Commit c6eb7b77 authored by Horst Hummel's avatar Horst Hummel Committed by Linus Torvalds
Browse files

[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: default avatarHorst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 942eaabd

drivers/s390/block/dasd.c

+6 −13
Original line number Diff line number Diff line
@@ -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 "

drivers/s390/block/dasd_devmap.c

+6 −2
Original line number Diff line number Diff line
@@ -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;

}

drivers/s390/block/dasd_genhd.c

+3 −7
Original line number Diff line number Diff line
@@ -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;

drivers/s390/block/dasd_int.h

+2 −1
Original line number Diff line number Diff line
@@ -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;

drivers/s390/block/dasd_ioctl.c

+5 −12
Original line number Diff line number Diff line
@@ -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);

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