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Commit 22825ab7 authored by Stefan Weinhuber's avatar Stefan Weinhuber Committed by Martin Schwidefsky
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[S390] dasd: support DIAG access for read-only devices 



When a DASD device is used with the DIAG discipline, the DIAG
initialization will indicate success or error with a respective
return code. So far we have interpreted a return code of 4 as error,
but it actually means that the initialization was successful, but
the device is read-only. To allow read-only devices to be used with
DIAG we need to accept a return code of 4 as success.

Re-initialization of the DIAG access is also part of the DIAG error
recovery. If we find that the access mode of a device has been
changed from writable to read-only while the device was in use,
we print an error message.

Signed-off-by: default avatarStefan Weinhuber <wein@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 6c1e3e79

drivers/s390/block/dasd_diag.c

+16 −3
Original line number Diff line number Diff line
@@ -145,6 +145,15 @@ dasd_diag_erp(struct dasd_device *device) 


	mdsk_term_io(device);

	rc = mdsk_init_io(device, device->block->bp_block, 0, NULL);

	if (rc == 4) {

		if (!(device->features & DASD_FEATURE_READONLY)) {

			dev_warn(&device->cdev->dev,

				 "The access mode of a DIAG device changed"

				 " to read-only");

			device->features |= DASD_FEATURE_READONLY;

		}

		rc = 0;

	}

	if (rc)

		dev_warn(&device->cdev->dev, "DIAG ERP failed with "

			    "rc=%d\n", rc);
@@ -433,16 +442,20 @@ dasd_diag_check_device(struct dasd_device *device) 
	for (sb = 512; sb < bsize; sb = sb << 1)

		block->s2b_shift++;

	rc = mdsk_init_io(device, block->bp_block, 0, NULL);

	if (rc) {

	if (rc && (rc != 4)) {

		dev_warn(&device->cdev->dev, "DIAG initialization "

			"failed with rc=%d\n", rc);

		rc = -EIO;

	} else {

		if (rc == 4)

			device->features |= DASD_FEATURE_READONLY;

		dev_info(&device->cdev->dev,

			 "New DASD with %ld byte/block, total size %ld KB\n",

			 "New DASD with %ld byte/block, total size %ld KB%s\n",

			 (unsigned long) block->bp_block,

			 (unsigned long) (block->blocks <<

					  block->s2b_shift) >> 1);

					  block->s2b_shift) >> 1,

			 (rc == 4) ? ", read-only device" : "");

		rc = 0;

	}

out_label:

	free_page((long) label);