lguest: remove obsolete LHREQ_BREAK call

We no longer need an efficient mechanism to force the Guest back into
host userspace, as each device is serviced without bothering the main
Guest process (aka. the Launcher).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index 508569c9571a77b2f31a4ea40bad0945d3713d30..a6974e9b8ebff8c8676f297da0e32a1e3e6d0105 100644 (file)
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -209,10 +209,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
                if (signal_pending(current))
                        return -ERESTARTSYS;
 
-               /* If Waker set break_out, return to Launcher. */
-               if (cpu->break_out)
-                       return -EAGAIN;
-
                /* Check if there are any interrupts which can be delivered now:
                 * if so, this sets up the hander to be executed when we next
                 * run the Guest. */
@@ -231,13 +227,12 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
                        break;
 
                /* If the Guest asked to be stopped, we sleep.  The Guest's
-                * clock timer or LHREQ_BREAK from the Waker will wake us. */
+                * clock timer will wake us. */
                if (cpu->halted) {
                        set_current_state(TASK_INTERRUPTIBLE);
-                       /* Just before we sleep, make sure nothing snuck in
+                       /* Just before we sleep, make sure no interrupt snuck in
                         * which we should be doing. */
-                       if (interrupt_pending(cpu, &more) < LGUEST_IRQS
-                           || cpu->break_out)
+                       if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
                                set_current_state(TASK_RUNNING);
                        else
                                schedule();

diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index 32fefdc6ad3e917854defde0989f8ac42c4f8202..d4e8979735cb002f9f97cf929a1b45a900f2ddc6 100644 (file)
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -71,9 +71,7 @@ struct lg_cpu {
        /* Virtual clock device */
        struct hrtimer hrt;
 
-       /* Do we need to stop what we're doing and return to userspace? */
-       int break_out;
-       wait_queue_head_t break_wq;
+       /* Did the Guest tell us to halt? */
        int halted;
 
        /* Pending virtual interrupts */

diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index f6bf255f183730eccf4f00065e3673d8db6119ac..32e297121058a3d7dc52fbd6d347eab496c08252 100644 (file)
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -11,32 +11,6 @@
 #include <linux/file.h>
 #include "lg.h"
 
-/*L:055 When something happens, the Waker process needs a way to stop the
- * kernel running the Guest and return to the Launcher.  So the Waker writes
- * LHREQ_BREAK and the value "1" to /dev/lguest to do this.  Once the Launcher
- * has done whatever needs attention, it writes LHREQ_BREAK and "0" to release
- * the Waker. */
-static int break_guest_out(struct lg_cpu *cpu, const unsigned long __user*input)
-{
-       unsigned long on;
-
-       /* Fetch whether they're turning break on or off. */
-       if (get_user(on, input) != 0)
-               return -EFAULT;
-
-       if (on) {
-               cpu->break_out = 1;
-               if (!wake_up_process(cpu->tsk))
-                       kick_process(cpu->tsk);
-               /* Wait for them to reset it */
-               return wait_event_interruptible(cpu->break_wq, !cpu->break_out);
-       } else {
-               cpu->break_out = 0;
-               wake_up(&cpu->break_wq);
-               return 0;
-       }
-}
-
 bool send_notify_to_eventfd(struct lg_cpu *cpu)
 {
        unsigned int i;
@@ -202,9 +176,6 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
         * address. */
        lguest_arch_setup_regs(cpu, start_ip);
 
-       /* Initialize the queue for the Waker to wait on */
-       init_waitqueue_head(&cpu->break_wq);
-
        /* We keep a pointer to the Launcher task (ie. current task) for when
         * other Guests want to wake this one (eg. console input). */
        cpu->tsk = current;
@@ -344,8 +315,6 @@ static ssize_t write(struct file *file, const char __user *in,
                return initialize(file, input);
        case LHREQ_IRQ:
                return user_send_irq(cpu, input);
-       case LHREQ_BREAK:
-               return break_guest_out(cpu, input);
        case LHREQ_EVENTFD:
                return attach_eventfd(lg, input);
        default:

diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h
index 9de964b9058648c1905b1e0c13334cae5bdbb0ea..bfefbdf7498a925856ec5e8425a5df24eb4cbac7 100644 (file)
--- a/include/linux/lguest_launcher.h
+++ b/include/linux/lguest_launcher.h
@@ -57,7 +57,7 @@ enum lguest_req
        LHREQ_INITIALIZE, /* + base, pfnlimit, start */
        LHREQ_GETDMA, /* No longer used */
        LHREQ_IRQ, /* + irq */
-       LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
+       LHREQ_BREAK, /* No longer used */
        LHREQ_EVENTFD, /* + address, fd. */
 };