeof (struct format_data_t)))
@ -384,7 +380,7 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
struct dasd_device *device;
struct dasd_information2_t *dasd_info;
unsigned long flags;
int rc, feature_ro;
int rc;
struct ccw_device *cdev;
device = bdev->bd_disk->private_data;
@ -394,10 +390,6 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
if (!device->discipline->fill_info)
return -EINVAL;
feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
if (feature_ro < 0)
return feature_ro;
dasd_info = kmalloc(sizeof(struct dasd_information2_t), GFP_KERNEL);
if (dasd_info == NULL)
return -ENOMEM;
@ -427,7 +419,8 @@ dasd_ioctl_information(struct block_device *bdev, int no, long args)
(dasd_check_blocksize(device->bp_block)))
dasd_info->format = DASD_FORMAT_NONE;
dasd_info->features |= feature_ro;
dasd_info->features |=
((device->features & DASD_FEATURE_READONLY) != 0);
if (device->discipline)
memcpy(dasd_info->type, device->discipline->name, 4);

8
drivers/s390/block/dasd_proc.c
View File

@ -9,7 +9,7 @@
*
* /proc interface for the dasd driver.
*
* $Revision: 1.32 $
* $Revision: 1.33 $
*/
#include <linux/config.h>
@ -55,7 +55,6 @@ dasd_devices_show(struct seq_file *m, void *v)
{
struct dasd_device *device;
char *substr;
int feature;
device = dasd_device_from_devindex((unsigned long) v - 1);
if (IS_ERR(device))
@ -79,10 +78,7 @@ dasd_devices_show(struct seq_file *m, void *v)
else
seq_printf(m, " is ????????");
/* Print devices features. */
feature = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
if (feature < 0)
return 0;
substr = feature ? "(ro)" : " ";
substr = (device->features & DASD_FEATURE_READONLY) ? "(ro)" : " ";
seq_printf(m, "%4s: ", substr);
/* Print device status information. */
switch ((device != NULL) ? device->state : -1) {