From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit
---
net/9p/trans_common.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 net/9p/trans_common.c
(limited to 'net/9p/trans_common.c')
diff --git a/net/9p/trans_common.c b/net/9p/trans_common.c
new file mode 100644
index 00000000..9a70ebde
--- /dev/null
+++ b/net/9p/trans_common.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <linux/scatterlist.h>
+#include "trans_common.h"
+
+/**
+ * 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)
+{
+ int i = 0;
+
+ while (rpinfo->rp_data[i] && rpinfo->rp_nr_pages--) {
+ put_page(rpinfo->rp_data[i]);
+ i++;
+ }
+}
+EXPORT_SYMBOL(p9_release_req_pages);
+
+/**
+ * p9_nr_pages - Return number of pages needed to accommodate the payload.
+ */
+int
+p9_nr_pages(struct p9_req_t *req)
+{
+ 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;
+ return end_page - start_page;
+}
+EXPORT_SYMBOL(p9_nr_pages);
+
+/**
+ * payload_gup - Translates user buffer into kernel pages and
+ * pins them either for read/write through get_user_pages_fast().
+ * @req: Request to be sent to server.
+ * @pdata_off: data offset into the first page after translation (gup).
+ * @pdata_len: Total length of the IO. gup may not return requested # of 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);
+
+ 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;
+
+ 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);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(p9_payload_gup);
--
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