diff options
| -rw-r--r-- | drivers/xen/evtchn.c | 96 |
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); } |