svn commit: r308127 - in head/sys: x86/xen xen
Roger Pau Monné
royger at FreeBSD.org
Mon Oct 31 13:00:54 UTC 2016
Author: royger
Date: Mon Oct 31 13:00:53 2016
New Revision: 308127
URL: https://svnweb.freebsd.org/changeset/base/308127
Log:
xen/intr: add reference counts to event channels
Add a reference count to xenisrc. This is required for implementation of
unmap-notifications in the grant table userspace device (gntdev). We need to
hold a reference to the event channel port, in case the user deallocates the
port before we send the notification.
Submitted by: jaggi
Reviewed by: royger
Differential review: https://reviews.freebsd.org/D7429
Modified:
head/sys/x86/xen/xen_intr.c
head/sys/xen/xen_intr.h
Modified: head/sys/x86/xen/xen_intr.c
==============================================================================
--- head/sys/x86/xen/xen_intr.c Mon Oct 31 11:31:11 2016 (r308126)
+++ head/sys/x86/xen/xen_intr.c Mon Oct 31 13:00:53 2016 (r308127)
@@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
#include <sys/interrupt.h>
#include <sys/pcpu.h>
#include <sys/smp.h>
+#include <sys/refcount.h>
#include <vm/vm.h>
#include <vm/pmap.h>
@@ -128,6 +129,7 @@ struct xenisrc {
u_int xi_activehi:1;
u_int xi_edgetrigger:1;
u_int xi_masked:1;
+ volatile u_int xi_refcount;
};
static void xen_intr_suspend(struct pic *);
@@ -343,10 +345,8 @@ xen_intr_release_isrc(struct xenisrc *is
{
mtx_lock(&xen_intr_isrc_lock);
- if (isrc->xi_intsrc.is_handlers != 0) {
- mtx_unlock(&xen_intr_isrc_lock);
- return (EBUSY);
- }
+ KASSERT(isrc->xi_intsrc.is_handlers == 0,
+ ("Release called, but xenisrc still in use"));
evtchn_mask_port(isrc->xi_port);
evtchn_clear_port(isrc->xi_port);
@@ -417,6 +417,7 @@ xen_intr_bind_isrc(struct xenisrc **isrc
}
isrc->xi_port = local_port;
xen_intr_port_to_isrc[local_port] = isrc;
+ refcount_init(&isrc->xi_refcount, 1);
mtx_unlock(&xen_intr_isrc_lock);
/* Assign the opaque handler (the event channel port) */
@@ -1508,6 +1509,13 @@ xen_intr_unbind(xen_intr_handle_t *port_
if (isrc == NULL)
return;
+ mtx_lock(&xen_intr_isrc_lock);
+ if (refcount_release(&isrc->xi_refcount) == 0) {
+ mtx_unlock(&xen_intr_isrc_lock);
+ return;
+ }
+ mtx_unlock(&xen_intr_isrc_lock);
+
if (isrc->xi_cookie != NULL)
intr_remove_handler(isrc->xi_cookie);
xen_intr_release_isrc(isrc);
@@ -1563,6 +1571,31 @@ xen_intr_add_handler(device_t dev, drive
return (error);
}
+int
+xen_intr_get_evtchn_from_port(evtchn_port_t port, xen_intr_handle_t *handlep)
+{
+
+ if (!is_valid_evtchn(port) || port >= NR_EVENT_CHANNELS)
+ return (EINVAL);
+
+ if (handlep == NULL) {
+ return (EINVAL);
+ }
+
+ mtx_lock(&xen_intr_isrc_lock);
+ if (xen_intr_port_to_isrc[port] == NULL) {
+ mtx_unlock(&xen_intr_isrc_lock);
+ return (EINVAL);
+ }
+ refcount_acquire(&xen_intr_port_to_isrc[port]->xi_refcount);
+ mtx_unlock(&xen_intr_isrc_lock);
+
+ /* Assign the opaque handler (the event channel port) */
+ *handlep = &xen_intr_port_to_isrc[port]->xi_vector;
+
+ return (0);
+}
+
#ifdef DDB
static const char *
xen_intr_print_type(enum evtchn_type type)
Modified: head/sys/xen/xen_intr.h
==============================================================================
--- head/sys/xen/xen_intr.h Mon Oct 31 11:31:11 2016 (r308126)
+++ head/sys/xen/xen_intr.h Mon Oct 31 13:00:53 2016 (r308127)
@@ -263,4 +263,16 @@ int xen_intr_add_handler(device_t dev, d
driver_intr_t handler, void *arg, enum intr_type flags,
xen_intr_handle_t handle);
+/**
+ * Get a reference to an event channel port
+ *
+ * \param port Event channel port to which we get a reference.
+ * \param handlep Pointer to an opaque handle used to manage this
+ * registration.
+ *
+ * \returns 0 on success, otherwise an errno.
+ */
+int xen_intr_get_evtchn_from_port(evtchn_port_t port,
+ xen_intr_handle_t *handlep);
+
#endif /* _XEN_INTR_H_ */
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