svc: Add /proc/sys/sunrpc/transport files

Add a file that when read lists the set of registered svc
transports.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 31 insertions, 0 deletions

diff --git a/net/sunrpc/sysctl.c b/net/sunrpc/sysctl.c
index bada7de0c2fc..0f8c439b848a 100644
--- a/net/sunrpc/sysctl.c
+++ b/net/sunrpc/sysctl.c
@@ -18,6 +18,7 @@
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/sched.h>
 #include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/svc_xprt.h>
 
 /*
  * Declare the debug flags here
@@ -55,6 +56,30 @@ rpc_unregister_sysctl(void)
         }
 }
 
+static int proc_do_xprt(ctl_table *table, int write, struct file *file,
+                        void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        char tmpbuf[256];
+        int len;
+        if ((*ppos && !write) || !*lenp) {
+                *lenp = 0;
+                return 0;
+        }
+        if (write)
+                return -EINVAL;
+        else {
+                len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
+                if (!access_ok(VERIFY_WRITE, buffer, len))
+                        return -EFAULT;
+
+                if (__copy_to_user(buffer, tmpbuf, len))
+                        return -EFAULT;
+        }
+        *lenp -= len;
+        *ppos += len;
+        return 0;
+}
+
 static int
 proc_dodebug(ctl_table *table, int write, struct file *file,
                                 void __user *buffer, size_t *lenp, loff_t *ppos)
@@ -147,6 +172,12 @@ static ctl_table debug_table[] = {
                 .mode           = 0644,
                 .proc_handler   = &proc_dodebug
         },
+        {
+                .procname       = "transports",
+                .maxlen         = 256,
+                .mode           = 0444,
+                .proc_handler   = &proc_do_xprt,
+        },
         { .ctl_name = 0 }
 };