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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-11-18 22:43:38 -0800
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-11-18 22:43:38 -0800
commit67cb40560940ba36de22d66f0d5d8efe235c8bb1 (patch)
tree1bc7f165e7ddaef5792fc13b4cc56b2c2b700725 /drivers/xen/evtchn.c
parentbc7fc5e33e1a093e5f9e196595843bb096471586 (diff)
parent70697d540c0598ad023a391d4c895044db9a6624 (diff)
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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
Diffstat (limited to 'drivers/xen/evtchn.c')
-rw-r--r--drivers/xen/evtchn.c96
1 files changed, 74 insertions, 22 deletions
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index dd8e5e0f193..ef11daf0caf 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -69,20 +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 @@ irqreturn_t evtchn_interrupt(int irq, void *data)
kill_fasync(&u->evtchn_async_queue,
SIGIO, POLL_IN);
}
- } else {
+ } else
u->ring_overflow = 1;
- }
spin_unlock(&port_user_lock);
@@ -198,9 +228,18 @@ static ssize_t evtchn_write(struct file *file, const char __user *buf,
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 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port)
* 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 @@ static void evtchn_unbind_from_user(struct per_user_data *u, int port)
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 @@ static long evtchn_ioctl(struct file *file,
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 @@ static long evtchn_ioctl(struct file *file,
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);
@@ -444,14 +483,21 @@ static int evtchn_release(struct inode *inode, struct file *filp)
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);
@@ -472,7 +518,7 @@ static const struct file_operations evtchn_fops = {
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 +528,11 @@ static int __init evtchn_init(void)
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 +548,9 @@ static int __init evtchn_init(void)
static void __exit evtchn_cleanup(void)
{
+ kfree(port_user);
+ port_user = NULL;
+
misc_deregister(&evtchn_miscdev);
}