70 lines
2.0 KiB
C
70 lines
2.0 KiB
C
/*
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* Copyright IBM Corporation, 2010
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* Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2.1 of the GNU Lesser General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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*/
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include <linux/scatterlist.h>
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#include "trans_common.h"
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/**
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* p9_release_req_pages - Release pages after the transaction.
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*/
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void p9_release_pages(struct page **pages, int nr_pages)
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{
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int i = 0;
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while (pages[i] && nr_pages--) {
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put_page(pages[i]);
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i++;
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}
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}
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EXPORT_SYMBOL(p9_release_pages);
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/**
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* p9_nr_pages - Return number of pages needed to accommodate the payload.
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*/
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int p9_nr_pages(char *data, int len)
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{
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unsigned long start_page, end_page;
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start_page = (unsigned long)data >> PAGE_SHIFT;
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end_page = ((unsigned long)data + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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return end_page - start_page;
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}
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EXPORT_SYMBOL(p9_nr_pages);
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/**
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* payload_gup - Translates user buffer into kernel pages and
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* pins them either for read/write through get_user_pages_fast().
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* @req: Request to be sent to server.
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* @pdata_off: data offset into the first page after translation (gup).
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* @pdata_len: Total length of the IO. gup may not return requested # of pages.
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* @nr_pages: number of pages to accommodate the payload
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* @rw: Indicates if the pages are for read or write.
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*/
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int p9_payload_gup(char *data, int *nr_pages, struct page **pages, int write)
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{
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int nr_mapped_pages;
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nr_mapped_pages = get_user_pages_fast((unsigned long)data,
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*nr_pages, write, pages);
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if (nr_mapped_pages <= 0)
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return nr_mapped_pages;
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*nr_pages = nr_mapped_pages;
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return 0;
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}
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EXPORT_SYMBOL(p9_payload_gup);
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