9p: Implement show_options

Implement the show_options superblock op for 9p as part of a bid to get
rid of s_options and generic_show_options() to make it easier to implement
a context-based mount where the mount options can be passed individually
over a file descriptor.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Ron Minnich <rminnich@sandia.gov>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 81 insertions, 6 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 1218fb3b52da..4674235b0d9b 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -37,6 +37,7 @@
 #include <linux/uio.h>
 #include <net/9p/9p.h>
 #include <linux/parser.h>
+#include <linux/seq_file.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
 #include "protocol.h"
@@ -77,6 +78,30 @@ inline int p9_is_proto_dotu(struct p9_client *clnt)
 }
 EXPORT_SYMBOL(p9_is_proto_dotu);
 
+int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
+{
+        if (clnt->msize != 8192)
+                seq_printf(m, ",msize=%u", clnt->msize);
+        seq_printf(m, "trans=%s", clnt->trans_mod->name);
+
+        switch (clnt->proto_version) {
+        case p9_proto_legacy:
+                seq_puts(m, ",noextend");
+                break;
+        case p9_proto_2000u:
+                seq_puts(m, ",version=9p2000.u");
+                break;
+        case p9_proto_2000L:
+                /* Default */
+                break;
+        }
+
+        if (clnt->trans_mod->show_options)
+                return clnt->trans_mod->show_options(m, clnt);
+        return 0;
+}
+EXPORT_SYMBOL(p9_show_client_options);
+
 /*
  * Some error codes are taken directly from the server replies,
  * make sure they are valid.
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 7bc2208b6cc4..f2e0eaf58018 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -41,6 +41,7 @@
 #include <linux/file.h>
 #include <linux/parser.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
@@ -51,6 +52,9 @@
 #define MAX_SOCK_BUF (64*1024)
 #define MAXPOLLWADDR    2
 
+static struct p9_trans_module p9_tcp_trans;
+static struct p9_trans_module p9_fd_trans;
+
 /**
  * struct p9_fd_opts - per-transport options
  * @rfd: file descriptor for reading (trans=fd)
@@ -63,7 +67,7 @@ struct p9_fd_opts {
         int rfd;
         int wfd;
         u16 port;
-        int privport;
+        bool privport;
 };
 
 /*
@@ -720,6 +724,20 @@ static int p9_fd_cancelled(struct p9_client *client, struct p9_req_t *req)
         return 0;
 }
 
+static int p9_fd_show_options(struct seq_file *m, struct p9_client *clnt)
+{
+        if (clnt->trans_mod == &p9_tcp_trans) {
+                if (clnt->trans_opts.tcp.port != P9_PORT)
+                        seq_printf(m, "port=%u", clnt->trans_opts.tcp.port);
+        } else if (clnt->trans_mod == &p9_fd_trans) {
+                if (clnt->trans_opts.fd.rfd != ~0)
+                        seq_printf(m, "rfd=%u", clnt->trans_opts.fd.rfd);
+                if (clnt->trans_opts.fd.wfd != ~0)
+                        seq_printf(m, "wfd=%u", clnt->trans_opts.fd.wfd);
+        }
+        return 0;
+}
+
 /**
  * parse_opts - parse mount options into p9_fd_opts structure
  * @params: options string passed from mount
@@ -738,7 +756,7 @@ static int parse_opts(char *params, struct p9_fd_opts *opts)
         opts->port = P9_PORT;
         opts->rfd = ~0;
         opts->wfd = ~0;
-        opts->privport = 0;
+        opts->privport = false;
 
         if (!params)
                 return 0;
@@ -776,7 +794,7 @@ static int parse_opts(char *params, struct p9_fd_opts *opts)
                         opts->wfd = option;
                         break;
                 case Opt_privport:
-                        opts->privport = 1;
+                        opts->privport = true;
                         break;
                 default:
                         continue;
@@ -942,6 +960,8 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 
         csocket = NULL;
 
+        client->trans_opts.tcp.port = opts.port;
+        client->trans_opts.tcp.privport = opts.privport;
         sin_server.sin_family = AF_INET;
         sin_server.sin_addr.s_addr = in_aton(addr);
         sin_server.sin_port = htons(opts.port);
@@ -1020,6 +1040,8 @@ p9_fd_create(struct p9_client *client, const char *addr, char *args)
         struct p9_fd_opts opts;
 
         parse_opts(args, &opts);
+        client->trans_opts.fd.rfd = opts.rfd;
+        client->trans_opts.fd.wfd = opts.wfd;
 
         if (opts.rfd == ~0 || opts.wfd == ~0) {
                 pr_err("Insufficient options for proto=fd\n");
@@ -1044,6 +1066,7 @@ static struct p9_trans_module p9_tcp_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
@@ -1056,6 +1079,7 @@ static struct p9_trans_module p9_unix_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
@@ -1068,6 +1092,7 @@ static struct p9_trans_module p9_fd_trans = {
         .request = p9_fd_request,
         .cancel = p9_fd_cancel,
         .cancelled = p9_fd_cancelled,
+        .show_options = p9_fd_show_options,
         .owner = THIS_MODULE,
 };
 
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 553ed4ecb6a0..6d8e3031978f 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -43,6 +43,7 @@
 #include <linux/parser.h>
 #include <linux/semaphore.h>
 #include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 #include <net/9p/transport.h>
@@ -70,6 +71,8 @@
  * @dm_mr: DMA Memory Region pointer
  * @lkey: The local access only memory region key
  * @timeout: Number of uSecs to wait for connection management events
+ * @privport: Whether a privileged port may be used
+ * @port: The port to use
  * @sq_depth: The depth of the Send Queue
  * @sq_sem: Semaphore for the SQ
  * @rq_depth: The depth of the Receive Queue.
@@ -95,6 +98,8 @@ struct p9_trans_rdma {
         struct ib_qp *qp;
         struct ib_cq *cq;
         long timeout;
+        bool privport;
+        u16 port;
         int sq_depth;
         struct semaphore sq_sem;
         int rq_depth;
@@ -133,10 +138,10 @@ struct p9_rdma_context {
  */
 struct p9_rdma_opts {
         short port;
+        bool privport;
         int sq_depth;
         int rq_depth;
         long timeout;
-        int privport;
 };
 
 /*
@@ -159,6 +164,23 @@ static match_table_t tokens = {
         {Opt_err, NULL},
 };
 
+static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
+{
+        struct p9_trans_rdma *rdma = clnt->trans;
+
+        if (rdma->port != P9_PORT)
+                seq_printf(m, ",port=%u", rdma->port);
+        if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
+                seq_printf(m, ",sq=%u", rdma->sq_depth);
+        if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
+                seq_printf(m, ",rq=%u", rdma->rq_depth);
+        if (rdma->timeout != P9_RDMA_TIMEOUT)
+                seq_printf(m, ",timeout=%lu", rdma->timeout);
+        if (rdma->privport)
+                seq_puts(m, ",privport");
+        return 0;
+}
+
 /**
  * parse_opts - parse mount options into rdma options structure
  * @params: options string passed from mount
@@ -177,7 +199,7 @@ static int parse_opts(char *params, struct p9_rdma_opts *opts)
         opts->sq_depth = P9_RDMA_SQ_DEPTH;
         opts->rq_depth = P9_RDMA_RQ_DEPTH;
         opts->timeout = P9_RDMA_TIMEOUT;
-        opts->privport = 0;
+        opts->privport = false;
 
         if (!params)
                 return 0;
@@ -218,7 +240,7 @@ static int parse_opts(char *params, struct p9_rdma_opts *opts)
                         opts->timeout = option;
                         break;
                 case Opt_privport:
-                        opts->privport = 1;
+                        opts->privport = true;
                         break;
                 default:
                         continue;
@@ -560,6 +582,8 @@ static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
         if (!rdma)
                 return NULL;
 
+        rdma->port = opts->port;
+        rdma->privport = opts->privport;
         rdma->sq_depth = opts->sq_depth;
         rdma->rq_depth = opts->rq_depth;
         rdma->timeout = opts->timeout;
@@ -733,6 +757,7 @@ static struct p9_trans_module p9_rdma_trans = {
         .request = rdma_request,
         .cancel = rdma_cancel,
         .cancelled = rdma_cancelled,
+        .show_options = p9_rdma_show_options,
 };
 
 /**