From: Christian Borntraeger Date: Fri, 20 Jun 2008 13:24:08 +0000 (+0200) Subject: hvc_console: rework setup to replace irq functions with callbacks X-Git-Tag: v2.6.27-rc1~504^2~6 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=611e097d7707741a336a0677d9d69bec40f29f3d;p=linux-2.6 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 Signed-off-by: Rusty Russell --- diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 67b07576f8..d825361a6b 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 4b6e736cfa..eb02c35068 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 2f9759d625..2f5b7fb670 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -27,7 +27,6 @@ #include #include #include -#include #include #include #include @@ -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 42ffb17e15..d9ce109156 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 /* * 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 diff --git a/drivers/char/hvc_irq.c b/drivers/char/hvc_irq.c new file mode 100644 index 0000000000..73a59cdb89 --- /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 + +#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 a08f8f981c..b71c610fe5 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 79711aa4b4..93f3840c16 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 db2ae42162..6b70aa66a5 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)