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-rw-r--r--net/sunrpc/auth_gss/gss_krb5_crypto.c2
-rw-r--r--net/sunrpc/auth_gss/svcauth_gss.c2
-rw-r--r--net/sunrpc/cache.c54
-rw-r--r--net/sunrpc/svc.c3
-rw-r--r--net/sunrpc/svc_xprt.c97
-rw-r--r--net/sunrpc/svcauth.c1
-rw-r--r--net/sunrpc/svcauth_unix.c17
-rw-r--r--net/sunrpc/svcsock.c20
-rw-r--r--net/sunrpc/xprt.c5
-rw-r--r--net/sunrpc/xprtsock.c34
10 files changed, 141 insertions, 94 deletions
diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index 75ee993ea05..9576f35ab70 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -137,7 +137,7 @@ arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4])
ms_usage = 13;
break;
default:
- return EINVAL;;
+ return -EINVAL;
}
salt[0] = (ms_usage >> 0) & 0xff;
salt[1] = (ms_usage >> 8) & 0xff;
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index dec2a6fc7c1..bcdae78fdfc 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -67,7 +67,6 @@ static int netobj_equal(struct xdr_netobj *a, struct xdr_netobj *b)
#define RSI_HASHBITS 6
#define RSI_HASHMAX (1<<RSI_HASHBITS)
-#define RSI_HASHMASK (RSI_HASHMAX-1)
struct rsi {
struct cache_head h;
@@ -319,7 +318,6 @@ static struct rsi *rsi_update(struct rsi *new, struct rsi *old)
#define RSC_HASHBITS 10
#define RSC_HASHMAX (1<<RSC_HASHBITS)
-#define RSC_HASHMASK (RSC_HASHMAX-1)
#define GSS_SEQ_WIN 128
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index e433e7580e2..72ad836e4fe 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -37,7 +37,7 @@
#define RPCDBG_FACILITY RPCDBG_CACHE
-static void cache_defer_req(struct cache_req *req, struct cache_head *item);
+static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
static void cache_revisit_request(struct cache_head *item);
static void cache_init(struct cache_head *h)
@@ -128,6 +128,7 @@ static void cache_fresh_locked(struct cache_head *head, time_t expiry)
{
head->expiry_time = expiry;
head->last_refresh = seconds_since_boot();
+ smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
set_bit(CACHE_VALID, &head->flags);
}
@@ -208,11 +209,36 @@ static inline int cache_is_valid(struct cache_detail *detail, struct cache_head
/* entry is valid */
if (test_bit(CACHE_NEGATIVE, &h->flags))
return -ENOENT;
- else
+ else {
+ /*
+ * In combination with write barrier in
+ * sunrpc_cache_update, ensures that anyone
+ * using the cache entry after this sees the
+ * updated contents:
+ */
+ smp_rmb();
return 0;
+ }
}
}
+static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h)
+{
+ int rv;
+
+ write_lock(&detail->hash_lock);
+ rv = cache_is_valid(detail, h);
+ if (rv != -EAGAIN) {
+ write_unlock(&detail->hash_lock);
+ return rv;
+ }
+ set_bit(CACHE_NEGATIVE, &h->flags);
+ cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
+ write_unlock(&detail->hash_lock);
+ cache_fresh_unlocked(h, detail);
+ return -ENOENT;
+}
+
/*
* This is the generic cache management routine for all
* the authentication caches.
@@ -251,14 +277,8 @@ int cache_check(struct cache_detail *detail,
case -EINVAL:
clear_bit(CACHE_PENDING, &h->flags);
cache_revisit_request(h);
- if (rv == -EAGAIN) {
- set_bit(CACHE_NEGATIVE, &h->flags);
- cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
- cache_fresh_unlocked(h, detail);
- rv = -ENOENT;
- }
+ rv = try_to_negate_entry(detail, h);
break;
-
case -EAGAIN:
clear_bit(CACHE_PENDING, &h->flags);
cache_revisit_request(h);
@@ -268,9 +288,11 @@ int cache_check(struct cache_detail *detail,
}
if (rv == -EAGAIN) {
- cache_defer_req(rqstp, h);
- if (!test_bit(CACHE_PENDING, &h->flags)) {
- /* Request is not deferred */
+ if (!cache_defer_req(rqstp, h)) {
+ /*
+ * Request was not deferred; handle it as best
+ * we can ourselves:
+ */
rv = cache_is_valid(detail, h);
if (rv == -EAGAIN)
rv = -ETIMEDOUT;
@@ -618,18 +640,19 @@ static void cache_limit_defers(void)
discard->revisit(discard, 1);
}
-static void cache_defer_req(struct cache_req *req, struct cache_head *item)
+/* Return true if and only if a deferred request is queued. */
+static bool cache_defer_req(struct cache_req *req, struct cache_head *item)
{
struct cache_deferred_req *dreq;
if (req->thread_wait) {
cache_wait_req(req, item);
if (!test_bit(CACHE_PENDING, &item->flags))
- return;
+ return false;
}
dreq = req->defer(req);
if (dreq == NULL)
- return;
+ return false;
setup_deferral(dreq, item, 1);
if (!test_bit(CACHE_PENDING, &item->flags))
/* Bit could have been cleared before we managed to
@@ -638,6 +661,7 @@ static void cache_defer_req(struct cache_req *req, struct cache_head *item)
cache_revisit_request(item);
cache_limit_defers();
+ return true;
}
static void cache_revisit_request(struct cache_head *item)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 0e659c665a8..08e05a8ce02 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1001,6 +1001,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
rqstp->rq_splice_ok = 1;
/* Will be turned off only when NFSv4 Sessions are used */
rqstp->rq_usedeferral = 1;
+ rqstp->rq_dropme = false;
/* Setup reply header */
rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp);
@@ -1102,7 +1103,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
*statp = procp->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
/* Encode reply */
- if (*statp == rpc_drop_reply) {
+ if (rqstp->rq_dropme) {
if (procp->pc_release)
procp->pc_release(rqstp, NULL, rqstp->rq_resp);
goto dropit;
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 3f2c5559ca1..ab86b7927f8 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -13,6 +13,7 @@
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>
#include <linux/sunrpc/svcsock.h>
+#include <linux/sunrpc/xprt.h>
#define RPCDBG_FACILITY RPCDBG_SVCXPRT
@@ -128,6 +129,9 @@ static void svc_xprt_free(struct kref *kref)
if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
svcauth_unix_info_release(xprt);
put_net(xprt->xpt_net);
+ /* See comment on corresponding get in xs_setup_bc_tcp(): */
+ if (xprt->xpt_bc_xprt)
+ xprt_put(xprt->xpt_bc_xprt);
xprt->xpt_ops->xpo_free(xprt);
module_put(owner);
}
@@ -303,6 +307,15 @@ static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
list_del(&rqstp->rq_list);
}
+static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
+{
+ if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
+ return true;
+ if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED)))
+ return xprt->xpt_ops->xpo_has_wspace(xprt);
+ return false;
+}
+
/*
* Queue up a transport with data pending. If there are idle nfsd
* processes, wake 'em up.
@@ -315,8 +328,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
struct svc_rqst *rqstp;
int cpu;
- if (!(xprt->xpt_flags &
- ((1<<XPT_CONN)|(1<<XPT_DATA)|(1<<XPT_CLOSE)|(1<<XPT_DEFERRED))))
+ if (!svc_xprt_has_something_to_do(xprt))
return;
cpu = get_cpu();
@@ -343,28 +355,7 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
dprintk("svc: transport %p busy, not enqueued\n", xprt);
goto out_unlock;
}
- BUG_ON(xprt->xpt_pool != NULL);
- xprt->xpt_pool = pool;
-
- /* Handle pending connection */
- if (test_bit(XPT_CONN, &xprt->xpt_flags))
- goto process;
-
- /* Handle close in-progress */
- if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
- goto process;
-
- /* Check if we have space to reply to a request */
- if (!xprt->xpt_ops->xpo_has_wspace(xprt)) {
- /* Don't enqueue while not enough space for reply */
- dprintk("svc: no write space, transport %p not enqueued\n",
- xprt);
- xprt->xpt_pool = NULL;
- clear_bit(XPT_BUSY, &xprt->xpt_flags);
- goto out_unlock;
- }
- process:
if (!list_empty(&pool->sp_threads)) {
rqstp = list_entry(pool->sp_threads.next,
struct svc_rqst,
@@ -381,13 +372,11 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
rqstp->rq_reserved = serv->sv_max_mesg;
atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
pool->sp_stats.threads_woken++;
- BUG_ON(xprt->xpt_pool != pool);
wake_up(&rqstp->rq_wait);
} else {
dprintk("svc: transport %p put into queue\n", xprt);
list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
pool->sp_stats.sockets_queued++;
- BUG_ON(xprt->xpt_pool != pool);
}
out_unlock:
@@ -426,7 +415,6 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
void svc_xprt_received(struct svc_xprt *xprt)
{
BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
- xprt->xpt_pool = NULL;
/* As soon as we clear busy, the xprt could be closed and
* 'put', so we need a reference to call svc_xprt_enqueue with:
*/
@@ -722,7 +710,10 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
dprintk("svc_recv: found XPT_CLOSE\n");
svc_delete_xprt(xprt);
- } else if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
+ /* Leave XPT_BUSY set on the dead xprt: */
+ goto out;
+ }
+ if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
struct svc_xprt *newxpt;
newxpt = xprt->xpt_ops->xpo_accept(xprt);
if (newxpt) {
@@ -747,28 +738,23 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
spin_unlock_bh(&serv->sv_lock);
svc_xprt_received(newxpt);
}
- svc_xprt_received(xprt);
- } else {
+ } else if (xprt->xpt_ops->xpo_has_wspace(xprt)) {
dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
rqstp, pool->sp_id, xprt,
atomic_read(&xprt->xpt_ref.refcount));
rqstp->rq_deferred = svc_deferred_dequeue(xprt);
- if (rqstp->rq_deferred) {
- svc_xprt_received(xprt);
+ if (rqstp->rq_deferred)
len = svc_deferred_recv(rqstp);
- } else {
+ else
len = xprt->xpt_ops->xpo_recvfrom(rqstp);
- svc_xprt_received(xprt);
- }
dprintk("svc: got len=%d\n", len);
}
+ svc_xprt_received(xprt);
/* No data, incomplete (TCP) read, or accept() */
- if (len == 0 || len == -EAGAIN) {
- rqstp->rq_res.len = 0;
- svc_xprt_release(rqstp);
- return -EAGAIN;
- }
+ if (len == 0 || len == -EAGAIN)
+ goto out;
+
clear_bit(XPT_OLD, &xprt->xpt_flags);
rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
@@ -777,6 +763,10 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
if (serv->sv_stats)
serv->sv_stats->netcnt++;
return len;
+out:
+ rqstp->rq_res.len = 0;
+ svc_xprt_release(rqstp);
+ return -EAGAIN;
}
EXPORT_SYMBOL_GPL(svc_recv);
@@ -935,7 +925,12 @@ void svc_close_xprt(struct svc_xprt *xprt)
if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
/* someone else will have to effect the close */
return;
-
+ /*
+ * We expect svc_close_xprt() to work even when no threads are
+ * running (e.g., while configuring the server before starting
+ * any threads), so if the transport isn't busy, we delete
+ * it ourself:
+ */
svc_delete_xprt(xprt);
}
EXPORT_SYMBOL_GPL(svc_close_xprt);
@@ -945,16 +940,16 @@ void svc_close_all(struct list_head *xprt_list)
struct svc_xprt *xprt;
struct svc_xprt *tmp;
+ /*
+ * The server is shutting down, and no more threads are running.
+ * svc_xprt_enqueue() might still be running, but at worst it
+ * will re-add the xprt to sp_sockets, which will soon get
+ * freed. So we don't bother with any more locking, and don't
+ * leave the close to the (nonexistent) server threads:
+ */
list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
set_bit(XPT_CLOSE, &xprt->xpt_flags);
- if (test_bit(XPT_BUSY, &xprt->xpt_flags)) {
- /* Waiting to be processed, but no threads left,
- * So just remove it from the waiting list
- */
- list_del_init(&xprt->xpt_ready);
- clear_bit(XPT_BUSY, &xprt->xpt_flags);
- }
- svc_close_xprt(xprt);
+ svc_delete_xprt(xprt);
}
}
@@ -1028,6 +1023,7 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
}
svc_xprt_get(rqstp->rq_xprt);
dr->xprt = rqstp->rq_xprt;
+ rqstp->rq_dropme = true;
dr->handle.revisit = svc_revisit;
return &dr->handle;
@@ -1065,14 +1061,13 @@ static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
return NULL;
spin_lock(&xprt->xpt_lock);
- clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
if (!list_empty(&xprt->xpt_deferred)) {
dr = list_entry(xprt->xpt_deferred.next,
struct svc_deferred_req,
handle.recent);
list_del_init(&dr->handle.recent);
- set_bit(XPT_DEFERRED, &xprt->xpt_flags);
- }
+ } else
+ clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
spin_unlock(&xprt->xpt_lock);
return dr;
}
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index 4e9393c2468..7963569fc04 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -118,7 +118,6 @@ EXPORT_SYMBOL_GPL(svc_auth_unregister);
#define DN_HASHBITS 6
#define DN_HASHMAX (1<<DN_HASHBITS)
-#define DN_HASHMASK (DN_HASHMAX-1)
static struct hlist_head auth_domain_table[DN_HASHMAX];
static spinlock_t auth_domain_lock =
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 560677d187f..30916b06c12 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -30,7 +30,9 @@
struct unix_domain {
struct auth_domain h;
+#ifdef CONFIG_NFSD_DEPRECATED
int addr_changes;
+#endif /* CONFIG_NFSD_DEPRECATED */
/* other stuff later */
};
@@ -64,7 +66,9 @@ struct auth_domain *unix_domain_find(char *name)
return NULL;
}
new->h.flavour = &svcauth_unix;
+#ifdef CONFIG_NFSD_DEPRECATED
new->addr_changes = 0;
+#endif /* CONFIG_NFSD_DEPRECATED */
rv = auth_domain_lookup(name, &new->h);
}
}
@@ -85,14 +89,15 @@ static void svcauth_unix_domain_release(struct auth_domain *dom)
*/
#define IP_HASHBITS 8
#define IP_HASHMAX (1<<IP_HASHBITS)
-#define IP_HASHMASK (IP_HASHMAX-1)
struct ip_map {
struct cache_head h;
char m_class[8]; /* e.g. "nfsd" */
struct in6_addr m_addr;
struct unix_domain *m_client;
+#ifdef CONFIG_NFSD_DEPRECATED
int m_add_change;
+#endif /* CONFIG_NFSD_DEPRECATED */
};
static void ip_map_put(struct kref *kref)
@@ -146,7 +151,9 @@ static void update(struct cache_head *cnew, struct cache_head *citem)
kref_get(&item->m_client->h.ref);
new->m_client = item->m_client;
+#ifdef CONFIG_NFSD_DEPRECATED
new->m_add_change = item->m_add_change;
+#endif /* CONFIG_NFSD_DEPRECATED */
}
static struct cache_head *ip_map_alloc(void)
{
@@ -331,6 +338,7 @@ static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
ip.h.flags = 0;
if (!udom)
set_bit(CACHE_NEGATIVE, &ip.h.flags);
+#ifdef CONFIG_NFSD_DEPRECATED
else {
ip.m_add_change = udom->addr_changes;
/* if this is from the legacy set_client system call,
@@ -339,6 +347,7 @@ static int __ip_map_update(struct cache_detail *cd, struct ip_map *ipm,
if (expiry == NEVER)
ip.m_add_change++;
}
+#endif /* CONFIG_NFSD_DEPRECATED */
ip.h.expiry_time = expiry;
ch = sunrpc_cache_update(cd, &ip.h, &ipm->h,
hash_str(ipm->m_class, IP_HASHBITS) ^
@@ -358,6 +367,7 @@ static inline int ip_map_update(struct net *net, struct ip_map *ipm,
return __ip_map_update(sn->ip_map_cache, ipm, udom, expiry);
}
+#ifdef CONFIG_NFSD_DEPRECATED
int auth_unix_add_addr(struct net *net, struct in6_addr *addr, struct auth_domain *dom)
{
struct unix_domain *udom;
@@ -402,8 +412,7 @@ struct auth_domain *auth_unix_lookup(struct net *net, struct in6_addr *addr)
return NULL;
if ((ipm->m_client->addr_changes - ipm->m_add_change) >0) {
- if (test_and_set_bit(CACHE_NEGATIVE, &ipm->h.flags) == 0)
- auth_domain_put(&ipm->m_client->h);
+ sunrpc_invalidate(&ipm->h, sn->ip_map_cache);
rv = NULL;
} else {
rv = &ipm->m_client->h;
@@ -413,6 +422,7 @@ struct auth_domain *auth_unix_lookup(struct net *net, struct in6_addr *addr)
return rv;
}
EXPORT_SYMBOL_GPL(auth_unix_lookup);
+#endif /* CONFIG_NFSD_DEPRECATED */
void svcauth_unix_purge(void)
{
@@ -497,7 +507,6 @@ svcauth_unix_info_release(struct svc_xprt *xpt)
*/
#define GID_HASHBITS 8
#define GID_HASHMAX (1<<GID_HASHBITS)
-#define GID_HASHMASK (GID_HASHMAX - 1)
struct unix_gid {
struct cache_head h;
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d265aa700bb..7bd3bbba471 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -331,19 +331,21 @@ int svc_sock_names(struct svc_serv *serv, char *buf, const size_t buflen,
len = onelen;
break;
}
- if (toclose && strcmp(toclose, buf + len) == 0)
+ if (toclose && strcmp(toclose, buf + len) == 0) {
closesk = svsk;
- else
+ svc_xprt_get(&closesk->sk_xprt);
+ } else
len += onelen;
}
spin_unlock_bh(&serv->sv_lock);
- if (closesk)
+ if (closesk) {
/* Should unregister with portmap, but you cannot
* unregister just one protocol...
*/
svc_close_xprt(&closesk->sk_xprt);
- else if (toclose)
+ svc_xprt_put(&closesk->sk_xprt);
+ } else if (toclose)
return -ENOENT;
return len;
}
@@ -992,15 +994,17 @@ static int svc_process_calldir(struct svc_sock *svsk, struct svc_rqst *rqstp,
vec[0] = rqstp->rq_arg.head[0];
} else {
/* REPLY */
- if (svsk->sk_bc_xprt)
- req = xprt_lookup_rqst(svsk->sk_bc_xprt, xid);
+ struct rpc_xprt *bc_xprt = svsk->sk_xprt.xpt_bc_xprt;
+
+ if (bc_xprt)
+ req = xprt_lookup_rqst(bc_xprt, xid);
if (!req) {
printk(KERN_NOTICE
"%s: Got unrecognized reply: "
- "calldir 0x%x sk_bc_xprt %p xid %08x\n",
+ "calldir 0x%x xpt_bc_xprt %p xid %08x\n",
__func__, ntohl(calldir),
- svsk->sk_bc_xprt, xid);
+ bc_xprt, xid);
vec[0] = rqstp->rq_arg.head[0];
goto out;
}
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 4c8f18aff7c..856274d7e85 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -965,6 +965,7 @@ struct rpc_xprt *xprt_alloc(struct net *net, int size, int max_req)
xprt = kzalloc(size, GFP_KERNEL);
if (xprt == NULL)
goto out;
+ kref_init(&xprt->kref);
xprt->max_reqs = max_req;
xprt->slot = kcalloc(max_req, sizeof(struct rpc_rqst), GFP_KERNEL);
@@ -1101,8 +1102,10 @@ found:
-PTR_ERR(xprt));
return xprt;
}
+ if (test_and_set_bit(XPRT_INITIALIZED, &xprt->state))
+ /* ->setup returned a pre-initialized xprt: */
+ return xprt;
- kref_init(&xprt->kref);
spin_lock_init(&xprt->transport_lock);
spin_lock_init(&xprt->reserve_lock);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 96549df836e..c431f5a5796 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2359,6 +2359,15 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
struct svc_sock *bc_sock;
struct rpc_xprt *ret;
+ if (args->bc_xprt->xpt_bc_xprt) {
+ /*
+ * This server connection already has a backchannel
+ * export; we can't create a new one, as we wouldn't be
+ * able to match replies based on xid any more. So,
+ * reuse the already-existing one:
+ */
+ return args->bc_xprt->xpt_bc_xprt;
+ }
xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
if (IS_ERR(xprt))
return xprt;
@@ -2375,16 +2384,6 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
xprt->reestablish_timeout = 0;
xprt->idle_timeout = 0;
- /*
- * The backchannel uses the same socket connection as the
- * forechannel
- */
- xprt->bc_xprt = args->bc_xprt;
- bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
- bc_sock->sk_bc_xprt = xprt;
- transport->sock = bc_sock->sk_sock;
- transport->inet = bc_sock->sk_sk;
-
xprt->ops = &bc_tcp_ops;
switch (addr->sa_family) {
@@ -2407,6 +2406,20 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
xprt->address_strings[RPC_DISPLAY_PROTO]);
/*
+ * Once we've associated a backchannel xprt with a connection,
+ * we want to keep it around as long as long as the connection
+ * lasts, in case we need to start using it for a backchannel
+ * again; this reference won't be dropped until bc_xprt is
+ * destroyed.
+ */
+ xprt_get(xprt);
+ args->bc_xprt->xpt_bc_xprt = xprt;
+ xprt->bc_xprt = args->bc_xprt;
+ bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
+ transport->sock = bc_sock->sk_sock;
+ transport->inet = bc_sock->sk_sk;
+
+ /*
* Since we don't want connections for the backchannel, we set
* the xprt status to connected
*/
@@ -2415,6 +2428,7 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
if (try_module_get(THIS_MODULE))
return xprt;
+ xprt_put(xprt);
ret = ERR_PTR(-EINVAL);
out_err:
xprt_free(xprt);