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, 15 insertions, 38 deletions

diff --git a/net/9p/trans_common.c b/net/9p/trans_common.c
index 9a70ebdec56..de8df957867 100644
--- a/net/9p/trans_common.c
+++ b/net/9p/trans_common.c
@@ -21,30 +21,25 @@
 
 /**
  *  p9_release_req_pages - Release pages after the transaction.
- *  @*private: PDU's private page of struct trans_rpage_info
  */
-void
-p9_release_req_pages(struct trans_rpage_info *rpinfo)
+void p9_release_pages(struct page **pages, int nr_pages)
 {
 	int i = 0;
-
-	while (rpinfo->rp_data[i] && rpinfo->rp_nr_pages--) {
-		put_page(rpinfo->rp_data[i]);
+	while (pages[i] && nr_pages--) {
+		put_page(pages[i]);
 		i++;
 	}
 }
-EXPORT_SYMBOL(p9_release_req_pages);
+EXPORT_SYMBOL(p9_release_pages);
 
 /**
  * p9_nr_pages - Return number of pages needed to accommodate the payload.
  */
-int
-p9_nr_pages(struct p9_req_t *req)
+int p9_nr_pages(char *data, int len)
 {
 	unsigned long start_page, end_page;
-	start_page =  (unsigned long)req->tc->pubuf >> PAGE_SHIFT;
-	end_page = ((unsigned long)req->tc->pubuf + req->tc->pbuf_size +
-			PAGE_SIZE - 1) >> PAGE_SHIFT;
+	start_page =  (unsigned long)data >> PAGE_SHIFT;
+	end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	return end_page - start_page;
 }
 EXPORT_SYMBOL(p9_nr_pages);
@@ -58,35 +53,17 @@ EXPORT_SYMBOL(p9_nr_pages);
  * @nr_pages: number of pages to accommodate the payload
  * @rw: Indicates if the pages are for read or write.
  */
-int
-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;
-	int32_t pdata_mapped_pages;
-	struct trans_rpage_info  *rpinfo;
-
-	*pdata_off = (__force size_t)req->tc->pubuf & (PAGE_SIZE-1);
 
-	if (*pdata_off)
-		first_page_bytes = min(((size_t)PAGE_SIZE - *pdata_off),
-				       req->tc->pbuf_size);
+int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write)
+{
+	int nr_mapped_pages;
 
-	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;
+	nr_mapped_pages = get_user_pages_fast((unsigned long)data,
+					      *nr_pages, write, pages);
+	if (nr_mapped_pages <= 0)
+		return nr_mapped_pages;
 
-	rpinfo->rp_nr_pages = pdata_mapped_pages;
-	if (*pdata_off) {
-		*pdata_len = first_page_bytes;
-		*pdata_len += min((req->tc->pbuf_size - *pdata_len),
-				((size_t)pdata_mapped_pages - 1) << PAGE_SHIFT);
-	} else {
-		*pdata_len = min(req->tc->pbuf_size,
-				(size_t)pdata_mapped_pages << PAGE_SHIFT);
-	}
+	*nr_pages = nr_mapped_pages;
 	return 0;
 }
 EXPORT_SYMBOL(p9_payload_gup);