[PATCH 3/3] sunrpc: Add a sysfs file for adding a new xprt

Anna Schumaker
2025-01-08T21:36:35Z

From: Anna Schumaker <anna.schumaker@oracle.com>

Writing to this file will clone the 'main' xprt of an xprt_switch and
add it to be used as an additional connection.

Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
---
include/linux/sunrpc/xprtmultipath.h | 1 +
net/sunrpc/sysfs.c | 54 ++++++++++++++++++++++++++++
net/sunrpc/xprtmultipath.c | 21 +++++++++++
3 files changed, 76 insertions(+)

diff --git a/include/linux/sunrpc/xprtmultipath.h b/include/linux/sunrpc/xprtmultipath.h
index c0514c684b2c..c827c6ef0bc5 100644
--- a/include/linux/sunrpc/xprtmultipath.h
+++ b/include/linux/sunrpc/xprtmultipath.h
@@ -56,6 +56,7 @@ extern void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt);
extern void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt, bool offline);
+extern struct rpc_xprt *rpc_xprt_switch_get_main_xprt(struct rpc_xprt_switch *xps);

extern void xprt_iter_init(struct rpc_xprt_iter *xpi,
struct rpc_xprt_switch *xps);
diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
index dc3b7cd70000..ce7dae140770 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -250,6 +250,55 @@ static ssize_t rpc_sysfs_xprt_switch_info_show(struct kobject *kobj,
return ret;
}

+static ssize_t rpc_sysfs_xprt_switch_add_xprt_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "# add one xprt to this xprt_switch\n");
+}
+
+static ssize_t rpc_sysfs_xprt_switch_add_xprt_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rpc_xprt_switch *xprt_switch =
+ rpc_sysfs_xprt_switch_kobj_get_xprt(kobj);
+ struct xprt_create xprt_create_args;
+ struct rpc_xprt *xprt, *new;
+
+ if (!xprt_switch)
+ return 0;
+
+ xprt = rpc_xprt_switch_get_main_xprt(xprt_switch);
+ if (!xprt)
+ goto out;
+
+ xprt_create_args.ident = xprt->xprt_class->ident;
+ xprt_create_args.net = xprt->xprt_net;
+ xprt_create_args.dstaddr = (struct sockaddr *)&xprt->addr;
+ xprt_create_args.addrlen = xprt->addrlen;
+ xprt_create_args.servername = xprt->servername;
+ xprt_create_args.bc_xprt = xprt->bc_xprt;
+ xprt_create_args.xprtsec = xprt->xprtsec;
+ xprt_create_args.connect_timeout = xprt->connect_timeout;
+ xprt_create_args.reconnect_timeout = xprt->max_reconnect_timeout;
+
+ new = xprt_create_transport(&xprt_create_args);
+ if (IS_ERR_OR_NULL(new)) {
+ count = PTR_ERR(new);
+ goto out_put_xprt;
+ }
+
+ rpc_xprt_switch_add_xprt(xprt_switch, new);
+ xprt_put(new);
+
+out_put_xprt:
+ xprt_put(xprt);
+out:
+ xprt_switch_put(xprt_switch);
+ return count;
+}
+
static ssize_t rpc_sysfs_xprt_dstaddr_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
@@ -451,8 +500,13 @@ ATTRIBUTE_GROUPS(rpc_sysfs_xprt);
static struct kobj_attribute rpc_sysfs_xprt_switch_info =
__ATTR(xprt_switch_info, 0444, rpc_sysfs_xprt_switch_info_show, NULL);

+static struct kobj_attribute rpc_sysfs_xprt_switch_add_xprt =
+ __ATTR(xprt_switch_add_xprt, 0644, rpc_sysfs_xprt_switch_add_xprt_show,
+ rpc_sysfs_xprt_switch_add_xprt_store);
+
static struct attribute *rpc_sysfs_xprt_switch_attrs[] = {
&rpc_sysfs_xprt_switch_info.attr,
+ &rpc_sysfs_xprt_switch_add_xprt.attr,
NULL,
};
ATTRIBUTE_GROUPS(rpc_sysfs_xprt_switch);
diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c
index 720d3ba742ec..a07b81ce93c3 100644
--- a/net/sunrpc/xprtmultipath.c
+++ b/net/sunrpc/xprtmultipath.c
@@ -92,6 +92,27 @@ void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
xprt_put(xprt);
}

+/**
+ * rpc_xprt_switch_get_main_xprt - Get the 'main' xprt for an xprt switch.
+ * @xps: pointer to struct rpc_xprt_switch.
+ */
+struct rpc_xprt *rpc_xprt_switch_get_main_xprt(struct rpc_xprt_switch *xps)
+{
+ struct rpc_xprt_iter xpi;
+ struct rpc_xprt *xprt;
+
+ xprt_iter_init_listall(&xpi, xps);
+
+ xprt = xprt_iter_get_xprt(&xpi);
+ while (xprt && !xprt->main) {
+ xprt_put(xprt);
+ xprt = xprt_iter_get_next(&xpi);
+ }
+
+ xprt_iter_destroy(&xpi);
+ return xprt;
+}
+
static DEFINE_IDA(rpc_xprtswitch_ids);

void xprt_multipath_cleanup_ids(void)
--
2.47.1