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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/dma/iovlock.c
2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
3 * Portions based on net/core/datagram.c and copyrighted by their authors.
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation; either version 2 of the License, or (at your option)
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 59
17 * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * The full GNU General Public License is included in this distribution in the
20 * file called COPYING.
24 * This code allows the net stack to make use of a DMA engine for
25 * skb to iovec copies.
28 #include <linux/dmaengine.h>
29 #include <linux/pagemap.h>
30 #include <net/tcp.h> /* for memcpy_toiovec */
32 #include <asm/uaccess.h>
34 static int num_pages_spanned(struct iovec
*iov
)
37 ((PAGE_ALIGN((unsigned long)iov
->iov_base
+ iov
->iov_len
) -
38 ((unsigned long)iov
->iov_base
& PAGE_MASK
)) >> PAGE_SHIFT
);
42 * Pin down all the iovec pages needed for len bytes.
43 * Return a struct dma_pinned_list to keep track of pages pinned down.
45 * We are allocating a single chunk of memory, and then carving it up into
46 * 3 sections, the latter 2 whose size depends on the number of iovecs and the
47 * total number of pages, respectively.
49 struct dma_pinned_list
*dma_pin_iovec_pages(struct iovec
*iov
, size_t len
)
51 struct dma_pinned_list
*local_list
;
56 int iovec_len_used
= 0;
57 int iovec_pages_used
= 0;
60 /* don't pin down non-user-based iovecs */
61 if (segment_eq(get_fs(), KERNEL_DS
))
64 /* determine how many iovecs/pages there are, up front */
66 iovec_len_used
+= iov
[nr_iovecs
].iov_len
;
67 iovec_pages_used
+= num_pages_spanned(&iov
[nr_iovecs
]);
69 } while (iovec_len_used
< len
);
71 /* single kmalloc for pinned list, page_list[], and the page arrays */
72 local_list
= kmalloc(sizeof(*local_list
)
73 + (nr_iovecs
* sizeof (struct dma_page_list
))
74 + (iovec_pages_used
* sizeof (struct page
*)), GFP_KERNEL
);
80 /* list of pages starts right after the page list array */
81 pages
= (struct page
**) &local_list
->page_list
[nr_iovecs
];
83 for (i
= 0; i
< nr_iovecs
; i
++) {
84 struct dma_page_list
*page_list
= &local_list
->page_list
[i
];
86 len
-= iov
[i
].iov_len
;
88 if (!access_ok(VERIFY_WRITE
, iov
[i
].iov_base
, iov
[i
].iov_len
)) {
93 page_list
->nr_pages
= num_pages_spanned(&iov
[i
]);
94 page_list
->base_address
= iov
[i
].iov_base
;
96 page_list
->pages
= pages
;
97 pages
+= page_list
->nr_pages
;
100 down_read(¤t
->mm
->mmap_sem
);
101 ret
= get_user_pages(
104 (unsigned long) iov
[i
].iov_base
,
110 up_read(¤t
->mm
->mmap_sem
);
112 if (ret
!= page_list
->nr_pages
) {
117 local_list
->nr_iovecs
= i
+ 1;
123 dma_unpin_iovec_pages(local_list
);
128 void dma_unpin_iovec_pages(struct dma_pinned_list
*pinned_list
)
135 for (i
= 0; i
< pinned_list
->nr_iovecs
; i
++) {
136 struct dma_page_list
*page_list
= &pinned_list
->page_list
[i
];
137 for (j
= 0; j
< page_list
->nr_pages
; j
++) {
138 set_page_dirty_lock(page_list
->pages
[j
]);
139 page_cache_release(page_list
->pages
[j
]);
148 * We have already pinned down the pages we will be using in the iovecs.
149 * Each entry in iov array has corresponding entry in pinned_list->page_list.
150 * Using array indexing to keep iov[] and page_list[] in sync.
151 * Initial elements in iov array's iov->iov_len will be 0 if already copied into
153 * iov array length remaining guaranteed to be bigger than len.
155 dma_cookie_t
dma_memcpy_to_iovec(struct dma_chan
*chan
, struct iovec
*iov
,
156 struct dma_pinned_list
*pinned_list
, unsigned char *kdata
, size_t len
)
160 dma_cookie_t dma_cookie
= 0;
165 return memcpy_toiovec(iov
, kdata
, len
);
168 while (iovec_idx
< pinned_list
->nr_iovecs
) {
169 struct dma_page_list
*page_list
;
171 /* skip already used-up iovecs */
172 while (!iov
[iovec_idx
].iov_len
)
175 page_list
= &pinned_list
->page_list
[iovec_idx
];
177 iov_byte_offset
= ((unsigned long)iov
[iovec_idx
].iov_base
& ~PAGE_MASK
);
178 page_idx
= (((unsigned long)iov
[iovec_idx
].iov_base
& PAGE_MASK
)
179 - ((unsigned long)page_list
->base_address
& PAGE_MASK
)) >> PAGE_SHIFT
;
181 /* break up copies to not cross page boundary */
182 while (iov
[iovec_idx
].iov_len
) {
183 copy
= min_t(int, PAGE_SIZE
- iov_byte_offset
, len
);
184 copy
= min_t(int, copy
, iov
[iovec_idx
].iov_len
);
186 dma_cookie
= dma_async_memcpy_buf_to_pg(chan
,
187 page_list
->pages
[page_idx
],
193 iov
[iovec_idx
].iov_len
-= copy
;
194 iov
[iovec_idx
].iov_base
+= copy
;
206 /* really bad if we ever run out of iovecs */
211 dma_cookie_t
dma_memcpy_pg_to_iovec(struct dma_chan
*chan
, struct iovec
*iov
,
212 struct dma_pinned_list
*pinned_list
, struct page
*page
,
213 unsigned int offset
, size_t len
)
217 dma_cookie_t dma_cookie
= 0;
222 /* this needs as-yet-unimplemented buf-to-buff, so punt. */
223 /* TODO: use dma for this */
224 if (!chan
|| !pinned_list
) {
225 u8
*vaddr
= kmap(page
);
226 err
= memcpy_toiovec(iov
, vaddr
+ offset
, len
);
232 while (iovec_idx
< pinned_list
->nr_iovecs
) {
233 struct dma_page_list
*page_list
;
235 /* skip already used-up iovecs */
236 while (!iov
[iovec_idx
].iov_len
)
239 page_list
= &pinned_list
->page_list
[iovec_idx
];
241 iov_byte_offset
= ((unsigned long)iov
[iovec_idx
].iov_base
& ~PAGE_MASK
);
242 page_idx
= (((unsigned long)iov
[iovec_idx
].iov_base
& PAGE_MASK
)
243 - ((unsigned long)page_list
->base_address
& PAGE_MASK
)) >> PAGE_SHIFT
;
245 /* break up copies to not cross page boundary */
246 while (iov
[iovec_idx
].iov_len
) {
247 copy
= min_t(int, PAGE_SIZE
- iov_byte_offset
, len
);
248 copy
= min_t(int, copy
, iov
[iovec_idx
].iov_len
);
250 dma_cookie
= dma_async_memcpy_pg_to_pg(chan
,
251 page_list
->pages
[page_idx
],
258 iov
[iovec_idx
].iov_len
-= copy
;
259 iov
[iovec_idx
].iov_base
+= copy
;
271 /* really bad if we ever run out of iovecs */