Merge branch 'xen/dev-evtchn' into upstream/evtchn

* xen/dev-evtchn:
  xen/evtchn: add missing static
  xen/evtchn: Fix name of Xen event-channel device
  xen/evtchn: don't do unbind_from_irqhandler under spinlock
  xen/evtchn: remove spurious barrier
  xen/evtchn: ports start enabled
  xen/evtchn: dynamically allocate port_user array
  xen/evtchn: track enabled state for each port

diff --combined drivers/xen/evtchn.c
index dd8e5e0f19352a56f2d645cbf8941fc620f26207,f3594ec2ee332b3ca0b293b82275c9be16a18aac..ef11daf0cafe9f086f3944b42fd32ff48811f4b2
--- 1/drivers/xen/evtchn.c
--- 2/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@@ -38,6 -38,7 +38,6 @@@
  #include <linux/string.h>
  #include <linux/errno.h>
  #include <linux/fs.h>
 -#include <linux/errno.h>
  #include <linux/miscdevice.h>
  #include <linux/major.h>
  #include <linux/proc_fs.h>
@@@ -45,10 -46,9 +45,10 @@@
  #include <linux/poll.h>
  #include <linux/irq.h>
  #include <linux/init.h>
 -#include <linux/gfp.h>
  #include <linux/mutex.h>
  #include <linux/cpu.h>
 +
 +#include <xen/xen.h>
  #include <xen/events.h>
  #include <xen/evtchn.h>
  #include <asm/xen/hypervisor.h>
@@@ -69,20 -69,51 +69,51 @@@ struct per_user_data 
        const char *name;
  };
  
- /* Who's bound to each port? */
- static struct per_user_data *port_user[NR_EVENT_CHANNELS];
+ /*
+  * Who's bound to each port?  This is logically an array of struct
+  * per_user_data *, but we encode the current enabled-state in bit 0.
+  */
+ static unsigned long *port_user;
  static DEFINE_SPINLOCK(port_user_lock); /* protects port_user[] and ring_prod */
  
- irqreturn_t evtchn_interrupt(int irq, void *data)
+ static inline struct per_user_data *get_port_user(unsigned port)
+ {
+       return (struct per_user_data *)(port_user[port] & ~1);
+ }
+ 
+ static inline void set_port_user(unsigned port, struct per_user_data *u)
+ {
+       port_user[port] = (unsigned long)u;
+ }
+ 
+ static inline bool get_port_enabled(unsigned port)
+ {
+       return port_user[port] & 1;
+ }
+ 
+ static inline void set_port_enabled(unsigned port, bool enabled)
+ {
+       if (enabled)
+               port_user[port] |= 1;
+       else
+               port_user[port] &= ~1;
+ }
+ 
+ static irqreturn_t evtchn_interrupt(int irq, void *data)
  {
        unsigned int port = (unsigned long)data;
        struct per_user_data *u;
  
        spin_lock(&port_user_lock);
  
-       u = port_user[port];
+       u = get_port_user(port);
+ 
+       WARN(!get_port_enabled(port),
+            "Interrupt for port %d, but apparently not enabled; per-user %p\n",
+            port, u);
  
        disable_irq_nosync(irq);
+       set_port_enabled(port, false);
  
        if ((u->ring_prod - u->ring_cons) < EVTCHN_RING_SIZE) {
                u->ring[EVTCHN_RING_MASK(u->ring_prod)] = port;
@@@ -92,9 -123,8 +123,8 @@@
                        kill_fasync(&u->evtchn_async_queue,
                                    SIGIO, POLL_IN);
                }
-       } else {
+       } else
                u->ring_overflow = 1;
-       }
  
        spin_unlock(&port_user_lock);
  
@@@ -198,9 -228,18 +228,18 @@@ static ssize_t evtchn_write(struct fil
                goto out;
  
        spin_lock_irq(&port_user_lock);
-       for (i = 0; i < (count/sizeof(evtchn_port_t)); i++)
-               if ((kbuf[i] < NR_EVENT_CHANNELS) && (port_user[kbuf[i]] == u))
-                       enable_irq(irq_from_evtchn(kbuf[i]));
+ 
+       for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
+               unsigned port = kbuf[i];
+ 
+               if (port < NR_EVENT_CHANNELS &&
+                   get_port_user(port) == u &&
+                   !get_port_enabled(port)) {
+                       set_port_enabled(port, true);
+                       enable_irq(irq_from_evtchn(port));
+               }
+       }
+ 
        spin_unlock_irq(&port_user_lock);
  
        rc = count;
@@@ -222,8 -261,9 +261,9 @@@ static int evtchn_bind_to_user(struct p
         * interrupt handler yet, and our caller has already
         * serialized bind operations.)
         */
-       BUG_ON(port_user[port] != NULL);
-       port_user[port] = u;
+       BUG_ON(get_port_user(port) != NULL);
+       set_port_user(port, u);
+       set_port_enabled(port, true); /* start enabled */
  
        rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, IRQF_DISABLED,
                                       u->name, (void *)(unsigned long)port);
@@@ -239,10 -279,7 +279,7 @@@ static void evtchn_unbind_from_user(str
  
        unbind_from_irqhandler(irq, (void *)(unsigned long)port);
  
-       /* make sure we unbind the irq handler before clearing the port */
-       barrier();
- 
-       port_user[port] = NULL;
+       set_port_user(port, NULL);
  }
  
  static long evtchn_ioctl(struct file *file,
@@@ -333,15 -370,17 +370,17 @@@
                spin_lock_irq(&port_user_lock);
  
                rc = -ENOTCONN;
-               if (port_user[unbind.port] != u) {
+               if (get_port_user(unbind.port) != u) {
                        spin_unlock_irq(&port_user_lock);
                        break;
                }
  
-               evtchn_unbind_from_user(u, unbind.port);
+               disable_irq(irq_from_evtchn(unbind.port));
  
                spin_unlock_irq(&port_user_lock);
  
+               evtchn_unbind_from_user(u, unbind.port);
+ 
                rc = 0;
                break;
        }
@@@ -355,7 -394,7 +394,7 @@@
  
                if (notify.port >= NR_EVENT_CHANNELS) {
                        rc = -EINVAL;
-               } else if (port_user[notify.port] != u) {
+               } else if (get_port_user(notify.port) != u) {
                        rc = -ENOTCONN;
                } else {
                        notify_remote_via_evtchn(notify.port);
@@@ -431,7 -470,7 +470,7 @@@ static int evtchn_open(struct inode *in
  
        filp->private_data = u;
  
 -      return 0;
 +      return nonseekable_open(inode, filp);;
  }
  
  static int evtchn_release(struct inode *inode, struct file *filp)
@@@ -444,14 -483,21 +483,21 @@@
        free_page((unsigned long)u->ring);
  
        for (i = 0; i < NR_EVENT_CHANNELS; i++) {
-               if (port_user[i] != u)
+               if (get_port_user(i) != u)
                        continue;
  
-               evtchn_unbind_from_user(port_user[i], i);
+               disable_irq(irq_from_evtchn(i));
        }
  
        spin_unlock_irq(&port_user_lock);
  
+       for (i = 0; i < NR_EVENT_CHANNELS; i++) {
+               if (get_port_user(i) != u)
+                       continue;
+ 
+               evtchn_unbind_from_user(get_port_user(i), i);
+       }
+ 
        kfree(u->name);
        kfree(u);
  
@@@ -467,12 -513,11 +513,12 @@@ static const struct file_operations evt
        .fasync  = evtchn_fasync,
        .open    = evtchn_open,
        .release = evtchn_release,
 +      .llseek  = no_llseek,
  };
  
  static struct miscdevice evtchn_miscdev = {
        .minor        = MISC_DYNAMIC_MINOR,
-       .name         = "evtchn",
+       .name         = "xen/evtchn",
        .fops         = &evtchn_fops,
  };
  static int __init evtchn_init(void)
@@@ -482,8 -527,11 +528,11 @@@
        if (!xen_domain())
                return -ENODEV;
  
+       port_user = kcalloc(NR_EVENT_CHANNELS, sizeof(*port_user), GFP_KERNEL);
+       if (port_user == NULL)
+               return -ENOMEM;
+ 
        spin_lock_init(&port_user_lock);
-       memset(port_user, 0, sizeof(port_user));
  
        /* Create '/dev/misc/evtchn'. */
        err = misc_register(&evtchn_miscdev);
@@@ -499,6 -547,9 +548,9 @@@
  
  static void __exit evtchn_cleanup(void)
  {
+       kfree(port_user);
+       port_user = NULL;
+ 
        misc_deregister(&evtchn_miscdev);
  }