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_ */ _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
