From 408aec3c6c3cb5b4774f96ea7a35cd15ee91a56f Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 10 Oct 2008 21:33:28 +0200 Subject: [PATCH] [S390] 3215: Remove tasklet. The 3215 console irq handler used to schedule a tasklet. However the console irq handler also gets called from the infamous cio_tpi() function. Which in turn does something like local_bh_disable() [call console irq handler] _local_bh_enable() _local_bh_enable() prevents execution of softirqs, which is intended within cio_tpi(). However there might be a new softirq pending because irq handler scheduled a tasklet. In order to prevent this behaviour we just get rid of the tasklet. It's not doing much anyway. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- drivers/s390/char/con3215.c | 26 ++++++-------------------- 1 file changed, 6 insertions(+), 20 deletions(-) diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c index 982cf62..9ab06e0 100644 --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -89,7 +89,6 @@ struct raw3215_info { int count; /* number of bytes in output buffer */ int written; /* number of bytes in write requests */ struct tty_struct *tty; /* pointer to tty structure if present */ - struct tasklet_struct tasklet; struct raw3215_req *queued_read; /* pointer to queued read requests */ struct raw3215_req *queued_write;/* pointer to queued write requests */ wait_queue_head_t empty_wait; /* wait queue for flushing */ @@ -342,21 +341,14 @@ raw3215_try_io(struct raw3215_info *raw) } /* - * The bottom half handler routine for 3215 devices. It tries to start - * the next IO and wakes up processes waiting on the tty. + * Try to start the next IO and wake up processes waiting on the tty. */ -static void -raw3215_tasklet(void *data) +static void raw3215_next_io(struct raw3215_info *raw) { - struct raw3215_info *raw; struct tty_struct *tty; - unsigned long flags; - raw = (struct raw3215_info *) data; - spin_lock_irqsave(get_ccwdev_lock(raw->cdev), flags); raw3215_mk_write_req(raw); raw3215_try_io(raw); - spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); tty = raw->tty; if (tty != NULL && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE) { @@ -381,7 +373,7 @@ raw3215_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb) cstat = irb->scsw.cmd.cstat; dstat = irb->scsw.cmd.dstat; if (cstat != 0) - tasklet_schedule(&raw->tasklet); + raw3215_next_io(raw); if (dstat & 0x01) { /* we got a unit exception */ dstat &= ~0x01; /* we can ignore it */ } @@ -391,7 +383,7 @@ raw3215_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb) break; /* Attention interrupt, someone hit the enter key */ raw3215_mk_read_req(raw); - tasklet_schedule(&raw->tasklet); + raw3215_next_io(raw); break; case 0x08: case 0x0C: @@ -449,7 +441,7 @@ raw3215_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb) raw->queued_read == NULL) { wake_up_interruptible(&raw->empty_wait); } - tasklet_schedule(&raw->tasklet); + raw3215_next_io(raw); break; default: /* Strange interrupt, I'll do my best to clean up */ @@ -461,7 +453,7 @@ raw3215_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb) raw->flags &= ~RAW3215_WORKING; raw3215_free_req(req); } - tasklet_schedule(&raw->tasklet); + raw3215_next_io(raw); } return; } @@ -675,9 +667,6 @@ raw3215_probe (struct ccw_device *cdev) kfree(raw); return -ENOMEM; } - tasklet_init(&raw->tasklet, - (void (*)(unsigned long)) raw3215_tasklet, - (unsigned long) raw); init_waitqueue_head(&raw->empty_wait); cdev->dev.driver_data = raw; @@ -863,9 +852,6 @@ con3215_init(void) cdev->handler = raw3215_irq; raw->flags |= RAW3215_FIXED; - tasklet_init(&raw->tasklet, - (void (*)(unsigned long)) raw3215_tasklet, - (unsigned long) raw); init_waitqueue_head(&raw->empty_wait); /* Request the console irq */ -- 2.7.4