fs/9p: Update zero-copy implementation in 9p

* remove lot of update to different data structure
* add a seperate callback for zero copy request.
* above makes non zero copy code path simpler
* remove conditionalizing TREAD/TREADDIR/TWRITE in the zero copy path
* Fix the dotu p9_check_errors with zero copy. Add sufficient doc around
* Add support for both in and output buffers in zero copy callback
* pin and unpin pages in the same context
* use helpers instead of defining page offset and rest of page ourself
* Fix mem leak in p9_check_errors
* Remove 'E' and 'F' in p9pdu_vwritef

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

2 files changed, 5 insertions, 16 deletions

diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index a6326ef8ade..d83a0130087 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -359,6 +359,9 @@ enum p9_qid_t {
 /* Room for readdir header */
 #define P9_READDIRHDRSZ 24
 
+/* size of header for zero copy read/write */
+#define P9_ZC_HDR_SZ 4096
+
 /**
  * struct p9_qid - file system entity information
  * @type: 8-bit type &p9_qid_t
@@ -555,10 +558,6 @@ struct p9_rstatfs {
  * @tag: transaction id of the request
  * @offset: used by marshalling routines to track current position in buffer
  * @capacity: used by marshalling routines to track total malloc'd capacity
- * @pubuf: Payload user buffer given by the caller
- * @pkbuf: Payload kernel buffer given by the caller
- * @pbuf_size: pubuf/pkbuf(only one will be !NULL) size to be read/write.
- * @private: For transport layer's use.
  * @sdata: payload
  *
  * &p9_fcall represents the structure for all 9P RPC
@@ -575,10 +574,6 @@ struct p9_fcall {
 
         size_t offset;
         size_t capacity;
-        char __user *pubuf;
-        char *pkbuf;
-        size_t pbuf_size;
-        void *private;
 
         u8 *sdata;
 };
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index 83531ebeee9..adcbb20f651 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -26,13 +26,6 @@
 #ifndef NET_9P_TRANSPORT_H
 #define NET_9P_TRANSPORT_H
 
-#define P9_TRANS_PREF_PAYLOAD_MASK 0x1
-
-/* Default. Add Payload to PDU before sending it down to transport layer */
-#define P9_TRANS_PREF_PAYLOAD_DEF  0x0
-/* Send pay load separately to transport layer along with PDU.*/
-#define P9_TRANS_PREF_PAYLOAD_SEP  0x1
-
 /**
  * struct p9_trans_module - transport module interface
  * @list: used to maintain a list of currently available transports
@@ -56,13 +49,14 @@ struct p9_trans_module {
         struct list_head list;
         char *name;             /* name of transport */
         int maxsize;            /* max message size of transport */
-        int pref;               /* Preferences of this transport */
         int def;                /* this transport should be default */
         struct module *owner;
         int (*create)(struct p9_client *, const char *, char *);
         void (*close) (struct p9_client *);
         int (*request) (struct p9_client *, struct p9_req_t *req);
         int (*cancel) (struct p9_client *, struct p9_req_t *req);
+        int (*zc_request)(struct p9_client *, struct p9_req_t *,
+                          char *, char *, int , int, int, int);
 };
 
 void v9fs_register_trans(struct p9_trans_module *m);