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synced 2024-09-06 10:57:46 +00:00
s390/3270: avoid endless I/O loop with disconnected 3270 terminals
If a 3270 terminal is disconnected while the tty view is active the 3270 driver goes into an endless loop of failed I/O requests until the terminal is connected again. Add code to the raw3270 interrupt handler to check for unit checks due to failed I/O requests and put the device to sleep with the RAW3270_FLAGS_BUSY flag until a unsolicited device end interrupt indicates that the device can be used again. while we are at it simplify the 3270 irq handling and remove unnecessary code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
parent
2e63a3a666
commit
8340ab60b3
5 changed files with 24 additions and 96 deletions
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@ -400,7 +400,7 @@ con3270_deactivate(struct raw3270_view *view)
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del_timer(&cp->timer);
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}
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static int
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static void
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con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb)
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{
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/* Handle ATTN. Schedule tasklet to read aid. */
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@ -418,7 +418,6 @@ con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb)
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cp->update_flags = CON_UPDATE_ALL;
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con3270_set_timer(cp, 1);
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}
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return RAW3270_IO_DONE;
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}
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/* Console view to a 3270 device. */
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@ -217,7 +217,7 @@ fs3270_deactivate(struct raw3270_view *view)
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fp->init->callback(fp->init, NULL);
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}
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static int
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static void
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fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
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{
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/* Handle ATTN. Set indication and wake waiters for attention. */
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@ -233,7 +233,6 @@ fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb)
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/* Normal end. Copy residual count. */
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rq->rescnt = irb->scsw.cmd.count;
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}
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return RAW3270_IO_DONE;
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}
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/*
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@ -228,29 +228,6 @@ raw3270_request_set_idal(struct raw3270_request *rq, struct idal_buffer *ib)
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rq->ccw.flags |= CCW_FLAG_IDA;
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}
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/*
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* Stop running ccw.
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*/
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static int
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__raw3270_halt_io(struct raw3270 *rp, struct raw3270_request *rq)
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{
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int retries;
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int rc;
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if (raw3270_request_final(rq))
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return 0;
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/* Check if interrupt has already been processed */
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for (retries = 0; retries < 5; retries++) {
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if (retries < 2)
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rc = ccw_device_halt(rp->cdev, (long) rq);
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else
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rc = ccw_device_clear(rp->cdev, (long) rq);
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if (rc == 0)
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break; /* termination successful */
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}
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return rc;
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}
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/*
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* Add the request to the request queue, try to start it if the
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* 3270 device is idle. Return without waiting for end of i/o.
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@ -342,7 +319,6 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
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struct raw3270 *rp;
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struct raw3270_view *view;
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struct raw3270_request *rq;
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int rc;
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rp = dev_get_drvdata(&cdev->dev);
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if (!rp)
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@ -350,55 +326,27 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
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rq = (struct raw3270_request *) intparm;
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view = rq ? rq->view : rp->view;
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if (IS_ERR(irb))
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rc = RAW3270_IO_RETRY;
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else if (irb->scsw.cmd.fctl & SCSW_FCTL_HALT_FUNC) {
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rq->rc = -EIO;
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rc = RAW3270_IO_DONE;
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} else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END |
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DEV_STAT_UNIT_EXCEP)) {
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if (!IS_ERR(irb)) {
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/* Handle CE-DE-UE and subsequent UDE */
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set_bit(RAW3270_FLAGS_BUSY, &rp->flags);
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rc = RAW3270_IO_BUSY;
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} else if (test_bit(RAW3270_FLAGS_BUSY, &rp->flags)) {
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/* Wait for UDE if busy flag is set. */
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if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) {
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if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END)
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clear_bit(RAW3270_FLAGS_BUSY, &rp->flags);
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/* Got it, now retry. */
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rc = RAW3270_IO_RETRY;
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} else
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rc = RAW3270_IO_BUSY;
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} else if (view)
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rc = view->fn->intv(view, rq, irb);
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else
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rc = RAW3270_IO_DONE;
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switch (rc) {
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case RAW3270_IO_DONE:
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break;
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case RAW3270_IO_BUSY:
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/*
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* Intervention required by the operator. We have to wait
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* for unsolicited device end.
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*/
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return;
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case RAW3270_IO_RETRY:
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if (!rq)
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break;
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rq->rc = ccw_device_start(rp->cdev, &rq->ccw,
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(unsigned long) rq, 0, 0);
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if (rq->rc == 0)
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return; /* Successfully restarted. */
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break;
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case RAW3270_IO_STOP:
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if (!rq)
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break;
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__raw3270_halt_io(rp, rq);
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rq->rc = -EIO;
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break;
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default:
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BUG();
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if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END |
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DEV_STAT_DEV_END |
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DEV_STAT_UNIT_EXCEP))
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set_bit(RAW3270_FLAGS_BUSY, &rp->flags);
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/* Handle disconnected devices */
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if ((irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) &&
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(irb->ecw[0] & SNS0_INTERVENTION_REQ))
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set_bit(RAW3270_FLAGS_BUSY, &rp->flags);
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/* Call interrupt handler of the view */
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if (view)
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view->fn->intv(view, rq, irb);
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}
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if (test_bit(RAW3270_FLAGS_BUSY, &rp->flags))
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/* Device busy, do not start I/O */
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return;
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if (rq) {
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BUG_ON(list_empty(&rq->list));
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/* The request completed, remove from queue and do callback. */
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@ -408,6 +356,7 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
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/* Do put_device for get_device in raw3270_start. */
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raw3270_put_view(view);
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}
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/*
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* Try to start each request on request queue until one is
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* started successful.
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@ -685,23 +634,12 @@ raw3270_reset(struct raw3270_view *view)
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return rc;
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}
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static int
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static void
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raw3270_init_irq(struct raw3270_view *view, struct raw3270_request *rq,
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struct irb *irb)
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{
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struct raw3270 *rp;
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/*
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* Unit-Check Processing:
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* Expect Command Reject or Intervention Required.
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*/
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if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) {
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/* Request finished abnormally. */
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if (irb->ecw[0] & SNS0_INTERVENTION_REQ) {
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set_bit(RAW3270_FLAGS_BUSY, &view->dev->flags);
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return RAW3270_IO_BUSY;
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}
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}
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if (rq) {
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if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) {
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if (irb->ecw[0] & SNS0_CMD_REJECT)
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@ -715,7 +653,6 @@ raw3270_init_irq(struct raw3270_view *view, struct raw3270_request *rq,
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rp = view->dev;
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raw3270_read_modified(rp);
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}
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return RAW3270_IO_DONE;
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}
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static struct raw3270_fn raw3270_init_fn = {
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@ -125,19 +125,13 @@ raw3270_request_final(struct raw3270_request *rq)
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void raw3270_buffer_address(struct raw3270 *, char *, unsigned short);
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/* Return value of *intv (see raw3270_fn below) can be one of the following: */
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#define RAW3270_IO_DONE 0 /* request finished */
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#define RAW3270_IO_BUSY 1 /* request still active */
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#define RAW3270_IO_RETRY 2 /* retry current request */
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#define RAW3270_IO_STOP 3 /* kill current request */
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/*
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* Functions of a 3270 view.
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*/
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struct raw3270_fn {
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int (*activate)(struct raw3270_view *);
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void (*deactivate)(struct raw3270_view *);
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int (*intv)(struct raw3270_view *,
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void (*intv)(struct raw3270_view *,
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struct raw3270_request *, struct irb *);
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void (*release)(struct raw3270_view *);
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void (*free)(struct raw3270_view *);
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@ -645,7 +645,7 @@ tty3270_deactivate(struct raw3270_view *view)
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del_timer(&tp->timer);
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}
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static int
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static void
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tty3270_irq(struct tty3270 *tp, struct raw3270_request *rq, struct irb *irb)
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{
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/* Handle ATTN. Schedule tasklet to read aid. */
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@ -667,7 +667,6 @@ tty3270_irq(struct tty3270 *tp, struct raw3270_request *rq, struct irb *irb)
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tp->update_flags = TTY_UPDATE_ALL;
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tty3270_set_timer(tp, 1);
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}
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return RAW3270_IO_DONE;
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}
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/*
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