X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fdma%2Fiovlock.c;fp=drivers%2Fdma%2Fiovlock.c;h=d637555a833b78870f2f19da130d54d93e0d2f96;hb=f05f9504c50ed069377d37f02f22e7a16b5921de;hp=0000000000000000000000000000000000000000;hpb=16c70f8c1b54b61c3b951b6fb220df250fe09b32;p=linux-2.6.git diff --git a/drivers/dma/iovlock.c b/drivers/dma/iovlock.c new file mode 100644 index 000000000..d637555a8 --- /dev/null +++ b/drivers/dma/iovlock.c @@ -0,0 +1,301 @@ +/* + * 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. + */ + +#include +#include +#include /* for memcpy_toiovec */ +#include +#include + +static int num_pages_spanned(struct iovec *iov) +{ + return + ((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) - + ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT); +} + +/* + * Pin down all the iovec pages needed for len bytes. + * Return a struct dma_pinned_list to keep track of pages pinned down. + * + * We are allocating a single chunk of memory, and then carving it up into + * 3 sections, the latter 2 whose size depends on the number of iovecs and the + * total number of pages, respectively. + */ +struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len) +{ + struct dma_pinned_list *local_list; + struct page **pages; + int i; + int ret; + int nr_iovecs = 0; + int iovec_len_used = 0; + int iovec_pages_used = 0; + long err; + + /* don't pin down non-user-based iovecs */ + if (segment_eq(get_fs(), KERNEL_DS)) + return NULL; + + /* determine how many iovecs/pages there are, up front */ + do { + iovec_len_used += iov[nr_iovecs].iov_len; + iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]); + nr_iovecs++; + } while (iovec_len_used < len); + + /* single kmalloc for pinned list, page_list[], and the page arrays */ + local_list = kmalloc(sizeof(*local_list) + + (nr_iovecs * sizeof (struct dma_page_list)) + + (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL); + if (!local_list) { + err = -ENOMEM; + goto out; + } + + /* list of pages starts right after the page list array */ + pages = (struct page **) &local_list->page_list[nr_iovecs]; + + for (i = 0; i < nr_iovecs; i++) { + struct dma_page_list *page_list = &local_list->page_list[i]; + + len -= iov[i].iov_len; + + if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len)) { + err = -EFAULT; + goto unpin; + } + + page_list->nr_pages = num_pages_spanned(&iov[i]); + page_list->base_address = iov[i].iov_base; + + page_list->pages = pages; + pages += page_list->nr_pages; + + /* pin pages down */ + down_read(¤t->mm->mmap_sem); + ret = get_user_pages( + current, + current->mm, + (unsigned long) iov[i].iov_base, + page_list->nr_pages, + 1, /* write */ + 0, /* force */ + page_list->pages, + NULL); + up_read(¤t->mm->mmap_sem); + + if (ret != page_list->nr_pages) { + err = -ENOMEM; + goto unpin; + } + + local_list->nr_iovecs = i + 1; + } + + return local_list; + +unpin: + dma_unpin_iovec_pages(local_list); +out: + return ERR_PTR(err); +} + +void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list) +{ + int i, j; + + if (!pinned_list) + return; + + for (i = 0; i < pinned_list->nr_iovecs; i++) { + struct dma_page_list *page_list = &pinned_list->page_list[i]; + for (j = 0; j < page_list->nr_pages; j++) { + set_page_dirty_lock(page_list->pages[j]); + page_cache_release(page_list->pages[j]); + } + } + + kfree(pinned_list); +} + +static dma_cookie_t dma_memcpy_to_kernel_iovec(struct dma_chan *chan, struct + iovec *iov, unsigned char *kdata, size_t len) +{ + dma_cookie_t dma_cookie = 0; + + while (len > 0) { + if (iov->iov_len) { + int copy = min_t(unsigned int, iov->iov_len, len); + dma_cookie = dma_async_memcpy_buf_to_buf( + chan, + iov->iov_base, + kdata, + copy); + kdata += copy; + len -= copy; + iov->iov_len -= copy; + iov->iov_base += copy; + } + iov++; + } + + return dma_cookie; +} + +/* + * We have already pinned down the pages we will be using in the iovecs. + * Each entry in iov array has corresponding entry in pinned_list->page_list. + * Using array indexing to keep iov[] and page_list[] in sync. + * Initial elements in iov array's iov->iov_len will be 0 if already copied into + * by another call. + * iov array length remaining guaranteed to be bigger than len. + */ +dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov, + struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len) +{ + int iov_byte_offset; + int copy; + dma_cookie_t dma_cookie = 0; + int iovec_idx; + int page_idx; + + if (!chan) + return memcpy_toiovec(iov, kdata, len); + + /* -> kernel copies (e.g. smbfs) */ + if (!pinned_list) + return dma_memcpy_to_kernel_iovec(chan, iov, kdata, len); + + iovec_idx = 0; + while (iovec_idx < pinned_list->nr_iovecs) { + struct dma_page_list *page_list; + + /* skip already used-up iovecs */ + while (!iov[iovec_idx].iov_len) + iovec_idx++; + + page_list = &pinned_list->page_list[iovec_idx]; + + iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK); + page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK) + - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT; + + /* break up copies to not cross page boundary */ + while (iov[iovec_idx].iov_len) { + copy = min_t(int, PAGE_SIZE - iov_byte_offset, len); + copy = min_t(int, copy, iov[iovec_idx].iov_len); + + dma_cookie = dma_async_memcpy_buf_to_pg(chan, + page_list->pages[page_idx], + iov_byte_offset, + kdata, + copy); + + len -= copy; + iov[iovec_idx].iov_len -= copy; + iov[iovec_idx].iov_base += copy; + + if (!len) + return dma_cookie; + + kdata += copy; + iov_byte_offset = 0; + page_idx++; + } + iovec_idx++; + } + + /* really bad if we ever run out of iovecs */ + BUG(); + return -EFAULT; +} + +dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov, + struct dma_pinned_list *pinned_list, struct page *page, + unsigned int offset, size_t len) +{ + int iov_byte_offset; + int copy; + dma_cookie_t dma_cookie = 0; + int iovec_idx; + int page_idx; + int err; + + /* this needs as-yet-unimplemented buf-to-buff, so punt. */ + /* TODO: use dma for this */ + if (!chan || !pinned_list) { + u8 *vaddr = kmap(page); + err = memcpy_toiovec(iov, vaddr + offset, len); + kunmap(page); + return err; + } + + iovec_idx = 0; + while (iovec_idx < pinned_list->nr_iovecs) { + struct dma_page_list *page_list; + + /* skip already used-up iovecs */ + while (!iov[iovec_idx].iov_len) + iovec_idx++; + + page_list = &pinned_list->page_list[iovec_idx]; + + iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK); + page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK) + - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT; + + /* break up copies to not cross page boundary */ + while (iov[iovec_idx].iov_len) { + copy = min_t(int, PAGE_SIZE - iov_byte_offset, len); + copy = min_t(int, copy, iov[iovec_idx].iov_len); + + dma_cookie = dma_async_memcpy_pg_to_pg(chan, + page_list->pages[page_idx], + iov_byte_offset, + page, + offset, + copy); + + len -= copy; + iov[iovec_idx].iov_len -= copy; + iov[iovec_idx].iov_base += copy; + + if (!len) + return dma_cookie; + + offset += copy; + iov_byte_offset = 0; + page_idx++; + } + iovec_idx++; + } + + /* really bad if we ever run out of iovecs */ + BUG(); + return -EFAULT; +}