// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS vlserver probing
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*
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* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include "afs_fs.h"
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#include "internal.h"
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#include "protocol_yfs.h"
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/*
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* Handle the completion of a set of probes.
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*/
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static void afs_finished_vl_probe(struct afs_vlserver *server)
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{
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if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
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server->rtt = UINT_MAX;
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clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
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}
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clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);
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wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);
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}
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/*
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* Handle the completion of a probe RPC call.
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*/
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static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)
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{
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if (atomic_dec_and_test(&server->probe_outstanding)) {
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afs_finished_vl_probe(server);
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wake_up = true;
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}
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if (wake_up)
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wake_up_all(&server->probe_wq);
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}
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/*
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* Process the result of probing a vlserver. This is called after successful
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* or failed delivery of an VL.GetCapabilities operation.
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*/
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void afs_vlserver_probe_result(struct afs_call *call)
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{
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struct afs_addr_list *alist = call->alist;
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struct afs_vlserver *server = call->vlserver;
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unsigned int server_index = call->server_index;
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unsigned int rtt_us = 0;
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unsigned int index = call->addr_ix;
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bool have_result = false;
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int ret = call->error;
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_enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);
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spin_lock(&server->probe_lock);
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switch (ret) {
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case 0:
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server->probe.error = 0;
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goto responded;
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case -ECONNABORTED:
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if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
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server->probe.abort_code = call->abort_code;
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server->probe.error = ret;
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}
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goto responded;
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case -ENOMEM:
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case -ENONET:
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case -EKEYEXPIRED:
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case -EKEYREVOKED:
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case -EKEYREJECTED:
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server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;
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if (server->probe.error == 0)
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server->probe.error = ret;
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trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
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goto out;
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case -ECONNRESET: /* Responded, but call expired. */
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case -ERFKILL:
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case -EADDRNOTAVAIL:
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case -ENETUNREACH:
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case -EHOSTUNREACH:
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case -EHOSTDOWN:
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case -ECONNREFUSED:
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case -ETIMEDOUT:
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case -ETIME:
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default:
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clear_bit(index, &alist->responded);
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set_bit(index, &alist->failed);
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if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&
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(server->probe.error == 0 ||
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server->probe.error == -ETIMEDOUT ||
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server->probe.error == -ETIME))
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server->probe.error = ret;
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trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
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goto out;
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}
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responded:
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set_bit(index, &alist->responded);
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clear_bit(index, &alist->failed);
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if (call->service_id == YFS_VL_SERVICE) {
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server->probe.flags |= AFS_VLSERVER_PROBE_IS_YFS;
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set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
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alist->addrs[index].srx_service = call->service_id;
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} else {
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server->probe.flags |= AFS_VLSERVER_PROBE_NOT_YFS;
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if (!(server->probe.flags & AFS_VLSERVER_PROBE_IS_YFS)) {
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clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
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alist->addrs[index].srx_service = call->service_id;
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}
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}
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if (rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us) &&
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rtt_us < server->probe.rtt) {
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server->probe.rtt = rtt_us;
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server->rtt = rtt_us;
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alist->preferred = index;
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}
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smp_wmb(); /* Set rtt before responded. */
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server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;
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set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
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set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
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have_result = true;
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out:
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spin_unlock(&server->probe_lock);
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_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
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server_index, index, &alist->addrs[index].transport, rtt_us, ret);
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afs_done_one_vl_probe(server, have_result);
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}
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/*
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* Probe all of a vlserver's addresses to find out the best route and to
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* query its capabilities.
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*/
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static bool afs_do_probe_vlserver(struct afs_net *net,
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struct afs_vlserver *server,
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struct key *key,
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unsigned int server_index,
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struct afs_error *_e)
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{
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struct afs_addr_cursor ac = {
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.index = 0,
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};
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struct afs_call *call;
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bool in_progress = false;
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_enter("%s", server->name);
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read_lock(&server->lock);
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ac.alist = rcu_dereference_protected(server->addresses,
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lockdep_is_held(&server->lock));
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read_unlock(&server->lock);
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atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
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memset(&server->probe, 0, sizeof(server->probe));
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server->probe.rtt = UINT_MAX;
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for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
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call = afs_vl_get_capabilities(net, &ac, key, server,
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server_index);
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if (!IS_ERR(call)) {
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afs_put_call(call);
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in_progress = true;
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} else {
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afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
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afs_done_one_vl_probe(server, false);
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}
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}
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return in_progress;
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}
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/*
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* Send off probes to all unprobed servers.
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*/
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int afs_send_vl_probes(struct afs_net *net, struct key *key,
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struct afs_vlserver_list *vllist)
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{
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struct afs_vlserver *server;
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struct afs_error e;
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bool in_progress = false;
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int i;
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e.error = 0;
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e.responded = false;
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for (i = 0; i < vllist->nr_servers; i++) {
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server = vllist->servers[i].server;
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if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))
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continue;
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if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&
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afs_do_probe_vlserver(net, server, key, i, &e))
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in_progress = true;
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}
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return in_progress ? 0 : e.error;
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}
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/*
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* Wait for the first as-yet untried server to respond.
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*/
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int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
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unsigned long untried)
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{
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struct wait_queue_entry *waits;
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struct afs_vlserver *server;
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unsigned int rtt = UINT_MAX, rtt_s;
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bool have_responders = false;
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int pref = -1, i;
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_enter("%u,%lx", vllist->nr_servers, untried);
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/* Only wait for servers that have a probe outstanding. */
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for (i = 0; i < vllist->nr_servers; i++) {
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if (test_bit(i, &untried)) {
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server = vllist->servers[i].server;
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if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
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__clear_bit(i, &untried);
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if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
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have_responders = true;
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}
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}
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if (have_responders || !untried)
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return 0;
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waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL);
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if (!waits)
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return -ENOMEM;
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for (i = 0; i < vllist->nr_servers; i++) {
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if (test_bit(i, &untried)) {
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server = vllist->servers[i].server;
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init_waitqueue_entry(&waits[i], current);
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add_wait_queue(&server->probe_wq, &waits[i]);
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}
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}
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for (;;) {
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bool still_probing = false;
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set_current_state(TASK_INTERRUPTIBLE);
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for (i = 0; i < vllist->nr_servers; i++) {
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if (test_bit(i, &untried)) {
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server = vllist->servers[i].server;
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if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
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goto stop;
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if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
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still_probing = true;
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}
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}
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if (!still_probing || signal_pending(current))
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goto stop;
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schedule();
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}
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stop:
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set_current_state(TASK_RUNNING);
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for (i = 0; i < vllist->nr_servers; i++) {
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if (test_bit(i, &untried)) {
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server = vllist->servers[i].server;
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rtt_s = READ_ONCE(server->rtt);
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if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&
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rtt_s < rtt) {
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pref = i;
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rtt = rtt_s;
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}
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remove_wait_queue(&server->probe_wq, &waits[i]);
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}
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}
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kfree(waits);
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if (pref == -1 && signal_pending(current))
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return -ERESTARTSYS;
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if (pref >= 0)
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vllist->preferred = pref;
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_leave(" = 0 [%u]", pref);
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return 0;
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}
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