[PATCH v6 10/11] net/9p: add 'pooled_rbuffers' flag to struct p9_trans_module

[Christian Schoenebeck <linux_oss@crudebyte.com>]

This is a preparatory change for the subsequent patch: the RDMA
transport pulls the buffers for its 9p response messages from a
shared pool. [1] So this case has to be considered when choosing
an appropriate response message size in the subsequent patch.

Link: https://lore.kernel.org/all/Ys3jjg52EIyITPua@codewreck.org/ [1]
Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
---
 include/net/9p/transport.h | 5 +++++
 net/9p/trans_fd.c          | 1 +
 net/9p/trans_rdma.c        | 1 +
 net/9p/trans_virtio.c      | 1 +
 net/9p/trans_xen.c         | 1 +
 5 files changed, 9 insertions(+)

diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index ff842f963071..766ec07c9599 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -19,6 +19,10 @@
  * @list: used to maintain a list of currently available transports
  * @name: the human-readable name of the transport
  * @maxsize: transport provided maximum packet size
+ * @pooled_rbuffers: currently only set for RDMA transport which pulls the
+ *                   response buffers from a shared pool, and accordingly
+ *                   we're less flexible when choosing the response message
+ *                   size in this case
  * @def: set if this transport should be considered the default
  * @create: member function to create a new connection on this transport
  * @close: member function to discard a connection on this transport
@@ -38,6 +42,7 @@ struct p9_trans_module {
 	struct list_head list;
 	char *name;		/* name of transport */
 	int maxsize;		/* max message size of transport */
+	bool pooled_rbuffers;
 	int def;		/* this transport should be default */
 	struct module *owner;
 	int (*create)(struct p9_client *client,
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 8f8f95e39b03..eecbb5332bea 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -1081,6 +1081,7 @@ p9_fd_create(struct p9_client *client, const char *addr, char *args)
 static struct p9_trans_module p9_tcp_trans = {
 	.name = "tcp",
 	.maxsize = MAX_SOCK_BUF,
+	.pooled_rbuffers = false,
 	.def = 0,
 	.create = p9_fd_create_tcp,
 	.close = p9_fd_close,
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 88e563826674..24f287baee70 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -739,6 +739,7 @@ rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 static struct p9_trans_module p9_rdma_trans = {
 	.name = "rdma",
 	.maxsize = P9_RDMA_MAXSIZE,
+	.pooled_rbuffers = true,
 	.def = 0,
 	.owner = THIS_MODULE,
 	.create = rdma_create_trans,
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 52d00cb3c105..d47b28b3f02a 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -1011,6 +1011,7 @@ static struct p9_trans_module p9_virtio_trans = {
 	 */
 	.maxsize = PAGE_SIZE *
 		((VIRTQUEUE_SG_NSGL_DEFAULT * SG_USER_PAGES_PER_LIST) - 3),
+	.pooled_rbuffers = false,
 	.def = 1,
 	.owner = THIS_MODULE,
 };
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 833cd3792c51..3434a080abfa 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -246,6 +246,7 @@ static irqreturn_t xen_9pfs_front_event_handler(int irq, void *r)
 static struct p9_trans_module p9_xen_trans = {
 	.name = "xen",
 	.maxsize = 1 << (XEN_9PFS_RING_ORDER + XEN_PAGE_SHIFT - 2),
+	.pooled_rbuffers = false,
 	.def = 1,
 	.create = p9_xen_create,
 	.close = p9_xen_close,
-- 
2.30.2