Commit e1f0fbd6 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Martin Schwidefsky
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[S390] cio: consistent infrastructure for internal I/O requests



Reduce code duplication by introducing a central infrastructure to
perform an internal I/O operation on a CCW device.
Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 16b9a057
......@@ -3,7 +3,7 @@
#
obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o isc.o \
fcx.o itcw.o crw.o
fcx.o itcw.o crw.o ccwreq.o
ccw_device-objs += device.o device_fsm.o device_ops.o
ccw_device-objs += device_id.o device_pgid.o device_status.o
obj-y += ccw_device.o cmf.o
......
/*
* Handling of internal CCW device requests.
*
* Copyright IBM Corp. 2009
* Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
*/
#include <linux/types.h>
#include <linux/err.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
#include "io_sch.h"
#include "cio.h"
#include "device.h"
#include "cio_debug.h"
/**
* lpm_adjust - adjust path mask
* @lpm: path mask to adjust
* @mask: mask of available paths
*
* Shift @lpm right until @lpm and @mask have at least one bit in common or
* until @lpm is zero. Return the resulting lpm.
*/
int lpm_adjust(int lpm, int mask)
{
while (lpm && ((lpm & mask) == 0))
lpm >>= 1;
return lpm;
}
/*
* Adjust path mask to use next path and reset retry count. Return resulting
* path mask.
*/
static u16 ccwreq_next_path(struct ccw_device *cdev)
{
struct ccw_request *req = &cdev->private->req;
req->retries = req->maxretries;
req->mask = lpm_adjust(req->mask >>= 1, req->lpm);
return req->mask;
}
/*
* Clean up device state and report to callback.
*/
static void ccwreq_stop(struct ccw_device *cdev, int rc)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct ccw_request *req = &cdev->private->req;
if (req->done)
return;
req->done = 1;
ccw_device_set_timeout(cdev, 0);
memset(&cdev->private->irb, 0, sizeof(struct irb));
sch->lpm = sch->schib.pmcw.pam;
if (rc && rc != -ENODEV && req->drc)
rc = req->drc;
req->callback(cdev, req->data, rc);
}
/*
* (Re-)Start the operation until retries and paths are exhausted.
*/
static void ccwreq_do(struct ccw_device *cdev)
{
struct ccw_request *req = &cdev->private->req;
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct ccw1 *cp = req->cp;
int rc = -EACCES;
while (req->mask) {
if (req->retries-- == 0) {
/* Retries exhausted, try next path. */
ccwreq_next_path(cdev);
continue;
}
/* Perform start function. */
sch->lpm = 0xff;
memset(&cdev->private->irb, 0, sizeof(struct irb));
rc = cio_start(sch, cp, req->mask);
if (rc == 0) {
/* I/O started successfully. */
ccw_device_set_timeout(cdev, req->timeout);
return;
}
if (rc == -ENODEV) {
/* Permanent device error. */
break;
}
if (rc == -EACCES) {
/* Permant path error. */
ccwreq_next_path(cdev);
continue;
}
/* Temporary improper status. */
rc = cio_clear(sch);
if (rc)
break;
return;
}
ccwreq_stop(cdev, rc);
}
/**
* ccw_request_start - perform I/O request
* @cdev: ccw device
*
* Perform the I/O request specified by cdev->req.
*/
void ccw_request_start(struct ccw_device *cdev)
{
struct ccw_request *req = &cdev->private->req;
req->mask = 0x80;
req->retries = req->maxretries;
req->mask = lpm_adjust(req->mask, req->lpm);
req->drc = 0;
req->done = 0;
req->cancel = 0;
if (!req->mask)
goto out_nopath;
ccwreq_do(cdev);
return;
out_nopath:
ccwreq_stop(cdev, -EACCES);
}
/**
* ccw_request_cancel - cancel running I/O request
* @cdev: ccw device
*
* Cancel the I/O request specified by cdev->req. Return non-zero if request
* has already finished, zero otherwise.
*/
int ccw_request_cancel(struct ccw_device *cdev)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct ccw_request *req = &cdev->private->req;
int rc;
if (req->done)
return 1;
req->cancel = 1;
rc = cio_clear(sch);
if (rc)
ccwreq_stop(cdev, rc);
return 0;
}
/*
* Return the status of the internal I/O started on the specified ccw device.
* Perform BASIC SENSE if required.
*/
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;
/* Perform BASIC SENSE if needed. */
if (ccw_device_accumulate_and_sense(cdev, lcirb))
return IO_RUNNING;
/* Check for halt/clear interrupt. */
if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC))
return IO_KILLED;
/* Check for path error. */
if (scsw->cc == 3 || scsw->pno)
return IO_PATH_ERROR;
/* Handle BASIC SENSE data. */
if (irb->esw.esw0.erw.cons) {
CIO_TRACE_EVENT(2, "sensedata");
CIO_HEX_EVENT(2, &cdev->private->dev_id,
sizeof(struct ccw_dev_id));
CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT);
/* Check for command reject. */
if (irb->ecw[0] & SNS0_CMD_REJECT)
return IO_REJECTED;
/* Assume that unexpected SENSE data implies an error. */
return IO_STATUS_ERROR;
}
/* Check for channel errors. */
if (scsw->cstat != 0)
return IO_STATUS_ERROR;
/* Check for device errors. */
if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
return IO_STATUS_ERROR;
/* Check for final state. */
if (!(scsw->dstat & DEV_STAT_DEV_END))
return IO_RUNNING;
/* Check for other improper status. */
if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS))
return IO_STATUS_ERROR;
return IO_DONE;
}
/*
* Log ccw request status.
*/
static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
{
struct ccw_request *req = &cdev->private->req;
struct {
struct ccw_dev_id dev_id;
u16 retries;
u8 lpm;
u8 status;
} __attribute__ ((packed)) data;
data.dev_id = cdev->private->dev_id;
data.retries = req->retries;
data.lpm = req->mask;
data.status = (u8) status;
CIO_TRACE_EVENT(2, "reqstat");
CIO_HEX_EVENT(2, &data, sizeof(data));
}
/**
* ccw_request_handler - interrupt handler for I/O request procedure.
* @cdev: ccw device
*
* Handle interrupt during I/O request procedure.
*/
void ccw_request_handler(struct ccw_device *cdev)
{
struct ccw_request *req = &cdev->private->req;
struct irb *irb = (struct irb *) __LC_IRB;
enum io_status status;
int rc = -EOPNOTSUPP;
/* Check status of I/O request. */
status = ccwreq_status(cdev, irb);
if (req->filter)
status = req->filter(cdev, req->data, irb, status);
if (status != IO_RUNNING)
ccw_device_set_timeout(cdev, 0);
if (status != IO_DONE && status != IO_RUNNING)
ccwreq_log_status(cdev, status);
switch (status) {
case IO_DONE:
break;
case IO_RUNNING:
return;
case IO_REJECTED:
goto err;
case IO_PATH_ERROR:
goto out_next_path;
case IO_STATUS_ERROR:
goto out_restart;
case IO_KILLED:
/* Check if request was cancelled on purpose. */
if (req->cancel) {
rc = -EIO;
goto err;
}
goto out_restart;
}
/* Check back with request initiator. */
if (!req->check)
goto out;
switch (req->check(cdev, req->data)) {
case 0:
break;
case -EAGAIN:
goto out_restart;
case -EACCES:
goto out_next_path;
default:
goto err;
}
out:
ccwreq_stop(cdev, 0);
return;
out_next_path:
/* Try next path and restart I/O. */
if (!ccwreq_next_path(cdev)) {
rc = -EACCES;
goto err;
}
out_restart:
/* Restart. */
ccwreq_do(cdev);
return;
err:
ccwreq_stop(cdev, rc);
}
/**
* ccw_request_timeout - timeout handler for I/O request procedure
* @cdev: ccw device
*
* Handle timeout during I/O request procedure.
*/
void ccw_request_timeout(struct ccw_device *cdev)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct ccw_request *req = &cdev->private->req;
int rc;
if (!ccwreq_next_path(cdev)) {
/* set the final return code for this request */
req->drc = -ETIME;
}
rc = cio_clear(sch);
if (rc)
goto err;
return;
err:
ccwreq_stop(cdev, rc);
}
/**
* ccw_request_notoper - notoper handler for I/O request procedure
* @cdev: ccw device
*
* Handle timeout during I/O request procedure.
*/
void ccw_request_notoper(struct ccw_device *cdev)
{
ccwreq_stop(cdev, -ENODEV);
}
......@@ -98,6 +98,14 @@ void ccw_device_accumulate_basic_sense(struct ccw_device *, struct irb *);
int ccw_device_accumulate_and_sense(struct ccw_device *, struct irb *);
int ccw_device_do_sense(struct ccw_device *, struct irb *);
/* Function prototype for internal request handling. */
int lpm_adjust(int lpm, int mask);
void ccw_request_start(struct ccw_device *);
int ccw_request_cancel(struct ccw_device *cdev);
void ccw_request_handler(struct ccw_device *cdev);
void ccw_request_timeout(struct ccw_device *cdev);
void ccw_request_notoper(struct ccw_device *cdev);
/* Function prototypes for sense id stuff. */
void ccw_device_sense_id_start(struct ccw_device *);
void ccw_device_sense_id_irq(struct ccw_device *, enum dev_event);
......
#ifndef S390_IO_SCH_H
#define S390_IO_SCH_H
#include <linux/types.h>
#include <asm/schid.h>
#include <asm/ccwdev.h>
#include "css.h"
/*
* command-mode operation request block
......@@ -67,6 +70,52 @@ struct io_subchannel_private {
#define MAX_CIWS 8
/*
* Possible status values for a CCW request's I/O.
*/
enum io_status {
IO_DONE,
IO_RUNNING,
IO_STATUS_ERROR,
IO_PATH_ERROR,
IO_REJECTED,
IO_KILLED
};
/**
* ccw_request - Internal CCW request.
* @cp: channel program to start
* @timeout: maximum allowable time in jiffies between start I/O and interrupt
* @maxretries: number of retries per I/O operation and path
* @lpm: mask of paths to use
* @check: optional callback that determines if results are final
* @filter: optional callback to adjust request status based on IRB data
* @callback: final callback
* @data: user-defined pointer passed to all callbacks
* @mask: current path mask
* @retries: current number of retries
* @drc: delayed return code
* @cancel: non-zero if request was cancelled
* @done: non-zero if request was finished
*/
struct ccw_request {
struct ccw1 *cp;
unsigned long timeout;
u16 maxretries;
u8 lpm;
int (*check)(struct ccw_device *, void *);
enum io_status (*filter)(struct ccw_device *, void *, struct irb *,
enum io_status);
void (*callback)(struct ccw_device *, void *, int);
void *data;
/* These fields are used internally. */
u8 mask;
u16 retries;
int drc;
int cancel:1;
int done:1;
} __attribute__((packed));
/*
* sense-id response buffer layout
*/
......@@ -99,6 +148,7 @@ struct ccw_device_private {
unsigned long registered;
struct ccw_dev_id dev_id; /* device id */
struct subchannel_id schid; /* subchannel number */
struct ccw_request req; /* internal I/O request */
u8 imask; /* lpm mask for SNID/SID/SPGID */
int iretry; /* retry counter SNID/SID/SPGID */
struct {
......
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