net/9p: add 'pooled_rbuffers' flag to struct p9_trans_module

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/
Link: https://lkml.kernel.org/r/79d24310226bc4eb037892b5c097ec4ad4819a03.1657920926.git.linux_oss@crudebyte.com
Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index ff842f9..766ec07 100644 (file)
--- 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 60fcc6b..25d422c 100644 (file)
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -1083,6 +1083,7 @@ 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 d817d37..6ff7067 100644 (file)
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -739,6 +739,7 @@ error:
 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 b84d35c..e757f06 100644 (file)
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -802,6 +802,7 @@ static struct p9_trans_module p9_virtio_trans = {
         * page in zero copy.
         */
        .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
+       .pooled_rbuffers = false,
        .def = 1,
        .owner = THIS_MODULE,
 };

diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 227f89c..41c57d4 100644 (file)
--- 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,