Simplify console driver and avoid unnecessary spinning in the

transmit handler.

Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c b/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
index 6431722c25d0593eea8d2a32472b07b80fbed645..c904a1fd44c671e501d155d5a3988d11598a7d24 100644 (file)
--- a/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
+++ b/linux-2.6-xen-sparse/arch/xen/i386/mm/pgtable.c
@@ -389,7 +389,6 @@ void pgd_free(pgd_t *pgd)
 }
 
 #ifndef CONFIG_XEN_SHADOW_MODE
-asmlinkage int xprintk(const char *fmt, ...);
 void make_lowmem_page_readonly(void *va)
 {
        pte_t *pte = virt_to_ptep(va);

diff --git a/linux-2.6-xen-sparse/drivers/xen/console/console.c b/linux-2.6-xen-sparse/drivers/xen/console/console.c
index 137af277f3df0d9fd91a66049e3acfb55ba0fda5..22f18b1511b1561bfde148a1961f38a7a44e42ae 100644 (file)
--- a/linux-2.6-xen-sparse/drivers/xen/console/console.c
+++ b/linux-2.6-xen-sparse/drivers/xen/console/console.c
@@ -55,7 +55,6 @@
 #include <asm-xen/evtchn.h>
 #include <asm-xen/xencons.h>
 
-#include "xencons_ring.h"
 /*
  * Modes:
  *  'xencons=off'  [XC_OFF]:     Console is disabled.
@@ -247,7 +246,6 @@ void xencons_force_flush(void)
        if (xen_start_info->flags & SIF_INITDOMAIN)
                return;
 
-
        /* Spin until console data is flushed through to the daemon. */
        while (wc != wp) {
                int sent = 0;
@@ -271,8 +269,7 @@ static struct tty_struct *xencons_tty;
 static int xencons_priv_irq;
 static char x_char;
 
-/* Non-privileged receive callback. */
-static void xencons_rx(char *buf, unsigned len, struct pt_regs *regs)
+void xencons_rx(char *buf, unsigned len, struct pt_regs *regs)
 {
        int           i;
        unsigned long flags;
@@ -311,10 +308,9 @@ static void xencons_rx(char *buf, unsigned len, struct pt_regs *regs)
        spin_unlock_irqrestore(&xencons_lock, flags);
 }
 
-/* Privileged and non-privileged transmit worker. */
 static void __xencons_tx_flush(void)
 {
-       int sz, work_done = 0;
+       int sent, sz, work_done = 0;
 
        if (xen_start_info->flags & SIF_INITDOMAIN) {
                if (x_char) {
@@ -340,20 +336,18 @@ static void __xencons_tx_flush(void)
                }
 
                while (wc != wp) {
-                       int sent;
                        sz = wp - wc;
                        if (sz > (wbuf_size - WBUF_MASK(wc)))
                                sz = wbuf_size - WBUF_MASK(wc);
                        sent = xencons_ring_send(&wbuf[WBUF_MASK(wc)], sz);
-                       if (sent > 0) {
-                               wc += sent;
-                               work_done = 1;
-                       }
+                       if (sent == 0)
+                               break;
+                       wc += sent;
+                       work_done = 1;
                }
        }
 
-       if (work_done && (xencons_tty != NULL))
-       {
+       if (work_done && (xencons_tty != NULL)) {
                wake_up_interruptible(&xencons_tty->write_wait);
                if ((xencons_tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
                    (xencons_tty->ldisc.write_wakeup != NULL))
@@ -361,31 +355,26 @@ static void __xencons_tx_flush(void)
        }
 }
 
-/* Privileged receive callback and transmit kicker. */
-static irqreturn_t xencons_priv_interrupt(int irq, void *dev_id,
-                                          struct pt_regs *regs)
+void xencons_tx(void)
 {
-       static char   rbuf[16];
-       int           i, l;
        unsigned long flags;
 
        spin_lock_irqsave(&xencons_lock, flags);
+       __xencons_tx_flush();
+       spin_unlock_irqrestore(&xencons_lock, flags);
+}
 
-       if (xencons_tty != NULL)
-       {
-               /* Receive work. */
-               while ((l = HYPERVISOR_console_io(
-                       CONSOLEIO_read, 16, rbuf)) > 0)
-                       for (i = 0; i < l; i++)
-                               tty_insert_flip_char(xencons_tty, rbuf[i], 0);
-               if (xencons_tty->flip.count != 0)
-                       tty_flip_buffer_push(xencons_tty);
-       }
+/* Privileged receive callback and transmit kicker. */
+static irqreturn_t xencons_priv_interrupt(int irq, void *dev_id,
+                                          struct pt_regs *regs)
+{
+       static char rbuf[16];
+       int         l;
 
-       /* Transmit work. */
-       __xencons_tx_flush();
+       while ((l = HYPERVISOR_console_io(CONSOLEIO_read, 16, rbuf)) > 0)
+               xencons_rx(rbuf, l, regs);
 
-       spin_unlock_irqrestore(&xencons_lock, flags);
+       xencons_tx();
 
        return IRQ_HANDLED;
 }
@@ -664,7 +653,8 @@ static int __init xencons_init(void)
        if ((rc = tty_register_driver(DRV(xencons_driver))) != 0) {
                printk("WARNING: Failed to register Xen virtual "
                       "console driver as '%s%d'\n",
-                      DRV(xencons_driver)->name, DRV(xencons_driver)->name_base);
+                      DRV(xencons_driver)->name,
+                      DRV(xencons_driver)->name_base);
                put_tty_driver(xencons_driver);
                xencons_driver = NULL;
                return rc;
@@ -681,8 +671,6 @@ static int __init xencons_init(void)
                        "console",
                        NULL);
                BUG_ON(xencons_priv_irq < 0);
-       } else {
-               xencons_ring_register_receiver(xencons_rx);
        }
 
        printk("Xen virtual console successfully installed as %s%d\n",

diff --git a/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.c b/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.c
index 2d6eb044b60ffc2b6f039580a37bd20d17795d6c..ea7bfe4e22bd7d27f8c24537eb884b6882fd3313 100644 (file)
--- a/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.c
+++ b/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.c
@@ -19,11 +19,9 @@
 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/err.h>
-#include "xencons_ring.h"
 #include <asm-xen/xen-public/io/console.h>
 
 static int xencons_irq;
-static xencons_receiver_func *xencons_receiver;
 
 static inline struct xencons_interface *xencons_interface(void)
 {
@@ -69,10 +67,8 @@ static irqreturn_t handle_input(int irq, void *unused, struct pt_regs *regs)
        BUG_ON((prod - cons) > sizeof(intf->in));
 
        while (cons != prod) {
-               if (xencons_receiver != NULL)
-                       xencons_receiver(
-                               intf->in + MASK_XENCONS_IDX(cons++, intf->in),
-                               1, regs);
+               xencons_rx(intf->in+MASK_XENCONS_IDX(cons,intf->in), 1, regs);
+               cons++;
        }
 
        mb();
@@ -80,12 +76,9 @@ static irqreturn_t handle_input(int irq, void *unused, struct pt_regs *regs)
 
        notify_daemon();
 
-       return IRQ_HANDLED;
-}
+       xencons_tx();
 
-void xencons_ring_register_receiver(xencons_receiver_func *f)
-{
-       xencons_receiver = f;
+       return IRQ_HANDLED;
 }
 
 int xencons_ring_init(void)

diff --git a/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.h b/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.h
deleted file mode 100644 (file)
index 25af210..0000000
--- a/linux-2.6-xen-sparse/drivers/xen/console/xencons_ring.h
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef _XENCONS_RING_H
-#define _XENCONS_RING_H
-
-asmlinkage int xprintk(const char *fmt, ...);
-
-int xencons_ring_init(void);
-int xencons_ring_send(const char *data, unsigned len);
-
-typedef void (xencons_receiver_func)(
-       char *buf, unsigned len, struct pt_regs *regs);
-void xencons_ring_register_receiver(xencons_receiver_func *f);
-
-#endif /* _XENCONS_RING_H */
-
-/*
- * Local variables:
- *  c-file-style: "linux"
- *  indent-tabs-mode: t
- *  c-indent-level: 8
- *  c-basic-offset: 8
- *  tab-width: 8
- * End:
- */

diff --git a/linux-2.6-xen-sparse/include/asm-xen/xencons.h b/linux-2.6-xen-sparse/include/asm-xen/xencons.h
index 4b4909ba91bea20678916dddb4664732a6b8feaa..fa2160d89d6ff7da9171d7acc51428cb61029176 100644 (file)
--- a/linux-2.6-xen-sparse/include/asm-xen/xencons.h
+++ b/linux-2.6-xen-sparse/include/asm-xen/xencons.h
@@ -4,4 +4,11 @@
 void xencons_force_flush(void);
 void xencons_resume(void);
 
+/* Interrupt work hooks. Receive data, or kick data out. */
+void xencons_rx(char *buf, unsigned len, struct pt_regs *regs);
+void xencons_tx(void);
+
+int xencons_ring_init(void);
+int xencons_ring_send(const char *data, unsigned len);
+
 #endif /* __ASM_XENCONS_H__ */