From c13c8260da3155f2cefb63b0d1b7dcdcb405c644 Mon Sep 17 00:00:00 2001 From: Chris Leech Date: Tue, 23 May 2006 17:18:44 -0700 Subject: [I/OAT]: DMA memcpy subsystem Provides an API for offloading memory copies to DMA devices Signed-off-by: Chris Leech Signed-off-by: David S. Miller --- include/linux/dmaengine.h | 337 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 337 insertions(+) create mode 100644 include/linux/dmaengine.h (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h new file mode 100644 index 000000000000..30781546ac99 --- /dev/null +++ b/include/linux/dmaengine.h @@ -0,0 +1,337 @@ +/* + * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved. + * + * 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. + */ +#ifndef DMAENGINE_H +#define DMAENGINE_H +#include +#ifdef CONFIG_DMA_ENGINE + +#include +#include +#include +#include +#include + +/** + * enum dma_event - resource PNP/power managment events + * @DMA_RESOURCE_SUSPEND: DMA device going into low power state + * @DMA_RESOURCE_RESUME: DMA device returning to full power + * @DMA_RESOURCE_ADDED: DMA device added to the system + * @DMA_RESOURCE_REMOVED: DMA device removed from the system + */ +enum dma_event { + DMA_RESOURCE_SUSPEND, + DMA_RESOURCE_RESUME, + DMA_RESOURCE_ADDED, + DMA_RESOURCE_REMOVED, +}; + +/** + * typedef dma_cookie_t + * + * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code + */ +typedef s32 dma_cookie_t; + +#define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0) + +/** + * enum dma_status - DMA transaction status + * @DMA_SUCCESS: transaction completed successfully + * @DMA_IN_PROGRESS: transaction not yet processed + * @DMA_ERROR: transaction failed + */ +enum dma_status { + DMA_SUCCESS, + DMA_IN_PROGRESS, + DMA_ERROR, +}; + +/** + * struct dma_chan_percpu - the per-CPU part of struct dma_chan + * @refcount: local_t used for open-coded "bigref" counting + * @memcpy_count: transaction counter + * @bytes_transferred: byte counter + */ + +struct dma_chan_percpu { + local_t refcount; + /* stats */ + unsigned long memcpy_count; + unsigned long bytes_transferred; +}; + +/** + * struct dma_chan - devices supply DMA channels, clients use them + * @client: ptr to the client user of this chan, will be NULL when unused + * @device: ptr to the dma device who supplies this channel, always !NULL + * @cookie: last cookie value returned to client + * @chan_id: + * @class_dev: + * @refcount: kref, used in "bigref" slow-mode + * @slow_ref: + * @rcu: + * @client_node: used to add this to the client chan list + * @device_node: used to add this to the device chan list + * @local: per-cpu pointer to a struct dma_chan_percpu + */ +struct dma_chan { + struct dma_client *client; + struct dma_device *device; + dma_cookie_t cookie; + + /* sysfs */ + int chan_id; + struct class_device class_dev; + + struct kref refcount; + int slow_ref; + struct rcu_head rcu; + + struct list_head client_node; + struct list_head device_node; + struct dma_chan_percpu *local; +}; + +void dma_chan_cleanup(struct kref *kref); + +static inline void dma_chan_get(struct dma_chan *chan) +{ + if (unlikely(chan->slow_ref)) + kref_get(&chan->refcount); + else { + local_inc(&(per_cpu_ptr(chan->local, get_cpu())->refcount)); + put_cpu(); + } +} + +static inline void dma_chan_put(struct dma_chan *chan) +{ + if (unlikely(chan->slow_ref)) + kref_put(&chan->refcount, dma_chan_cleanup); + else { + local_dec(&(per_cpu_ptr(chan->local, get_cpu())->refcount)); + put_cpu(); + } +} + +/* + * typedef dma_event_callback - function pointer to a DMA event callback + */ +typedef void (*dma_event_callback) (struct dma_client *client, + struct dma_chan *chan, enum dma_event event); + +/** + * struct dma_client - info on the entity making use of DMA services + * @event_callback: func ptr to call when something happens + * @chan_count: number of chans allocated + * @chans_desired: number of chans requested. Can be +/- chan_count + * @lock: protects access to the channels list + * @channels: the list of DMA channels allocated + * @global_node: list_head for global dma_client_list + */ +struct dma_client { + dma_event_callback event_callback; + unsigned int chan_count; + unsigned int chans_desired; + + spinlock_t lock; + struct list_head channels; + struct list_head global_node; +}; + +/** + * struct dma_device - info on the entity supplying DMA services + * @chancnt: how many DMA channels are supported + * @channels: the list of struct dma_chan + * @global_node: list_head for global dma_device_list + * @refcount: + * @done: + * @dev_id: + * Other func ptrs: used to make use of this device's capabilities + */ +struct dma_device { + + unsigned int chancnt; + struct list_head channels; + struct list_head global_node; + + struct kref refcount; + struct completion done; + + int dev_id; + + int (*device_alloc_chan_resources)(struct dma_chan *chan); + void (*device_free_chan_resources)(struct dma_chan *chan); + dma_cookie_t (*device_memcpy_buf_to_buf)(struct dma_chan *chan, + void *dest, void *src, size_t len); + dma_cookie_t (*device_memcpy_buf_to_pg)(struct dma_chan *chan, + struct page *page, unsigned int offset, void *kdata, + size_t len); + dma_cookie_t (*device_memcpy_pg_to_pg)(struct dma_chan *chan, + struct page *dest_pg, unsigned int dest_off, + struct page *src_pg, unsigned int src_off, size_t len); + enum dma_status (*device_memcpy_complete)(struct dma_chan *chan, + dma_cookie_t cookie, dma_cookie_t *last, + dma_cookie_t *used); + void (*device_memcpy_issue_pending)(struct dma_chan *chan); +}; + +/* --- public DMA engine API --- */ + +struct dma_client *dma_async_client_register(dma_event_callback event_callback); +void dma_async_client_unregister(struct dma_client *client); +void dma_async_client_chan_request(struct dma_client *client, + unsigned int number); + +/** + * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses + * @chan: DMA channel to offload copy to + * @dest: destination address (virtual) + * @src: source address (virtual) + * @len: length + * + * Both @dest and @src must be mappable to a bus address according to the + * DMA mapping API rules for streaming mappings. + * Both @dest and @src must stay memory resident (kernel memory or locked + * user space pages) + */ +static inline dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan, + void *dest, void *src, size_t len) +{ + int cpu = get_cpu(); + per_cpu_ptr(chan->local, cpu)->bytes_transferred += len; + per_cpu_ptr(chan->local, cpu)->memcpy_count++; + put_cpu(); + + return chan->device->device_memcpy_buf_to_buf(chan, dest, src, len); +} + +/** + * dma_async_memcpy_buf_to_pg - offloaded copy + * @chan: DMA channel to offload copy to + * @page: destination page + * @offset: offset in page to copy to + * @kdata: source address (virtual) + * @len: length + * + * Both @page/@offset and @kdata must be mappable to a bus address according + * to the DMA mapping API rules for streaming mappings. + * Both @page/@offset and @kdata must stay memory resident (kernel memory or + * locked user space pages) + */ +static inline dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan, + struct page *page, unsigned int offset, void *kdata, size_t len) +{ + int cpu = get_cpu(); + per_cpu_ptr(chan->local, cpu)->bytes_transferred += len; + per_cpu_ptr(chan->local, cpu)->memcpy_count++; + put_cpu(); + + return chan->device->device_memcpy_buf_to_pg(chan, page, offset, + kdata, len); +} + +/** + * dma_async_memcpy_buf_to_pg - offloaded copy + * @chan: DMA channel to offload copy to + * @dest_page: destination page + * @dest_off: offset in page to copy to + * @src_page: source page + * @src_off: offset in page to copy from + * @len: length + * + * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus + * address according to the DMA mapping API rules for streaming mappings. + * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident + * (kernel memory or locked user space pages) + */ +static inline dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan, + struct page *dest_pg, unsigned int dest_off, struct page *src_pg, + unsigned int src_off, size_t len) +{ + int cpu = get_cpu(); + per_cpu_ptr(chan->local, cpu)->bytes_transferred += len; + per_cpu_ptr(chan->local, cpu)->memcpy_count++; + put_cpu(); + + return chan->device->device_memcpy_pg_to_pg(chan, dest_pg, dest_off, + src_pg, src_off, len); +} + +/** + * dma_async_memcpy_issue_pending - flush pending copies to HW + * @chan: + * + * This allows drivers to push copies to HW in batches, + * reducing MMIO writes where possible. + */ +static inline void dma_async_memcpy_issue_pending(struct dma_chan *chan) +{ + return chan->device->device_memcpy_issue_pending(chan); +} + +/** + * dma_async_memcpy_complete - poll for transaction completion + * @chan: DMA channel + * @cookie: transaction identifier to check status of + * @last: returns last completed cookie, can be NULL + * @used: returns last issued cookie, can be NULL + * + * If @last and @used are passed in, upon return they reflect the driver + * internal state and can be used with dma_async_is_complete() to check + * the status of multiple cookies without re-checking hardware state. + */ +static inline enum dma_status dma_async_memcpy_complete(struct dma_chan *chan, + dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used) +{ + return chan->device->device_memcpy_complete(chan, cookie, last, used); +} + +/** + * dma_async_is_complete - test a cookie against chan state + * @cookie: transaction identifier to test status of + * @last_complete: last know completed transaction + * @last_used: last cookie value handed out + * + * dma_async_is_complete() is used in dma_async_memcpy_complete() + * the test logic is seperated for lightweight testing of multiple cookies + */ +static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie, + dma_cookie_t last_complete, dma_cookie_t last_used) +{ + if (last_complete <= last_used) { + if ((cookie <= last_complete) || (cookie > last_used)) + return DMA_SUCCESS; + } else { + if ((cookie <= last_complete) && (cookie > last_used)) + return DMA_SUCCESS; + } + return DMA_IN_PROGRESS; +} + + +/* --- DMA device --- */ + +int dma_async_device_register(struct dma_device *device); +void dma_async_device_unregister(struct dma_device *device); + +#endif /* CONFIG_DMA_ENGINE */ +#endif /* DMAENGINE_H */ -- cgit v1.2.3 From de5506e155276d385712c2aa1c2d9a27cd4ed947 Mon Sep 17 00:00:00 2001 From: Chris Leech Date: Tue, 23 May 2006 17:50:37 -0700 Subject: [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 Signed-off-by: David S. Miller --- drivers/dma/Makefile | 3 +- drivers/dma/iovlock.c | 301 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dmaengine.h | 22 ++++ include/net/netdma.h | 6 + net/core/Makefile | 1 + net/core/user_dma.c | 127 +++++++++++++++++++ 6 files changed, 459 insertions(+), 1 deletion(-) create mode 100644 drivers/dma/iovlock.c create mode 100644 net/core/user_dma.c (limited to 'include/linux/dmaengine.h') diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile index c8a5f5677313..bdcfdbdb1aec 100644 --- a/drivers/dma/Makefile +++ b/drivers/dma/Makefile @@ -1,2 +1,3 @@ -obj-y += dmaengine.o +obj-$(CONFIG_DMA_ENGINE) += dmaengine.o +obj-$(CONFIG_NET_DMA) += iovlock.o obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o diff --git a/drivers/dma/iovlock.c b/drivers/dma/iovlock.c new file mode 100644 index 000000000000..5ed327e453a2 --- /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 + +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; +} diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 30781546ac99..78b236ca04f8 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -333,5 +333,27 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie, int dma_async_device_register(struct dma_device *device); void dma_async_device_unregister(struct dma_device *device); +/* --- Helper iov-locking functions --- */ + +struct dma_page_list { + char *base_address; + int nr_pages; + struct page **pages; +}; + +struct dma_pinned_list { + int nr_iovecs; + struct dma_page_list page_list[0]; +}; + +struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len); +void dma_unpin_iovec_pages(struct dma_pinned_list* pinned_list); + +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); +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); + #endif /* CONFIG_DMA_ENGINE */ #endif /* DMAENGINE_H */ diff --git a/include/net/netdma.h b/include/net/netdma.h index cbfe89d7e5d0..19760eb131aa 100644 --- a/include/net/netdma.h +++ b/include/net/netdma.h @@ -23,6 +23,7 @@ #include #ifdef CONFIG_NET_DMA #include +#include static inline struct dma_chan *get_softnet_dma(void) { @@ -34,5 +35,10 @@ static inline struct dma_chan *get_softnet_dma(void) rcu_read_unlock(); return chan; } + +int dma_skb_copy_datagram_iovec(struct dma_chan* chan, + const struct sk_buff *skb, int offset, struct iovec *to, + size_t len, struct dma_pinned_list *pinned_list); + #endif /* CONFIG_NET_DMA */ #endif /* NETDMA_H */ diff --git a/net/core/Makefile b/net/core/Makefile index 79fe12cced27..e9bd2467d5a9 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -16,3 +16,4 @@ obj-$(CONFIG_NET_DIVERT) += dv.o obj-$(CONFIG_NET_PKTGEN) += pktgen.o obj-$(CONFIG_WIRELESS_EXT) += wireless.o obj-$(CONFIG_NETPOLL) += netpoll.o +obj-$(CONFIG_NET_DMA) += user_dma.o diff --git a/net/core/user_dma.c b/net/core/user_dma.c new file mode 100644 index 000000000000..9eee91bcbf3f --- /dev/null +++ b/net/core/user_dma.c @@ -0,0 +1,127 @@ +/* + * 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 BUG_TRAP */ +#include + +/** + * dma_skb_copy_datagram_iovec - Copy a datagram to an iovec. + * @skb - buffer to copy + * @offset - offset in the buffer to start copying from + * @iovec - io vector to copy to + * @len - amount of data to copy from buffer to iovec + * @pinned_list - locked iovec buffer data + * + * Note: the iovec is modified during the copy. + */ +int dma_skb_copy_datagram_iovec(struct dma_chan *chan, + struct sk_buff *skb, int offset, struct iovec *to, + size_t len, struct dma_pinned_list *pinned_list) +{ + int start = skb_headlen(skb); + int i, copy = start - offset; + dma_cookie_t cookie = 0; + + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + cookie = dma_memcpy_to_iovec(chan, to, pinned_list, + skb->data + offset, copy); + if (cookie < 0) + goto fault; + len -= copy; + if (len == 0) + goto end; + offset += copy; + } + + /* Copy paged appendix. Hmm... why does this look so complicated? */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; + + BUG_TRAP(start <= offset + len); + + end = start + skb_shinfo(skb)->frags[i].size; + copy = end - offset; + if ((copy = end - offset) > 0) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + struct page *page = frag->page; + + if (copy > len) + copy = len; + + cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page, + frag->page_offset + offset - start, copy); + if (cookie < 0) + goto fault; + len -= copy; + if (len == 0) + goto end; + offset += copy; + } + start = end; + } + + 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; +} -- cgit v1.2.3