int
xb_write(const void *data, unsigned len)
{
volatile struct xenstore_domain_interface *intf =
xs_domain_interface(xb_addr);
XENSTORE_RING_IDX cons, prod;
extern int do_polled_io;
while (len != 0) {
void *dst;
unsigned int avail;
mutex_enter(&xb_wait_lock);
while ((intf->req_prod - intf->req_cons) ==
XENSTORE_RING_SIZE) {
if (interrupts_unleashed && !do_polled_io) {
if (cv_wait_sig(&xb_wait_cv,
&xb_wait_lock) == 0) {
mutex_exit(&xb_wait_lock);
return (EINTR);
}
} else { /* polled mode needed for early probes */
(void) HYPERVISOR_yield();
}
}
mutex_exit(&xb_wait_lock);
/* Read indexes, then verify. */
cons = intf->req_cons;
prod = intf->req_prod;
membar_enter();
if (!check_indexes(cons, prod))
return (EIO);
dst = get_output_chunk(cons, prod, (char *)intf->req, &avail);
if (avail == 0)
continue;
if (avail > len)
avail = len;
(void) memcpy(dst, data, avail);
data = (void *)((uintptr_t)data + avail);
len -= avail;
/* Other side must not see new header until data is there. */
membar_producer();
intf->req_prod += avail;
/* This implies mb() before other side sees interrupt. */
ec_notify_via_evtchn(xen_info->store_evtchn);
}
return (0);
}
/**
* xb_write - low level write
* @data: buffer to send
* @len: length of buffer
*
* Returns 0 on success, error otherwise.
*/
int xb_write(const void *data, unsigned len)
{
struct xenstore_domain_interface *intf = xen_store_interface;
XENSTORE_RING_IDX cons, prod;
int rc;
while (len != 0) {
void *dst;
unsigned int avail;
rc = wait_event_interruptible(
xb_waitq,
(intf->req_prod - intf->req_cons) !=
XENSTORE_RING_SIZE);
if (rc < 0)
return rc;
/* Read indexes, then verify. */
cons = intf->req_cons;
prod = intf->req_prod;
if (!check_indexes(cons, prod)) {
intf->req_cons = intf->req_prod = 0;
return -EIO;
}
dst = get_output_chunk(cons, prod, intf->req, &avail);
if (avail == 0)
continue;
if (avail > len)
avail = len;
/* Must write data /after/ reading the consumer index. */
mb();
memcpy(dst, data, avail);
data += avail;
len -= avail;
/* Other side must not see new producer until data is there. */
wmb();
intf->req_prod += avail;
/* Implies mb(): other side will see the updated producer. */
notify_remote_via_evtchn(xen_store_evtchn);
}
return 0;
}
int
xb_write(const void *data, unsigned len)
{
struct xenstore_domain_interface *intf = xenstore_domain_interface();
XENSTORE_RING_IDX cons, prod;
int s = spltty();
while (len != 0) {
void *dst;
unsigned int avail;
while ((intf->req_prod - intf->req_cons) == XENSTORE_RING_SIZE) {
XENPRINTF(("xb_write tsleep\n"));
tsleep(&xenstore_interface, PRIBIO, "wrst", 0);
XENPRINTF(("xb_write tsleep done\n"));
}
/* Read indexes, then verify. */
cons = intf->req_cons;
prod = intf->req_prod;
xen_rmb();
if (!check_indexes(cons, prod)) {
splx(s);
return EIO;
}
dst = get_output_chunk(cons, prod, intf->req, &avail);
if (avail == 0)
continue;
if (avail > len)
avail = len;
memcpy(dst, data, avail);
data = (const char *)data + avail;
len -= avail;
/* Other side must not see new header until data is there. */
xen_rmb();
intf->req_prod += avail;
xen_rmb();
hypervisor_notify_via_evtchn(xen_start_info.store_evtchn);
}
splx(s);
return 0;
}
