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>

1 files changed, 1 insertions, 45 deletions

diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index df58375ea6b3..b7d4e8aa5383 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -81,7 +81,7 @@ void p9stat_free(struct p9_wstat *stbuf)
 }
 EXPORT_SYMBOL(p9stat_free);
 
-static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
+size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
 {
         size_t len = min(pdu->size - pdu->offset, size);
         memcpy(data, &pdu->sdata[pdu->offset], len);
@@ -108,26 +108,6 @@ pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
         return size - len;
 }
 
-static size_t
-pdu_write_urw(struct p9_fcall *pdu, const char *kdata, const char __user *udata,
-                size_t size)
-{
-        BUG_ON(pdu->size > P9_IOHDRSZ);
-        pdu->pubuf = (char __user *)udata;
-        pdu->pkbuf = (char *)kdata;
-        pdu->pbuf_size = size;
-        return 0;
-}
-
-static size_t
-pdu_write_readdir(struct p9_fcall *pdu, const char *kdata, size_t size)
-{
-        BUG_ON(pdu->size > P9_READDIRHDRSZ);
-        pdu->pkbuf = (char *)kdata;
-        pdu->pbuf_size = size;
-        return 0;
-}
-
 /*
         b - int8_t
         w - int16_t
@@ -459,26 +439,6 @@ p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
                                         errcode = -EFAULT;
                         }
                         break;
-                case 'E':{
-                                 int32_t cnt = va_arg(ap, int32_t);
-                                 const char *k = va_arg(ap, const void *);
-                                 const char __user *u = va_arg(ap,
-                                                        const void __user *);
-                                 errcode = p9pdu_writef(pdu, proto_version, "d",
-                                                 cnt);
-                                 if (!errcode && pdu_write_urw(pdu, k, u, cnt))
-                                        errcode = -EFAULT;
-                         }
-                         break;
-                case 'F':{
-                                 int32_t cnt = va_arg(ap, int32_t);
-                                 const char *k = va_arg(ap, const void *);
-                                 errcode = p9pdu_writef(pdu, proto_version, "d",
-                                                 cnt);
-                                 if (!errcode && pdu_write_readdir(pdu, k, cnt))
-                                        errcode = -EFAULT;
-                         }
-                         break;
                 case 'U':{
                                 int32_t count = va_arg(ap, int32_t);
                                 const char __user *udata =
@@ -637,10 +597,6 @@ void p9pdu_reset(struct p9_fcall *pdu)
 {
         pdu->offset = 0;
         pdu->size = 0;
-        pdu->private = NULL;
-        pdu->pubuf = NULL;
-        pdu->pkbuf = NULL;
-        pdu->pbuf_size = 0;
 }
 
 int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,