611e097d77
This patch tries to change hvc_console to not use request_irq/free_irq if the backend does not use irqs. This allows virtio_console to use hvc_console without having a linker reference to request_irq/free_irq. In addition, together with patch 2/3 it improves the performance for virtio console input. (an earlier version of this patch was tested by Yajin on lguest) The irq specific code is moved to hvc_irq.c and selected by the drivers that use irqs (System p, System i, XEN). I replaced "int irq" with the opaque "int data". The request_irq and free_irq calls are replaced with notifier_add and notifier_del. I have also changed the code a bit to call the notifier_add and notifier_del inside the spinlock area as the callbacks are found via hp->ops. Changes since last version: o remove ifdef o reintroduce "irq_requested" as "notified" o cleanups, sparse.. I did not move the timer based polling into a separate polling scheme. I played with several variants, but it seems we need to sleep/schedule in a thread even for irq based consoles, as there are throttleing and buffer size constraints. I also kept hvc_struct defined in hvc_console.h so that hvc_irq.c can access the irq_requested element. Feedback is appreciated. virtio_console is currently the only available console for kvm on s390. I plan to push this change as soon as all affected parties agree on it. I would love to get test results from System p, Xen etc. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
44 lines
801 B
C
44 lines
801 B
C
/*
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* Copyright IBM Corp. 2001,2008
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*
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* This file contains the IRQ specific code for hvc_console
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*
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*/
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#include <linux/interrupt.h>
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#include "hvc_console.h"
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static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
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{
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/* if hvc_poll request a repoll, then kick the hvcd thread */
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if (hvc_poll(dev_instance))
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hvc_kick();
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return IRQ_HANDLED;
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}
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/*
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* For IRQ based systems these callbacks can be used
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*/
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int notifier_add_irq(struct hvc_struct *hp, int irq)
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{
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int rc;
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if (!irq) {
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hp->irq_requested = 0;
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return 0;
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}
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rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED,
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"hvc_console", hp);
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if (!rc)
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hp->irq_requested = 1;
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return rc;
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}
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void notifier_del_irq(struct hvc_struct *hp, int irq)
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{
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if (!irq)
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return;
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free_irq(irq, hp);
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hp->irq_requested = 0;
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}
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