linux/net/rxrpc/ar-connection.c
Mel Gorman d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00

929 lines
23 KiB
C

/* RxRPC virtual connection handler
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
/*
* Time till a connection expires after last use (in seconds).
*/
unsigned rxrpc_connection_expiry = 10 * 60;
static void rxrpc_connection_reaper(struct work_struct *work);
LIST_HEAD(rxrpc_connections);
DEFINE_RWLOCK(rxrpc_connection_lock);
static DECLARE_DELAYED_WORK(rxrpc_connection_reap, rxrpc_connection_reaper);
/*
* allocate a new client connection bundle
*/
static struct rxrpc_conn_bundle *rxrpc_alloc_bundle(gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle;
_enter("");
bundle = kzalloc(sizeof(struct rxrpc_conn_bundle), gfp);
if (bundle) {
INIT_LIST_HEAD(&bundle->unused_conns);
INIT_LIST_HEAD(&bundle->avail_conns);
INIT_LIST_HEAD(&bundle->busy_conns);
init_waitqueue_head(&bundle->chanwait);
atomic_set(&bundle->usage, 1);
}
_leave(" = %p", bundle);
return bundle;
}
/*
* compare bundle parameters with what we're looking for
* - return -ve, 0 or +ve
*/
static inline
int rxrpc_cmp_bundle(const struct rxrpc_conn_bundle *bundle,
struct key *key, __be16 service_id)
{
return (bundle->service_id - service_id) ?:
((unsigned long) bundle->key - (unsigned long) key);
}
/*
* get bundle of client connections that a client socket can make use of
*/
struct rxrpc_conn_bundle *rxrpc_get_bundle(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
struct key *key,
__be16 service_id,
gfp_t gfp)
{
struct rxrpc_conn_bundle *bundle, *candidate;
struct rb_node *p, *parent, **pp;
_enter("%p{%x},%x,%hx,",
rx, key_serial(key), trans->debug_id, ntohs(service_id));
if (rx->trans == trans && rx->bundle) {
atomic_inc(&rx->bundle->usage);
return rx->bundle;
}
/* search the extant bundles first for one that matches the specified
* user ID */
spin_lock(&trans->client_lock);
p = trans->bundles.rb_node;
while (p) {
bundle = rb_entry(p, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
p = p->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
p = p->rb_right;
else
goto found_extant_bundle;
}
spin_unlock(&trans->client_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_bundle(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->key = key_get(key);
candidate->service_id = service_id;
spin_lock(&trans->client_lock);
pp = &trans->bundles.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
bundle = rb_entry(parent, struct rxrpc_conn_bundle, node);
if (rxrpc_cmp_bundle(bundle, key, service_id) < 0)
pp = &(*pp)->rb_left;
else if (rxrpc_cmp_bundle(bundle, key, service_id) > 0)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* second search also failed; add the new bundle */
bundle = candidate;
candidate = NULL;
rb_link_node(&bundle->node, parent, pp);
rb_insert_color(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
_net("BUNDLE new on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [new]", bundle);
return bundle;
/* we found the bundle in the list immediately */
found_extant_bundle:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
_net("BUNDLE old on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [extant %d]", bundle, atomic_read(&bundle->usage));
return bundle;
/* we found the bundle on the second time through the list */
found_extant_second:
atomic_inc(&bundle->usage);
spin_unlock(&trans->client_lock);
kfree(candidate);
_net("BUNDLE old2 on trans %d", trans->debug_id);
if (!rx->bundle && rx->sk.sk_state == RXRPC_CLIENT_CONNECTED) {
atomic_inc(&bundle->usage);
rx->bundle = bundle;
}
_leave(" = %p [second %d]", bundle, atomic_read(&bundle->usage));
return bundle;
}
/*
* release a bundle
*/
void rxrpc_put_bundle(struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle)
{
_enter("%p,%p{%d}",trans, bundle, atomic_read(&bundle->usage));
if (atomic_dec_and_lock(&bundle->usage, &trans->client_lock)) {
_debug("Destroy bundle");
rb_erase(&bundle->node, &trans->bundles);
spin_unlock(&trans->client_lock);
ASSERT(list_empty(&bundle->unused_conns));
ASSERT(list_empty(&bundle->avail_conns));
ASSERT(list_empty(&bundle->busy_conns));
ASSERTCMP(bundle->num_conns, ==, 0);
key_put(bundle->key);
kfree(bundle);
}
_leave("");
}
/*
* allocate a new connection
*/
static struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
{
struct rxrpc_connection *conn;
_enter("");
conn = kzalloc(sizeof(struct rxrpc_connection), gfp);
if (conn) {
INIT_WORK(&conn->processor, &rxrpc_process_connection);
INIT_LIST_HEAD(&conn->bundle_link);
conn->calls = RB_ROOT;
skb_queue_head_init(&conn->rx_queue);
rwlock_init(&conn->lock);
spin_lock_init(&conn->state_lock);
atomic_set(&conn->usage, 1);
conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
conn->avail_calls = RXRPC_MAXCALLS;
conn->size_align = 4;
conn->header_size = sizeof(struct rxrpc_header);
}
_leave(" = %p{%d}", conn, conn ? conn->debug_id : 0);
return conn;
}
/*
* assign a connection ID to a connection and add it to the transport's
* connection lookup tree
* - called with transport client lock held
*/
static void rxrpc_assign_connection_id(struct rxrpc_connection *conn)
{
struct rxrpc_connection *xconn;
struct rb_node *parent, **p;
__be32 epoch;
u32 real_conn_id;
_enter("");
epoch = conn->epoch;
write_lock_bh(&conn->trans->conn_lock);
conn->trans->conn_idcounter += RXRPC_CID_INC;
if (conn->trans->conn_idcounter < RXRPC_CID_INC)
conn->trans->conn_idcounter = RXRPC_CID_INC;
real_conn_id = conn->trans->conn_idcounter;
attempt_insertion:
parent = NULL;
p = &conn->trans->client_conns.rb_node;
while (*p) {
parent = *p;
xconn = rb_entry(parent, struct rxrpc_connection, node);
if (epoch < xconn->epoch)
p = &(*p)->rb_left;
else if (epoch > xconn->epoch)
p = &(*p)->rb_right;
else if (real_conn_id < xconn->real_conn_id)
p = &(*p)->rb_left;
else if (real_conn_id > xconn->real_conn_id)
p = &(*p)->rb_right;
else
goto id_exists;
}
/* we've found a suitable hole - arrange for this connection to occupy
* it */
rb_link_node(&conn->node, parent, p);
rb_insert_color(&conn->node, &conn->trans->client_conns);
conn->real_conn_id = real_conn_id;
conn->cid = htonl(real_conn_id);
write_unlock_bh(&conn->trans->conn_lock);
_leave(" [CONNID %x CID %x]", real_conn_id, ntohl(conn->cid));
return;
/* we found a connection with the proposed ID - walk the tree from that
* point looking for the next unused ID */
id_exists:
for (;;) {
real_conn_id += RXRPC_CID_INC;
if (real_conn_id < RXRPC_CID_INC) {
real_conn_id = RXRPC_CID_INC;
conn->trans->conn_idcounter = real_conn_id;
goto attempt_insertion;
}
parent = rb_next(parent);
if (!parent)
goto attempt_insertion;
xconn = rb_entry(parent, struct rxrpc_connection, node);
if (epoch < xconn->epoch ||
real_conn_id < xconn->real_conn_id)
goto attempt_insertion;
}
}
/*
* add a call to a connection's call-by-ID tree
*/
static void rxrpc_add_call_ID_to_conn(struct rxrpc_connection *conn,
struct rxrpc_call *call)
{
struct rxrpc_call *xcall;
struct rb_node *parent, **p;
__be32 call_id;
write_lock_bh(&conn->lock);
call_id = call->call_id;
p = &conn->calls.rb_node;
parent = NULL;
while (*p) {
parent = *p;
xcall = rb_entry(parent, struct rxrpc_call, conn_node);
if (call_id < xcall->call_id)
p = &(*p)->rb_left;
else if (call_id > xcall->call_id)
p = &(*p)->rb_right;
else
BUG();
}
rb_link_node(&call->conn_node, parent, p);
rb_insert_color(&call->conn_node, &conn->calls);
write_unlock_bh(&conn->lock);
}
/*
* connect a call on an exclusive connection
*/
static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
__be16 service_id,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn;
int chan, ret;
_enter("");
conn = rx->conn;
if (!conn) {
/* not yet present - create a candidate for a new connection
* and then redo the check */
conn = rxrpc_alloc_connection(gfp);
if (!conn) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
conn->trans = trans;
conn->bundle = NULL;
conn->service_id = service_id;
conn->epoch = rxrpc_epoch;
conn->in_clientflag = 0;
conn->out_clientflag = RXRPC_CLIENT_INITIATED;
conn->cid = 0;
conn->state = RXRPC_CONN_CLIENT;
conn->avail_calls = RXRPC_MAXCALLS - 1;
conn->security_level = rx->min_sec_level;
conn->key = key_get(rx->key);
ret = rxrpc_init_client_conn_security(conn);
if (ret < 0) {
key_put(conn->key);
kfree(conn);
_leave(" = %d [key]", ret);
return ret;
}
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
spin_lock(&trans->client_lock);
atomic_inc(&trans->usage);
_net("CONNECT EXCL new %d on TRANS %d",
conn->debug_id, conn->trans->debug_id);
rxrpc_assign_connection_id(conn);
rx->conn = conn;
} else {
spin_lock(&trans->client_lock);
}
/* we've got a connection with a free channel and we can now attach the
* call to it
* - we're holding the transport's client lock
* - we're holding a reference on the connection
*/
for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
if (!conn->channels[chan])
goto found_channel;
goto no_free_channels;
found_channel:
atomic_inc(&conn->usage);
conn->channels[chan] = call;
call->conn = conn;
call->channel = chan;
call->cid = conn->cid | htonl(chan);
call->call_id = htonl(++conn->call_counter);
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, ntohl(call->call_id));
spin_unlock(&trans->client_lock);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
no_free_channels:
spin_unlock(&trans->client_lock);
_leave(" = -ENOSR");
return -ENOSR;
}
/*
* find a connection for a call
* - called in process context with IRQs enabled
*/
int rxrpc_connect_call(struct rxrpc_sock *rx,
struct rxrpc_transport *trans,
struct rxrpc_conn_bundle *bundle,
struct rxrpc_call *call,
gfp_t gfp)
{
struct rxrpc_connection *conn, *candidate;
int chan, ret;
DECLARE_WAITQUEUE(myself, current);
_enter("%p,%lx,", rx, call->user_call_ID);
if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
return rxrpc_connect_exclusive(rx, trans, bundle->service_id,
call, gfp);
spin_lock(&trans->client_lock);
for (;;) {
/* see if the bundle has a call slot available */
if (!list_empty(&bundle->avail_conns)) {
_debug("avail");
conn = list_entry(bundle->avail_conns.next,
struct rxrpc_connection,
bundle_link);
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
list_del_init(&conn->bundle_link);
bundle->num_conns--;
continue;
}
if (--conn->avail_calls == 0)
list_move(&conn->bundle_link,
&bundle->busy_conns);
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
atomic_inc(&conn->usage);
break;
}
if (!list_empty(&bundle->unused_conns)) {
_debug("unused");
conn = list_entry(bundle->unused_conns.next,
struct rxrpc_connection,
bundle_link);
if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
list_del_init(&conn->bundle_link);
bundle->num_conns--;
continue;
}
ASSERTCMP(conn->avail_calls, ==, RXRPC_MAXCALLS);
conn->avail_calls = RXRPC_MAXCALLS - 1;
ASSERT(conn->channels[0] == NULL &&
conn->channels[1] == NULL &&
conn->channels[2] == NULL &&
conn->channels[3] == NULL);
atomic_inc(&conn->usage);
list_move(&conn->bundle_link, &bundle->avail_conns);
break;
}
/* need to allocate a new connection */
_debug("get new conn [%d]", bundle->num_conns);
spin_unlock(&trans->client_lock);
if (signal_pending(current))
goto interrupted;
if (bundle->num_conns >= 20) {
_debug("too many conns");
if (!gfpflags_allow_blocking(gfp)) {
_leave(" = -EAGAIN");
return -EAGAIN;
}
add_wait_queue(&bundle->chanwait, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (bundle->num_conns < 20 ||
!list_empty(&bundle->unused_conns) ||
!list_empty(&bundle->avail_conns))
break;
if (signal_pending(current))
goto interrupted_dequeue;
schedule();
}
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
spin_lock(&trans->client_lock);
continue;
}
/* not yet present - create a candidate for a new connection and then
* redo the check */
candidate = rxrpc_alloc_connection(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return -ENOMEM;
}
candidate->trans = trans;
candidate->bundle = bundle;
candidate->service_id = bundle->service_id;
candidate->epoch = rxrpc_epoch;
candidate->in_clientflag = 0;
candidate->out_clientflag = RXRPC_CLIENT_INITIATED;
candidate->cid = 0;
candidate->state = RXRPC_CONN_CLIENT;
candidate->avail_calls = RXRPC_MAXCALLS;
candidate->security_level = rx->min_sec_level;
candidate->key = key_get(bundle->key);
ret = rxrpc_init_client_conn_security(candidate);
if (ret < 0) {
key_put(candidate->key);
kfree(candidate);
_leave(" = %d [key]", ret);
return ret;
}
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&candidate->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
spin_lock(&trans->client_lock);
list_add(&candidate->bundle_link, &bundle->unused_conns);
bundle->num_conns++;
atomic_inc(&bundle->usage);
atomic_inc(&trans->usage);
_net("CONNECT new %d on TRANS %d",
candidate->debug_id, candidate->trans->debug_id);
rxrpc_assign_connection_id(candidate);
if (candidate->security)
candidate->security->prime_packet_security(candidate);
/* leave the candidate lurking in zombie mode attached to the
* bundle until we're ready for it */
rxrpc_put_connection(candidate);
candidate = NULL;
}
/* we've got a connection with a free channel and we can now attach the
* call to it
* - we're holding the transport's client lock
* - we're holding a reference on the connection
* - we're holding a reference on the bundle
*/
for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
if (!conn->channels[chan])
goto found_channel;
ASSERT(conn->channels[0] == NULL ||
conn->channels[1] == NULL ||
conn->channels[2] == NULL ||
conn->channels[3] == NULL);
BUG();
found_channel:
conn->channels[chan] = call;
call->conn = conn;
call->channel = chan;
call->cid = conn->cid | htonl(chan);
call->call_id = htonl(++conn->call_counter);
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, ntohl(call->call_id));
ASSERTCMP(conn->avail_calls, <, RXRPC_MAXCALLS);
spin_unlock(&trans->client_lock);
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
interrupted_dequeue:
remove_wait_queue(&bundle->chanwait, &myself);
__set_current_state(TASK_RUNNING);
interrupted:
_leave(" = -ERESTARTSYS");
return -ERESTARTSYS;
}
/*
* get a record of an incoming connection
*/
struct rxrpc_connection *
rxrpc_incoming_connection(struct rxrpc_transport *trans,
struct rxrpc_header *hdr,
gfp_t gfp)
{
struct rxrpc_connection *conn, *candidate = NULL;
struct rb_node *p, **pp;
const char *new = "old";
__be32 epoch;
u32 conn_id;
_enter("");
ASSERT(hdr->flags & RXRPC_CLIENT_INITIATED);
epoch = hdr->epoch;
conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
/* search the connection list first */
read_lock_bh(&trans->conn_lock);
p = trans->server_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->real_conn_id);
if (epoch < conn->epoch)
p = p->rb_left;
else if (epoch > conn->epoch)
p = p->rb_right;
else if (conn_id < conn->real_conn_id)
p = p->rb_left;
else if (conn_id > conn->real_conn_id)
p = p->rb_right;
else
goto found_extant_connection;
}
read_unlock_bh(&trans->conn_lock);
/* not yet present - create a candidate for a new record and then
* redo the search */
candidate = rxrpc_alloc_connection(gfp);
if (!candidate) {
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
candidate->trans = trans;
candidate->epoch = hdr->epoch;
candidate->cid = hdr->cid & cpu_to_be32(RXRPC_CIDMASK);
candidate->service_id = hdr->serviceId;
candidate->security_ix = hdr->securityIndex;
candidate->in_clientflag = RXRPC_CLIENT_INITIATED;
candidate->out_clientflag = 0;
candidate->real_conn_id = conn_id;
candidate->state = RXRPC_CONN_SERVER;
if (candidate->service_id)
candidate->state = RXRPC_CONN_SERVER_UNSECURED;
write_lock_bh(&trans->conn_lock);
pp = &trans->server_conns.rb_node;
p = NULL;
while (*pp) {
p = *pp;
conn = rb_entry(p, struct rxrpc_connection, node);
if (epoch < conn->epoch)
pp = &(*pp)->rb_left;
else if (epoch > conn->epoch)
pp = &(*pp)->rb_right;
else if (conn_id < conn->real_conn_id)
pp = &(*pp)->rb_left;
else if (conn_id > conn->real_conn_id)
pp = &(*pp)->rb_right;
else
goto found_extant_second;
}
/* we can now add the new candidate to the list */
conn = candidate;
candidate = NULL;
rb_link_node(&conn->node, p, pp);
rb_insert_color(&conn->node, &trans->server_conns);
atomic_inc(&conn->trans->usage);
write_unlock_bh(&trans->conn_lock);
write_lock_bh(&rxrpc_connection_lock);
list_add_tail(&conn->link, &rxrpc_connections);
write_unlock_bh(&rxrpc_connection_lock);
new = "new";
success:
_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->real_conn_id);
_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
return conn;
/* we found the connection in the list immediately */
found_extant_connection:
if (hdr->securityIndex != conn->security_ix) {
read_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
atomic_inc(&conn->usage);
read_unlock_bh(&trans->conn_lock);
goto success;
/* we found the connection on the second time through the list */
found_extant_second:
if (hdr->securityIndex != conn->security_ix) {
write_unlock_bh(&trans->conn_lock);
goto security_mismatch;
}
atomic_inc(&conn->usage);
write_unlock_bh(&trans->conn_lock);
kfree(candidate);
goto success;
security_mismatch:
kfree(candidate);
_leave(" = -EKEYREJECTED");
return ERR_PTR(-EKEYREJECTED);
}
/*
* find a connection based on transport and RxRPC connection ID for an incoming
* packet
*/
struct rxrpc_connection *rxrpc_find_connection(struct rxrpc_transport *trans,
struct rxrpc_header *hdr)
{
struct rxrpc_connection *conn;
struct rb_node *p;
__be32 epoch;
u32 conn_id;
_enter(",{%x,%x}", ntohl(hdr->cid), hdr->flags);
read_lock_bh(&trans->conn_lock);
conn_id = ntohl(hdr->cid) & RXRPC_CIDMASK;
epoch = hdr->epoch;
if (hdr->flags & RXRPC_CLIENT_INITIATED)
p = trans->server_conns.rb_node;
else
p = trans->client_conns.rb_node;
while (p) {
conn = rb_entry(p, struct rxrpc_connection, node);
_debug("maybe %x", conn->real_conn_id);
if (epoch < conn->epoch)
p = p->rb_left;
else if (epoch > conn->epoch)
p = p->rb_right;
else if (conn_id < conn->real_conn_id)
p = p->rb_left;
else if (conn_id > conn->real_conn_id)
p = p->rb_right;
else
goto found;
}
read_unlock_bh(&trans->conn_lock);
_leave(" = NULL");
return NULL;
found:
atomic_inc(&conn->usage);
read_unlock_bh(&trans->conn_lock);
_leave(" = %p", conn);
return conn;
}
/*
* release a virtual connection
*/
void rxrpc_put_connection(struct rxrpc_connection *conn)
{
_enter("%p{u=%d,d=%d}",
conn, atomic_read(&conn->usage), conn->debug_id);
ASSERTCMP(atomic_read(&conn->usage), >, 0);
conn->put_time = ktime_get_seconds();
if (atomic_dec_and_test(&conn->usage)) {
_debug("zombie");
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
}
_leave("");
}
/*
* destroy a virtual connection
*/
static void rxrpc_destroy_connection(struct rxrpc_connection *conn)
{
_enter("%p{%d}", conn, atomic_read(&conn->usage));
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
_net("DESTROY CONN %d", conn->debug_id);
if (conn->bundle)
rxrpc_put_bundle(conn->trans, conn->bundle);
ASSERT(RB_EMPTY_ROOT(&conn->calls));
rxrpc_purge_queue(&conn->rx_queue);
rxrpc_clear_conn_security(conn);
rxrpc_put_transport(conn->trans);
kfree(conn);
_leave("");
}
/*
* reap dead connections
*/
static void rxrpc_connection_reaper(struct work_struct *work)
{
struct rxrpc_connection *conn, *_p;
unsigned long now, earliest, reap_time;
LIST_HEAD(graveyard);
_enter("");
now = ktime_get_seconds();
earliest = ULONG_MAX;
write_lock_bh(&rxrpc_connection_lock);
list_for_each_entry_safe(conn, _p, &rxrpc_connections, link) {
_debug("reap CONN %d { u=%d,t=%ld }",
conn->debug_id, atomic_read(&conn->usage),
(long) now - (long) conn->put_time);
if (likely(atomic_read(&conn->usage) > 0))
continue;
spin_lock(&conn->trans->client_lock);
write_lock(&conn->trans->conn_lock);
reap_time = conn->put_time + rxrpc_connection_expiry;
if (atomic_read(&conn->usage) > 0) {
;
} else if (reap_time <= now) {
list_move_tail(&conn->link, &graveyard);
if (conn->out_clientflag)
rb_erase(&conn->node,
&conn->trans->client_conns);
else
rb_erase(&conn->node,
&conn->trans->server_conns);
if (conn->bundle) {
list_del_init(&conn->bundle_link);
conn->bundle->num_conns--;
}
} else if (reap_time < earliest) {
earliest = reap_time;
}
write_unlock(&conn->trans->conn_lock);
spin_unlock(&conn->trans->client_lock);
}
write_unlock_bh(&rxrpc_connection_lock);
if (earliest != ULONG_MAX) {
_debug("reschedule reaper %ld", (long) earliest - now);
ASSERTCMP(earliest, >, now);
rxrpc_queue_delayed_work(&rxrpc_connection_reap,
(earliest - now) * HZ);
}
/* then destroy all those pulled out */
while (!list_empty(&graveyard)) {
conn = list_entry(graveyard.next, struct rxrpc_connection,
link);
list_del_init(&conn->link);
ASSERTCMP(atomic_read(&conn->usage), ==, 0);
rxrpc_destroy_connection(conn);
}
_leave("");
}
/*
* preemptively destroy all the connection records rather than waiting for them
* to time out
*/
void __exit rxrpc_destroy_all_connections(void)
{
_enter("");
rxrpc_connection_expiry = 0;
cancel_delayed_work(&rxrpc_connection_reap);
rxrpc_queue_delayed_work(&rxrpc_connection_reap, 0);
_leave("");
}