net/9p: Handle get_user_pages_fast return properly

Use proper data type to handle get_user_pages_fast error condition. Also
do not treat EFAULT error as fatal.
Signed-off-by: NM. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

net/9p/client.c

@@ -614,7 +614,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 
 	err = c->trans_mod->request(c, req);
 	if (err < 0) {
-		if (err != -ERESTARTSYS)
+		if (err != -ERESTARTSYS && err != -EFAULT)
 			c->status = Disconnected;
 		goto reterr;
 	}

net/9p/trans_common.c

@@ -63,7 +63,7 @@ p9_payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len,
 		int nr_pages, u8 rw)
 {
 	uint32_t first_page_bytes = 0;
-	uint32_t pdata_mapped_pages;
+	int32_t pdata_mapped_pages;
 	struct trans_rpage_info  *rpinfo;
 
 	*pdata_off = (__force size_t)req->tc->pubuf & (PAGE_SIZE-1);
@@ -75,14 +75,9 @@ p9_payload_gup(struct p9_req_t *req, size_t *pdata_off, int *pdata_len,
 	rpinfo = req->tc->private;
 	pdata_mapped_pages = get_user_pages_fast((unsigned long)req->tc->pubuf,
 			nr_pages, rw, &rpinfo->rp_data[0]);
+	if (pdata_mapped_pages <= 0)
+		return pdata_mapped_pages;
 
-	if (pdata_mapped_pages < 0) {
-		printk(KERN_ERR "get_user_pages_fast failed:%d udata:%p"
-				"nr_pages:%d\n", pdata_mapped_pages,
-				req->tc->pubuf, nr_pages);
-		pdata_mapped_pages = 0;
-		return -EIO;
-	}
 	rpinfo->rp_nr_pages = pdata_mapped_pages;
 	if (*pdata_off) {
 		*pdata_len = first_page_bytes;