[I/OAT]: Utility functions for offloading sk_buff to iovec copies
Provides for pinning user space pages in memory, copying to iovecs, and copying from sk_buffs including fragmented and chained sk_buffs. Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chris Leech
David S. Miller
parent
db21733488
commit
de5506e155
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@ -1,2 +1,3 @@
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obj-y += dmaengine.o
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obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
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obj-$(CONFIG_NET_DMA) += iovlock.o
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obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
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@ -0,0 +1,301 @@
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/*
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* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
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* Portions based on net/core/datagram.c and copyrighted by their authors.
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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 the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The full GNU General Public License is included in this distribution in the
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* file called COPYING.
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*/
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/*
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* This code allows the net stack to make use of a DMA engine for
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* skb to iovec copies.
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*/
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#include <linux/dmaengine.h>
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#include <linux/pagemap.h>
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#include <net/tcp.h> /* for memcpy_toiovec */
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#include <asm/io.h>
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#include <asm/uaccess.h>
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int num_pages_spanned(struct iovec *iov)
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{
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return
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((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
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((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT);
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}
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/*
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* Pin down all the iovec pages needed for len bytes.
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* Return a struct dma_pinned_list to keep track of pages pinned down.
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*
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* We are allocating a single chunk of memory, and then carving it up into
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* 3 sections, the latter 2 whose size depends on the number of iovecs and the
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* total number of pages, respectively.
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*/
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struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len)
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{
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struct dma_pinned_list *local_list;
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struct page **pages;
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int i;
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int ret;
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int nr_iovecs = 0;
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int iovec_len_used = 0;
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int iovec_pages_used = 0;
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long err;
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/* don't pin down non-user-based iovecs */
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if (segment_eq(get_fs(), KERNEL_DS))
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return NULL;
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/* determine how many iovecs/pages there are, up front */
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do {
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iovec_len_used += iov[nr_iovecs].iov_len;
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iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]);
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nr_iovecs++;
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} while (iovec_len_used < len);
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/* single kmalloc for pinned list, page_list[], and the page arrays */
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local_list = kmalloc(sizeof(*local_list)
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+ (nr_iovecs * sizeof (struct dma_page_list))
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+ (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL);
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if (!local_list) {
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err = -ENOMEM;
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goto out;
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}
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/* list of pages starts right after the page list array */
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pages = (struct page **) &local_list->page_list[nr_iovecs];
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for (i = 0; i < nr_iovecs; i++) {
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struct dma_page_list *page_list = &local_list->page_list[i];
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len -= iov[i].iov_len;
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if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len)) {
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err = -EFAULT;
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goto unpin;
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}
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page_list->nr_pages = num_pages_spanned(&iov[i]);
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page_list->base_address = iov[i].iov_base;
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page_list->pages = pages;
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pages += page_list->nr_pages;
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/* pin pages down */
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down_read(¤t->mm->mmap_sem);
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ret = get_user_pages(
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current,
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current->mm,
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(unsigned long) iov[i].iov_base,
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page_list->nr_pages,
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1, /* write */
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0, /* force */
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page_list->pages,
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NULL);
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up_read(¤t->mm->mmap_sem);
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if (ret != page_list->nr_pages) {
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err = -ENOMEM;
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goto unpin;
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}
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local_list->nr_iovecs = i + 1;
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}
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return local_list;
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unpin:
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dma_unpin_iovec_pages(local_list);
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out:
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return ERR_PTR(err);
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}
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void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
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{
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int i, j;
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if (!pinned_list)
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return;
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for (i = 0; i < pinned_list->nr_iovecs; i++) {
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struct dma_page_list *page_list = &pinned_list->page_list[i];
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for (j = 0; j < page_list->nr_pages; j++) {
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set_page_dirty_lock(page_list->pages[j]);
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page_cache_release(page_list->pages[j]);
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}
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}
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kfree(pinned_list);
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}
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static dma_cookie_t dma_memcpy_to_kernel_iovec(struct dma_chan *chan, struct
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iovec *iov, unsigned char *kdata, size_t len)
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{
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dma_cookie_t dma_cookie = 0;
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while (len > 0) {
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if (iov->iov_len) {
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int copy = min_t(unsigned int, iov->iov_len, len);
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dma_cookie = dma_async_memcpy_buf_to_buf(
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chan,
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iov->iov_base,
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kdata,
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copy);
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kdata += copy;
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len -= copy;
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iov->iov_len -= copy;
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iov->iov_base += copy;
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}
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iov++;
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}
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return dma_cookie;
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}
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/*
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* We have already pinned down the pages we will be using in the iovecs.
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* Each entry in iov array has corresponding entry in pinned_list->page_list.
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* Using array indexing to keep iov[] and page_list[] in sync.
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* Initial elements in iov array's iov->iov_len will be 0 if already copied into
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* by another call.
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* iov array length remaining guaranteed to be bigger than len.
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*/
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dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
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struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len)
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{
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int iov_byte_offset;
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int copy;
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dma_cookie_t dma_cookie = 0;
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int iovec_idx;
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int page_idx;
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if (!chan)
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return memcpy_toiovec(iov, kdata, len);
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/* -> kernel copies (e.g. smbfs) */
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if (!pinned_list)
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return dma_memcpy_to_kernel_iovec(chan, iov, kdata, len);
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iovec_idx = 0;
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while (iovec_idx < pinned_list->nr_iovecs) {
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struct dma_page_list *page_list;
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/* skip already used-up iovecs */
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while (!iov[iovec_idx].iov_len)
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iovec_idx++;
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page_list = &pinned_list->page_list[iovec_idx];
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iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
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page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
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- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
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/* break up copies to not cross page boundary */
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while (iov[iovec_idx].iov_len) {
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copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
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copy = min_t(int, copy, iov[iovec_idx].iov_len);
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dma_cookie = dma_async_memcpy_buf_to_pg(chan,
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page_list->pages[page_idx],
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iov_byte_offset,
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kdata,
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copy);
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len -= copy;
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iov[iovec_idx].iov_len -= copy;
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iov[iovec_idx].iov_base += copy;
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if (!len)
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return dma_cookie;
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kdata += copy;
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iov_byte_offset = 0;
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page_idx++;
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}
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iovec_idx++;
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}
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/* really bad if we ever run out of iovecs */
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BUG();
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return -EFAULT;
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}
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dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
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struct dma_pinned_list *pinned_list, struct page *page,
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unsigned int offset, size_t len)
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{
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int iov_byte_offset;
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int copy;
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dma_cookie_t dma_cookie = 0;
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int iovec_idx;
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int page_idx;
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int err;
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/* this needs as-yet-unimplemented buf-to-buff, so punt. */
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/* TODO: use dma for this */
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if (!chan || !pinned_list) {
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u8 *vaddr = kmap(page);
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err = memcpy_toiovec(iov, vaddr + offset, len);
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kunmap(page);
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return err;
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}
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iovec_idx = 0;
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while (iovec_idx < pinned_list->nr_iovecs) {
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struct dma_page_list *page_list;
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/* skip already used-up iovecs */
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while (!iov[iovec_idx].iov_len)
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iovec_idx++;
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page_list = &pinned_list->page_list[iovec_idx];
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iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
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page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
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- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
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/* break up copies to not cross page boundary */
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while (iov[iovec_idx].iov_len) {
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copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
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copy = min_t(int, copy, iov[iovec_idx].iov_len);
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dma_cookie = dma_async_memcpy_pg_to_pg(chan,
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page_list->pages[page_idx],
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iov_byte_offset,
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page,
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offset,
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copy);
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len -= copy;
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iov[iovec_idx].iov_len -= copy;
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iov[iovec_idx].iov_base += copy;
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if (!len)
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return dma_cookie;
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offset += copy;
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iov_byte_offset = 0;
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page_idx++;
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}
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iovec_idx++;
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}
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/* really bad if we ever run out of iovecs */
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BUG();
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return -EFAULT;
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}
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@ -333,5 +333,27 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
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int dma_async_device_register(struct dma_device *device);
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void dma_async_device_unregister(struct dma_device *device);
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/* --- Helper iov-locking functions --- */
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struct dma_page_list {
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char *base_address;
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int nr_pages;
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struct page **pages;
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};
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struct dma_pinned_list {
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int nr_iovecs;
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struct dma_page_list page_list[0];
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};
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struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len);
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void dma_unpin_iovec_pages(struct dma_pinned_list* pinned_list);
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dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
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struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len);
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dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
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struct dma_pinned_list *pinned_list, struct page *page,
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unsigned int offset, size_t len);
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#endif /* CONFIG_DMA_ENGINE */
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#endif /* DMAENGINE_H */
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@ -23,6 +23,7 @@
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#include <linux/config.h>
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#ifdef CONFIG_NET_DMA
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#include <linux/dmaengine.h>
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#include <linux/skbuff.h>
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static inline struct dma_chan *get_softnet_dma(void)
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{
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@ -34,5 +35,10 @@ static inline struct dma_chan *get_softnet_dma(void)
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rcu_read_unlock();
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return chan;
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}
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int dma_skb_copy_datagram_iovec(struct dma_chan* chan,
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const struct sk_buff *skb, int offset, struct iovec *to,
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size_t len, struct dma_pinned_list *pinned_list);
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#endif /* CONFIG_NET_DMA */
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#endif /* NETDMA_H */
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|
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@ -16,3 +16,4 @@ obj-$(CONFIG_NET_DIVERT) += dv.o
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obj-$(CONFIG_NET_PKTGEN) += pktgen.o
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obj-$(CONFIG_WIRELESS_EXT) += wireless.o
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obj-$(CONFIG_NETPOLL) += netpoll.o
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obj-$(CONFIG_NET_DMA) += user_dma.o
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|
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@ -0,0 +1,127 @@
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/*
|
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* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
|
||||
* Portions based on net/core/datagram.c and copyrighted by their authors.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify it
|
||||
* under the terms of the GNU General Public License as published by the Free
|
||||
* Software Foundation; either version 2 of the License, or (at your option)
|
||||
* any later version.
|
||||
*
|
||||
* This program is distributed in the hope that it will be useful, but WITHOUT
|
||||
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||||
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
||||
* more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License along with
|
||||
* this program; if not, write to the Free Software Foundation, Inc., 59
|
||||
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
||||
*
|
||||
* The full GNU General Public License is included in this distribution in the
|
||||
* file called COPYING.
|
||||
*/
|
||||
|
||||
/*
|
||||
* This code allows the net stack to make use of a DMA engine for
|
||||
* skb to iovec copies.
|
||||
*/
|
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|
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#include <linux/dmaengine.h>
|
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#include <linux/socket.h>
|
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#include <linux/rtnetlink.h> /* for BUG_TRAP */
|
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#include <net/tcp.h>
|
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|
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/**
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* dma_skb_copy_datagram_iovec - Copy a datagram to an iovec.
|
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* @skb - buffer to copy
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* @offset - offset in the buffer to start copying from
|
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* @iovec - io vector to copy to
|
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* @len - amount of data to copy from buffer to iovec
|
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* @pinned_list - locked iovec buffer data
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*
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* Note: the iovec is modified during the copy.
|
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*/
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int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
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struct sk_buff *skb, int offset, struct iovec *to,
|
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size_t len, struct dma_pinned_list *pinned_list)
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{
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int start = skb_headlen(skb);
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int i, copy = start - offset;
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dma_cookie_t cookie = 0;
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|
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/* Copy header. */
|
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if (copy > 0) {
|
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if (copy > len)
|
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copy = len;
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cookie = dma_memcpy_to_iovec(chan, to, pinned_list,
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skb->data + offset, copy);
|
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if (cookie < 0)
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goto fault;
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len -= copy;
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if (len == 0)
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goto end;
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offset += copy;
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}
|
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|
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/* Copy paged appendix. Hmm... why does this look so complicated? */
|
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for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
|
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int end;
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|
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BUG_TRAP(start <= offset + len);
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|
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end = start + skb_shinfo(skb)->frags[i].size;
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copy = end - offset;
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if ((copy = end - offset) > 0) {
|
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skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
|
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struct page *page = frag->page;
|
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|
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if (copy > len)
|
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copy = len;
|
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|
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cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page,
|
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frag->page_offset + offset - start, copy);
|
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if (cookie < 0)
|
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goto fault;
|
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len -= copy;
|
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if (len == 0)
|
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goto end;
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offset += copy;
|
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}
|
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start = end;
|
||||
}
|
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|
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if (skb_shinfo(skb)->frag_list) {
|
||||
struct sk_buff *list = skb_shinfo(skb)->frag_list;
|
||||
|
||||
for (; list; list = list->next) {
|
||||
int end;
|
||||
|
||||
BUG_TRAP(start <= offset + len);
|
||||
|
||||
end = start + list->len;
|
||||
copy = end - offset;
|
||||
if (copy > 0) {
|
||||
if (copy > len)
|
||||
copy = len;
|
||||
cookie = dma_skb_copy_datagram_iovec(chan, list,
|
||||
offset - start, to, copy,
|
||||
pinned_list);
|
||||
if (cookie < 0)
|
||||
goto fault;
|
||||
len -= copy;
|
||||
if (len == 0)
|
||||
goto end;
|
||||
offset += copy;
|
||||
}
|
||||
start = end;
|
||||
}
|
||||
}
|
||||
|
||||
end:
|
||||
if (!len) {
|
||||
skb->dma_cookie = cookie;
|
||||
return cookie;
|
||||
}
|
||||
|
||||
fault:
|
||||
return -EFAULT;
|
||||
}
|
||||
Reference in New Issue