sunrpc: don't wait for write before allowing reads from use-gss-proxy file

It doesn't make much sense to make reads from this procfile hang. As
far as I can tell, only gssproxy itself will open this file and it
never reads from it. Change it to just give the present setting of
sn->use_gss_proxy without waiting for anything.

Note that we do not want to call use_gss_proxy() in this codepath
since an inopportune read of this file could cause it to be disabled
prematurely.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/net/sunrpc/auth_gss/gss_rpc_upcall.c b/net/sunrpc/auth_gss/gss_rpc_upcall.c
index 458f85e..abbb7dc 100644 (file)
--- a/net/sunrpc/auth_gss/gss_rpc_upcall.c
+++ b/net/sunrpc/auth_gss/gss_rpc_upcall.c
@@ -137,7 +137,6 @@ void init_gssp_clnt(struct sunrpc_net *sn)
 {
        mutex_init(&sn->gssp_lock);
        sn->gssp_clnt = NULL;
-       init_waitqueue_head(&sn->gssp_wq);
 }
 
 int set_gssp_clnt(struct net *net)
@@ -154,7 +153,6 @@ int set_gssp_clnt(struct net *net)
                sn->gssp_clnt = clnt;
        }
        mutex_unlock(&sn->gssp_lock);
-       wake_up(&sn->gssp_wq);
        return ret;
 }
 

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 008cdad..1b94a9c 100644 (file)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1295,34 +1295,9 @@ static int set_gss_proxy(struct net *net, int type)
        else
                ret = -EBUSY;
        spin_unlock(&use_gssp_lock);
-       wake_up(&sn->gssp_wq);
        return ret;
 }
 
-static inline bool gssp_ready(struct sunrpc_net *sn)
-{
-       switch (sn->use_gss_proxy) {
-               case -1:
-                       return false;
-               case 0:
-                       return true;
-               case 1:
-                       return sn->gssp_clnt;
-       }
-       WARN_ON_ONCE(1);
-       return false;
-}
-
-static int wait_for_gss_proxy(struct net *net, struct file *file)
-{
-       struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
-
-       if (file->f_flags & O_NONBLOCK && !gssp_ready(sn))
-               return -EAGAIN;
-       return wait_event_interruptible(sn->gssp_wq, gssp_ready(sn));
-}
-
-
 static ssize_t write_gssp(struct file *file, const char __user *buf,
                         size_t count, loff_t *ppos)
 {
@@ -1355,16 +1330,12 @@ static ssize_t read_gssp(struct file *file, char __user *buf,
                         size_t count, loff_t *ppos)
 {
        struct net *net = PDE_DATA(file_inode(file));
+       struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
        unsigned long p = *ppos;
        char tbuf[10];
        size_t len;
-       int ret;
-
-       ret = wait_for_gss_proxy(net, file);
-       if (ret)
-               return ret;
 
-       snprintf(tbuf, sizeof(tbuf), "%d\n", use_gss_proxy(net));
+       snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
        len = strlen(tbuf);
        if (p >= len)
                return 0;

diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h
index 779742c..3a260e4 100644 (file)
--- a/net/sunrpc/netns.h
+++ b/net/sunrpc/netns.h
@@ -26,7 +26,6 @@ struct sunrpc_net {
        unsigned int rpcb_is_af_local : 1;
 
        struct mutex gssp_lock;
-       wait_queue_head_t gssp_wq;
        struct rpc_clnt *gssp_clnt;
        int use_gss_proxy;
        int pipe_version;