Commit 094f2100 authored by Michael Ernst's avatar Michael Ernst Committed by Martin Schwidefsky
Browse files

[S390] cio: unit check handling during internal I/O 



Send unit checks that occur during internal I/O to the device driver
and react according to its return code.

Signed-off-by: default avatarMichael Ernst <mernst@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent c560d105

arch/s390/include/asm/ccwdev.h

+10 −0
Original line number Diff line number Diff line
@@ -91,6 +91,14 @@ struct ccw_device { 
	void (*handler) (struct ccw_device *, unsigned long, struct irb *);

};



/*

 * Possible CIO actions triggered by the unit check handler.

 */

enum uc_todo {

	UC_TODO_RETRY,

	UC_TODO_RETRY_ON_NEW_PATH,

	UC_TODO_STOP

};



/**

 * struct ccw driver - device driver for channel attached devices
@@ -107,6 +115,7 @@ struct ccw_device { 
 * @freeze: callback for freezing during hibernation snapshotting

 * @thaw: undo work done in @freeze

 * @restore: callback for restoring after hibernation

 * @uc_handler: callback for unit check handler

 * @driver: embedded device driver structure

 * @name: device driver name

 */
@@ -124,6 +133,7 @@ struct ccw_driver { 
	int (*freeze)(struct ccw_device *);

	int (*thaw) (struct ccw_device *);

	int (*restore)(struct ccw_device *);

	enum uc_todo (*uc_handler) (struct ccw_device *, struct irb *);

	struct device_driver driver;

	char *name;

};

drivers/s390/cio/ccwreq.c

+15 −0
Original line number Diff line number Diff line
@@ -159,6 +159,7 @@ static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb) 
{

	struct irb *irb = &cdev->private->irb;

	struct cmd_scsw *scsw = &irb->scsw.cmd;

	enum uc_todo todo;



	/* Perform BASIC SENSE if needed. */

	if (ccw_device_accumulate_and_sense(cdev, lcirb))
@@ -178,6 +179,20 @@ static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb) 
		/* Check for command reject. */

		if (irb->ecw[0] & SNS0_CMD_REJECT)

			return IO_REJECTED;

		/* Ask the driver what to do */

		if (cdev->drv && cdev->drv->uc_handler) {

			todo = cdev->drv->uc_handler(cdev, lcirb);

			switch (todo) {

			case UC_TODO_RETRY:

				return IO_STATUS_ERROR;

			case UC_TODO_RETRY_ON_NEW_PATH:

				return IO_PATH_ERROR;

			case UC_TODO_STOP:

				return IO_REJECTED;

			default:

				return IO_STATUS_ERROR;

			}

		}

		/* Assume that unexpected SENSE data implies an error. */

		return IO_STATUS_ERROR;

	}