Merge tag '9p-for-6.1' of https://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:
 "Smaller buffers for small messages and fixes.

  The highlight of this is Christian's patch to allocate smaller buffers
  for most metadata requests: 9p with a big msize would try to allocate
  large buffers when just 4 or 8k would be more than enough; this brings
  in nice performance improvements.

  There's also a few fixes for problems reported by syzkaller (thanks to
  Schspa Shi, Tetsuo Handa for tests and feedback/patches) as well as
  some minor cleanup"

* tag '9p-for-6.1' of https://github.com/martinetd/linux:
  net/9p: clarify trans_fd parse_opt failure handling
  net/9p: add __init/__exit annotations to module init/exit funcs
  net/9p: use a dedicated spinlock for trans_fd
  9p/trans_fd: always use O_NONBLOCK read/write
  net/9p: allocate appropriate reduced message buffers
  net/9p: add 'pooled_rbuffers' flag to struct p9_trans_module
  net/9p: add p9_msg_buf_size()
  9p: add P9_ERRMAX for 9p2000 and 9p2000.u
  net/9p: split message size argument into 't_size' and 'r_size' pair
  9p: trans_fd/p9_conn_cancel: drop client lock earlier

2 files changed, 8 insertions, 0 deletions

diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index 24a509f559ee..13abe013af21 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -331,6 +331,9 @@ enum p9_qid_t {
 /* size of header for zero copy read/write */
 #define P9_ZC_HDR_SZ 4096
 
+/* maximum length of an error string */
+#define P9_ERRMAX 128
+
 /**
  * struct p9_qid - file system entity information
  * @type: 8-bit type &p9_qid_t
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,