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authorChristian Borntraeger <borntraeger@de.ibm.com>2008-06-20 15:24:08 +0200
committerRusty Russell <rusty@rustcorp.com.au>2008-07-25 12:06:06 +1000
commit611e097d7707741a336a0677d9d69bec40f29f3d (patch)
tree0b0059544914bf027ada51a1ba90f694c54df835
parent066f4d82a67f621ddd547bfa4b9c94631d8457b0 (diff)
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hvc_console: rework setup to replace irq functions with callbacks
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>
-rw-r--r--drivers/char/Kconfig5
-rw-r--r--drivers/char/Makefile1
-rw-r--r--drivers/char/hvc_console.c81
-rw-r--r--drivers/char/hvc_console.h35
-rw-r--r--drivers/char/hvc_irq.c44
-rw-r--r--drivers/char/hvc_iseries.c2
-rw-r--r--drivers/char/hvc_vio.c2
-rw-r--r--drivers/char/hvc_xen.c2
8 files changed, 105 insertions, 67 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 67b07576f8b..d825361a6ba 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -578,11 +578,14 @@ config HVC_DRIVER
It will automatically be selected if one of the back-end console drivers
is selected.
+config HVC_IRQ
+ bool
config HVC_CONSOLE
bool "pSeries Hypervisor Virtual Console support"
depends on PPC_PSERIES
select HVC_DRIVER
+ select HVC_IRQ
help
pSeries machines when partitioned support a hypervisor virtual
console. This driver allows each pSeries partition to have a console
@@ -593,6 +596,7 @@ config HVC_ISERIES
depends on PPC_ISERIES
default y
select HVC_DRIVER
+ select HVC_IRQ
help
iSeries machines support a hypervisor virtual console.
@@ -614,6 +618,7 @@ config HVC_XEN
bool "Xen Hypervisor Console support"
depends on XEN
select HVC_DRIVER
+ select HVC_IRQ
default y
help
Xen virtual console device driver
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 4b6e736cfa0..eb02c350680 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_HVC_ISERIES) += hvc_iseries.o
obj-$(CONFIG_HVC_RTAS) += hvc_rtas.o
obj-$(CONFIG_HVC_BEAT) += hvc_beat.o
obj-$(CONFIG_HVC_DRIVER) += hvc_console.o
+obj-$(CONFIG_HVC_IRQ) += hvc_irq.o
obj-$(CONFIG_HVC_XEN) += hvc_xen.o
obj-$(CONFIG_VIRTIO_CONSOLE) += virtio_console.o
obj-$(CONFIG_RAW_DRIVER) += raw.o
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 2f9759d625c..2f5b7fb6704 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -27,7 +27,6 @@
#include <linux/init.h>
#include <linux/kbd_kern.h>
#include <linux/kernel.h>
-#include <linux/kref.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/module.h>
@@ -75,23 +74,6 @@ static int hvc_init(void);
static int sysrq_pressed;
#endif
-struct hvc_struct {
- spinlock_t lock;
- int index;
- struct tty_struct *tty;
- unsigned int count;
- int do_wakeup;
- char *outbuf;
- int outbuf_size;
- int n_outbuf;
- uint32_t vtermno;
- struct hv_ops *ops;
- int irq_requested;
- int irq;
- struct list_head next;
- struct kref kref; /* ref count & hvc_struct lifetime */
-};
-
/* dynamic list of hvc_struct instances */
static LIST_HEAD(hvc_structs);
@@ -300,26 +282,12 @@ int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
}
/* Wake the sleeping khvcd */
-static void hvc_kick(void)
+void hvc_kick(void)
{
hvc_kicked = 1;
wake_up_process(hvc_task);
}
-static int hvc_poll(struct hvc_struct *hp);
-
-/*
- * NOTE: This API isn't used if the console adapter doesn't support interrupts.
- * In this case the console is poll driven.
- */
-static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
-{
- /* if hvc_poll request a repoll, then kick the hvcd thread */
- if (hvc_poll(dev_instance))
- hvc_kick();
- return IRQ_HANDLED;
-}
-
static void hvc_unthrottle(struct tty_struct *tty)
{
hvc_kick();
@@ -333,7 +301,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
{
struct hvc_struct *hp;
unsigned long flags;
- int irq = 0;
int rc = 0;
/* Auto increments kref reference if found. */
@@ -352,18 +319,15 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
tty->low_latency = 1; /* Makes flushes to ldisc synchronous. */
hp->tty = tty;
- /* Save for request_irq outside of spin_lock. */
- irq = hp->irq;
- if (irq)
- hp->irq_requested = 1;
+
+ if (hp->ops->notifier_add)
+ rc = hp->ops->notifier_add(hp, hp->data);
spin_unlock_irqrestore(&hp->lock, flags);
- /* check error, fallback to non-irq */
- if (irq)
- rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp);
+
/*
- * If the request_irq() fails and we return an error. The tty layer
+ * If the notifier fails we return an error. The tty layer
* will call hvc_close() after a failed open but we don't want to clean
* up there so we'll clean up here and clear out the previously set
* tty fields and return the kref reference.
@@ -371,7 +335,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
if (rc) {
spin_lock_irqsave(&hp->lock, flags);
hp->tty = NULL;
- hp->irq_requested = 0;
spin_unlock_irqrestore(&hp->lock, flags);
tty->driver_data = NULL;
kref_put(&hp->kref, destroy_hvc_struct);
@@ -386,7 +349,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
static void hvc_close(struct tty_struct *tty, struct file * filp)
{
struct hvc_struct *hp;
- int irq = 0;
unsigned long flags;
if (tty_hung_up_p(filp))
@@ -404,9 +366,8 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
spin_lock_irqsave(&hp->lock, flags);
if (--hp->count == 0) {
- if (hp->irq_requested)
- irq = hp->irq;
- hp->irq_requested = 0;
+ if (hp->ops->notifier_del)
+ hp->ops->notifier_del(hp, hp->data);
/* We are done with the tty pointer now. */
hp->tty = NULL;
@@ -418,10 +379,6 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
* waking periodically to check chars_in_buffer().
*/
tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
-
- if (irq)
- free_irq(irq, hp);
-
} else {
if (hp->count < 0)
printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
@@ -436,7 +393,6 @@ static void hvc_hangup(struct tty_struct *tty)
{
struct hvc_struct *hp = tty->driver_data;
unsigned long flags;
- int irq = 0;
int temp_open_count;
if (!hp)
@@ -458,13 +414,12 @@ static void hvc_hangup(struct tty_struct *tty)
hp->count = 0;
hp->n_outbuf = 0;
hp->tty = NULL;
- if (hp->irq_requested)
- /* Saved for use outside of spin_lock. */
- irq = hp->irq;
- hp->irq_requested = 0;
+
+ if (hp->ops->notifier_del)
+ hp->ops->notifier_del(hp, hp->data);
+
spin_unlock_irqrestore(&hp->lock, flags);
- if (irq)
- free_irq(irq, hp);
+
while(temp_open_count) {
--temp_open_count;
kref_put(&hp->kref, destroy_hvc_struct);
@@ -575,7 +530,7 @@ static u32 timeout = MIN_TIMEOUT;
#define HVC_POLL_READ 0x00000001
#define HVC_POLL_WRITE 0x00000002
-static int hvc_poll(struct hvc_struct *hp)
+int hvc_poll(struct hvc_struct *hp)
{
struct tty_struct *tty;
int i, n, poll_mask = 0;
@@ -602,10 +557,10 @@ static int hvc_poll(struct hvc_struct *hp)
if (test_bit(TTY_THROTTLED, &tty->flags))
goto throttled;
- /* If we aren't interrupt driven and aren't throttled, we always
+ /* If we aren't notifier driven and aren't throttled, we always
* request a reschedule
*/
- if (hp->irq == 0)
+ if (!hp->irq_requested)
poll_mask |= HVC_POLL_READ;
/* Read data if any */
@@ -733,7 +688,7 @@ static const struct tty_operations hvc_ops = {
.chars_in_buffer = hvc_chars_in_buffer,
};
-struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
+struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int data,
struct hv_ops *ops, int outbuf_size)
{
struct hvc_struct *hp;
@@ -754,7 +709,7 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
memset(hp, 0x00, sizeof(*hp));
hp->vtermno = vtermno;
- hp->irq = irq;
+ hp->data = data;
hp->ops = ops;
hp->outbuf_size = outbuf_size;
hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
diff --git a/drivers/char/hvc_console.h b/drivers/char/hvc_console.h
index 42ffb17e15d..d9ce1091562 100644
--- a/drivers/char/hvc_console.h
+++ b/drivers/char/hvc_console.h
@@ -26,6 +26,7 @@
#ifndef HVC_CONSOLE_H
#define HVC_CONSOLE_H
+#include <linux/kref.h>
/*
* This is the max number of console adapters that can/will be found as
@@ -42,24 +43,50 @@
*/
#define HVC_ALLOC_TTY_ADAPTERS 8
+struct hvc_struct {
+ spinlock_t lock;
+ int index;
+ struct tty_struct *tty;
+ unsigned int count;
+ int do_wakeup;
+ char *outbuf;
+ int outbuf_size;
+ int n_outbuf;
+ uint32_t vtermno;
+ struct hv_ops *ops;
+ int irq_requested;
+ int data;
+ struct list_head next;
+ struct kref kref; /* ref count & hvc_struct lifetime */
+};
/* implemented by a low level driver */
struct hv_ops {
int (*get_chars)(uint32_t vtermno, char *buf, int count);
int (*put_chars)(uint32_t vtermno, const char *buf, int count);
-};
-struct hvc_struct;
+ /* Callbacks for notification. Called in open and close */
+ int (*notifier_add)(struct hvc_struct *hp, int irq);
+ void (*notifier_del)(struct hvc_struct *hp, int irq);
+};
/* Register a vterm and a slot index for use as a console (console_init) */
extern int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops);
/* register a vterm for hvc tty operation (module_init or hotplug add) */
-extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int irq,
+extern struct hvc_struct * __devinit hvc_alloc(uint32_t vtermno, int data,
struct hv_ops *ops, int outbuf_size);
-/* remove a vterm from hvc tty operation (modele_exit or hotplug remove) */
+/* remove a vterm from hvc tty operation (module_exit or hotplug remove) */
extern int __devexit hvc_remove(struct hvc_struct *hp);
+/* data available */
+int hvc_poll(struct hvc_struct *hp);
+void hvc_kick(void);
+
+/* default notifier for irq based notification */
+extern int notifier_add_irq(struct hvc_struct *hp, int data);
+extern void notifier_del_irq(struct hvc_struct *hp, int data);
+
#if defined(CONFIG_XMON) && defined(CONFIG_SMP)
#include <asm/xmon.h>
diff --git a/drivers/char/hvc_irq.c b/drivers/char/hvc_irq.c
new file mode 100644
index 00000000000..73a59cdb894
--- /dev/null
+++ b/drivers/char/hvc_irq.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright IBM Corp. 2001,2008
+ *
+ * This file contains the IRQ specific code for hvc_console
+ *
+ */
+
+#include <linux/interrupt.h>
+
+#include "hvc_console.h"
+
+static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance)
+{
+ /* if hvc_poll request a repoll, then kick the hvcd thread */
+ if (hvc_poll(dev_instance))
+ hvc_kick();
+ return IRQ_HANDLED;
+}
+
+/*
+ * For IRQ based systems these callbacks can be used
+ */
+int notifier_add_irq(struct hvc_struct *hp, int irq)
+{
+ int rc;
+
+ if (!irq) {
+ hp->irq_requested = 0;
+ return 0;
+ }
+ rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED,
+ "hvc_console", hp);
+ if (!rc)
+ hp->irq_requested = 1;
+ return rc;
+}
+
+void notifier_del_irq(struct hvc_struct *hp, int irq)
+{
+ if (!irq)
+ return;
+ free_irq(irq, hp);
+ hp->irq_requested = 0;
+}
diff --git a/drivers/char/hvc_iseries.c b/drivers/char/hvc_iseries.c
index a08f8f981c1..b71c610fe5a 100644
--- a/drivers/char/hvc_iseries.c
+++ b/drivers/char/hvc_iseries.c
@@ -200,6 +200,8 @@ done:
static struct hv_ops hvc_get_put_ops = {
.get_chars = get_chars,
.put_chars = put_chars,
+ .notifier_add = notifier_add_irq,
+ .notifier_del = notifier_del_irq,
};
static int __devinit hvc_vio_probe(struct vio_dev *vdev,
diff --git a/drivers/char/hvc_vio.c b/drivers/char/hvc_vio.c
index 79711aa4b41..93f3840c168 100644
--- a/drivers/char/hvc_vio.c
+++ b/drivers/char/hvc_vio.c
@@ -80,6 +80,8 @@ static int filtered_get_chars(uint32_t vtermno, char *buf, int count)
static struct hv_ops hvc_get_put_ops = {
.get_chars = filtered_get_chars,
.put_chars = hvc_put_chars,
+ .notifier_add = notifier_add_irq,
+ .notifier_del = notifier_del_irq,
};
static int __devinit hvc_vio_probe(struct vio_dev *vdev,
diff --git a/drivers/char/hvc_xen.c b/drivers/char/hvc_xen.c
index db2ae421627..6b70aa66a58 100644
--- a/drivers/char/hvc_xen.c
+++ b/drivers/char/hvc_xen.c
@@ -100,6 +100,8 @@ static int read_console(uint32_t vtermno, char *buf, int len)
static struct hv_ops hvc_ops = {
.get_chars = read_console,
.put_chars = write_console,
+ .notifier_add = notifier_add_irq,
+ .notifier_del = notifier_del_irq,
};
static int __init xen_init(void)