From 8340ab60b3624386eaa24fa21bdb4e6775066ccf Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 2 May 2016 14:53:29 +0200 Subject: 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 --- drivers/s390/char/con3270.c | 3 +- drivers/s390/char/fs3270.c | 3 +- drivers/s390/char/raw3270.c | 101 +++++++++----------------------------------- drivers/s390/char/raw3270.h | 8 +--- drivers/s390/char/tty3270.c | 3 +- 5 files changed, 23 insertions(+), 95 deletions(-) (limited to 'drivers') diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c index 4d7a9badfede..6b1577c73fe7 100644 --- a/drivers/s390/char/con3270.c +++ b/drivers/s390/char/con3270.c @@ -400,7 +400,7 @@ con3270_deactivate(struct raw3270_view *view) del_timer(&cp->timer); } -static int +static void con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb) { /* Handle ATTN. Schedule tasklet to read aid. */ @@ -418,7 +418,6 @@ con3270_irq(struct con3270 *cp, struct raw3270_request *rq, struct irb *irb) cp->update_flags = CON_UPDATE_ALL; con3270_set_timer(cp, 1); } - return RAW3270_IO_DONE; } /* Console view to a 3270 device. */ diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c index 71e974738014..85eca1cef063 100644 --- a/drivers/s390/char/fs3270.c +++ b/drivers/s390/char/fs3270.c @@ -217,7 +217,7 @@ fs3270_deactivate(struct raw3270_view *view) fp->init->callback(fp->init, NULL); } -static int +static void fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb) { /* Handle ATTN. Set indication and wake waiters for attention. */ @@ -233,7 +233,6 @@ fs3270_irq(struct fs3270 *fp, struct raw3270_request *rq, struct irb *irb) /* Normal end. Copy residual count. */ rq->rescnt = irb->scsw.cmd.count; } - return RAW3270_IO_DONE; } /* diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c index 220acb4cbee5..0743f13101ee 100644 --- a/drivers/s390/char/raw3270.c +++ b/drivers/s390/char/raw3270.c @@ -228,29 +228,6 @@ raw3270_request_set_idal(struct raw3270_request *rq, struct idal_buffer *ib) rq->ccw.flags |= CCW_FLAG_IDA; } -/* - * Stop running ccw. - */ -static int -__raw3270_halt_io(struct raw3270 *rp, struct raw3270_request *rq) -{ - int retries; - int rc; - - if (raw3270_request_final(rq)) - return 0; - /* Check if interrupt has already been processed */ - for (retries = 0; retries < 5; retries++) { - if (retries < 2) - rc = ccw_device_halt(rp->cdev, (long) rq); - else - rc = ccw_device_clear(rp->cdev, (long) rq); - if (rc == 0) - break; /* termination successful */ - } - return rc; -} - /* * Add the request to the request queue, try to start it if the * 3270 device is idle. Return without waiting for end of i/o. @@ -342,7 +319,6 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb) struct raw3270 *rp; struct raw3270_view *view; struct raw3270_request *rq; - int rc; rp = dev_get_drvdata(&cdev->dev); if (!rp) @@ -350,55 +326,27 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb) rq = (struct raw3270_request *) intparm; view = rq ? rq->view : rp->view; - if (IS_ERR(irb)) - rc = RAW3270_IO_RETRY; - else if (irb->scsw.cmd.fctl & SCSW_FCTL_HALT_FUNC) { - rq->rc = -EIO; - rc = RAW3270_IO_DONE; - } else if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END | - DEV_STAT_UNIT_EXCEP)) { + if (!IS_ERR(irb)) { /* Handle CE-DE-UE and subsequent UDE */ - set_bit(RAW3270_FLAGS_BUSY, &rp->flags); - rc = RAW3270_IO_BUSY; - } else if (test_bit(RAW3270_FLAGS_BUSY, &rp->flags)) { - /* Wait for UDE if busy flag is set. */ - if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) { + if (irb->scsw.cmd.dstat & DEV_STAT_DEV_END) clear_bit(RAW3270_FLAGS_BUSY, &rp->flags); - /* Got it, now retry. */ - rc = RAW3270_IO_RETRY; - } else - rc = RAW3270_IO_BUSY; - } else if (view) - rc = view->fn->intv(view, rq, irb); - else - rc = RAW3270_IO_DONE; + if (irb->scsw.cmd.dstat == (DEV_STAT_CHN_END | + DEV_STAT_DEV_END | + DEV_STAT_UNIT_EXCEP)) + set_bit(RAW3270_FLAGS_BUSY, &rp->flags); + /* Handle disconnected devices */ + if ((irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) && + (irb->ecw[0] & SNS0_INTERVENTION_REQ)) + set_bit(RAW3270_FLAGS_BUSY, &rp->flags); + /* Call interrupt handler of the view */ + if (view) + view->fn->intv(view, rq, irb); + } - switch (rc) { - case RAW3270_IO_DONE: - break; - case RAW3270_IO_BUSY: - /* - * Intervention required by the operator. We have to wait - * for unsolicited device end. - */ + if (test_bit(RAW3270_FLAGS_BUSY, &rp->flags)) + /* Device busy, do not start I/O */ return; - case RAW3270_IO_RETRY: - if (!rq) - break; - rq->rc = ccw_device_start(rp->cdev, &rq->ccw, - (unsigned long) rq, 0, 0); - if (rq->rc == 0) - return; /* Successfully restarted. */ - break; - case RAW3270_IO_STOP: - if (!rq) - break; - __raw3270_halt_io(rp, rq); - rq->rc = -EIO; - break; - default: - BUG(); - } + if (rq) { BUG_ON(list_empty(&rq->list)); /* The request completed, remove from queue and do callback. */ @@ -408,6 +356,7 @@ raw3270_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb) /* Do put_device for get_device in raw3270_start. */ raw3270_put_view(view); } + /* * Try to start each request on request queue until one is * started successful. @@ -685,23 +634,12 @@ raw3270_reset(struct raw3270_view *view) return rc; } -static int +static void raw3270_init_irq(struct raw3270_view *view, struct raw3270_request *rq, struct irb *irb) { struct raw3270 *rp; - /* - * Unit-Check Processing: - * Expect Command Reject or Intervention Required. - */ - if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) { - /* Request finished abnormally. */ - if (irb->ecw[0] & SNS0_INTERVENTION_REQ) { - set_bit(RAW3270_FLAGS_BUSY, &view->dev->flags); - return RAW3270_IO_BUSY; - } - } if (rq) { if (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) { if (irb->ecw[0] & SNS0_CMD_REJECT) @@ -715,7 +653,6 @@ raw3270_init_irq(struct raw3270_view *view, struct raw3270_request *rq, rp = view->dev; raw3270_read_modified(rp); } - return RAW3270_IO_DONE; } static struct raw3270_fn raw3270_init_fn = { diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h index e1e41c2861fb..56519cbb165c 100644 --- a/drivers/s390/char/raw3270.h +++ b/drivers/s390/char/raw3270.h @@ -125,19 +125,13 @@ raw3270_request_final(struct raw3270_request *rq) void raw3270_buffer_address(struct raw3270 *, char *, unsigned short); -/* Return value of *intv (see raw3270_fn below) can be one of the following: */ -#define RAW3270_IO_DONE 0 /* request finished */ -#define RAW3270_IO_BUSY 1 /* request still active */ -#define RAW3270_IO_RETRY 2 /* retry current request */ -#define RAW3270_IO_STOP 3 /* kill current request */ - /* * Functions of a 3270 view. */ struct raw3270_fn { int (*activate)(struct raw3270_view *); void (*deactivate)(struct raw3270_view *); - int (*intv)(struct raw3270_view *, + void (*intv)(struct raw3270_view *, struct raw3270_request *, struct irb *); void (*release)(struct raw3270_view *); void (*free)(struct raw3270_view *); diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c index 54ea5a01e30d..d6da18612ba8 100644 --- a/drivers/s390/char/tty3270.c +++ b/drivers/s390/char/tty3270.c @@ -645,7 +645,7 @@ tty3270_deactivate(struct raw3270_view *view) del_timer(&tp->timer); } -static int +static void tty3270_irq(struct tty3270 *tp, struct raw3270_request *rq, struct irb *irb) { /* Handle ATTN. Schedule tasklet to read aid. */ @@ -667,7 +667,6 @@ tty3270_irq(struct tty3270 *tp, struct raw3270_request *rq, struct irb *irb) tp->update_flags = TTY_UPDATE_ALL; tty3270_set_timer(tp, 1); } - return RAW3270_IO_DONE; } /* -- cgit v1.2.3