diff --git a/net/core/Makefile b/net/core/Makefile
index 630da0f..d02132b 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -8,7 +8,8 @@ obj-y := sock.o request_sock.o skbuff.o
obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
obj-y += dev.o ethtool.o dev_mcast.o dst.o \
- neighbour.o rtnetlink.o utils.o link_watch.o filter.o
+ neighbour.o rtnetlink.o utils.o link_watch.o filter.o \
+ user_dma.o
obj-$(CONFIG_XFRM) += flow.o
obj-$(CONFIG_SYSFS) += net-sysfs.o
diff --git a/net/core/dev.c b/net/core/dev.c
index a44eeef..a81bee8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -113,6 +113,7 @@
#include <linux/wireless.h> /* Note : will define WIRELESS_EXT */
#include <net/iw_handler.h>
#endif /* CONFIG_NET_RADIO */
+#include <linux/dmaengine.h>
#include <asm/current.h>
/*
@@ -147,6 +148,12 @@ static DEFINE_SPINLOCK(ptype_lock);
static struct list_head ptype_base[16]; /* 16 way hashed list */
static struct list_head ptype_all; /* Taps */
+#ifdef CONFIG_NET_DMA
+struct dma_client *net_dma_client;
+DEFINE_PER_CPU(struct dma_chan *, net_dma);
+static unsigned int net_dma_count;
+#endif
+
/*
* The @dev_base list is protected by @dev_base_lock and the rtln
* semaphore.
@@ -1708,6 +1715,9 @@ static void net_rx_action(struct softirq
unsigned long start_time = jiffies;
int budget = netdev_budget;
void *have;
+#ifdef CONFIG_NET_DMA
+ struct dma_chan *chan;
+#endif
local_irq_disable();
@@ -1739,6 +1749,10 @@ static void net_rx_action(struct softirq
}
}
out:
+#ifdef CONFIG_NET_DMA
+ list_for_each_entry(chan, &net_dma_client->channels, client_node)
+ dma_async_memcpy_issue_pending(chan);
+#endif
local_irq_enable();
return;
@@ -3171,6 +3185,68 @@ static int dev_cpu_callback(struct notif
}
#endif /* CONFIG_HOTPLUG_CPU */
+#ifdef CONFIG_NET_DMA
+static void net_dma_rebalance(void)
+{
+ unsigned int cpu, i, n;
+ struct dma_chan *chan;
+
+ lock_cpu_hotplug();
+
+ if (net_dma_count == 0) {
+ for_each_online_cpu(cpu)
+ per_cpu(net_dma, cpu) = NULL;
+ unlock_cpu_hotplug();
+ return;
+ }
+
+ i = 0;
+ cpu = first_cpu(cpu_online_map);
+
+ list_for_each_entry(chan, &net_dma_client->channels, client_node) {
+ /* cpus_clear(chan->cpumask); */
+ n = ((num_online_cpus() / net_dma_count) + (i < (num_online_cpus() % net_dma_count) ? 1 : 0));
+
+ while(n) {
+ per_cpu(net_dma, cpu) = chan;
+ /* cpu_set(cpu, chan->cpumask); */
+ cpu = next_cpu(cpu, cpu_online_map);
+ n--;
+ }
+ i++;
+ }
+
+ unlock_cpu_hotplug();
+}
+
+static void netdev_dma_event(struct dma_client *client, struct dma_chan *chan, enum dma_event_t event)
+{
+ switch (event) {
+ case DMA_RESOURCE_ADDED:
+ net_dma_count++;
+ net_dma_rebalance();
+ break;
+ case DMA_RESOURCE_REMOVED:
+ net_dma_count--;
+ net_dma_rebalance();
+ break;
+ default:
+ break;
+ }
+}
+
+static int __init netdev_dma_register(void)
+{
+ net_dma_client = dma_async_client_register(netdev_dma_event);
+
+ dma_async_client_chan_request(net_dma_client, num_online_cpus());
+
+ return 0;
+}
+
+#else
+static int __init netdev_dma_register(void) { return -ENODEV; }
+#endif /* CONFIG_NET_DMA */
/*
* Initialize the DEV module. At boot time this walks the device list and
@@ -3224,6 +3300,8 @@ static int __init net_dev_init(void)
atomic_set(&queue->backlog_dev.refcnt, 1);
}
+ netdev_dma_register();
+
dev_boot_phase = 0;
open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
diff --git a/net/core/user_dma.c b/net/core/user_dma.c
new file mode 100644
index 0000000..958e2c8
--- /dev/null
+++ b/net/core/user_dma.c
@@ -0,0 +1,422 @@
+/*
+ Copyright(c) 2004 - 2005 Intel Corporation
+ Portions based on net/core/datagram.c and copyrighted by their authors.
+
+ This code allows the net stack to make use of a DMA engine for
+ skb to iovec copies.
+*/
+
+#include <linux/dmaengine.h>
+#include <linux/pagemap.h>
+#include <linux/socket.h>
+#include <linux/rtnetlink.h> /* for BUG_TRAP */
+#include <net/tcp.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_NET_DMA
+
+#define NUM_PAGES_SPANNED(start, length) \
+ ((PAGE_ALIGN((unsigned long)start + length) - \
+ ((unsigned long)start & PAGE_MASK)) >> PAGE_SHIFT)
+
+/*
+ * Lock down all the iovec pages needed for len bytes.
+ * Return a struct dma_locked_list to keep track of pages locked 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.
+ */
+int
+dma_lock_iovec_pages(struct iovec *iov, size_t len, struct dma_locked_list **locked_list)
+{
+ struct dma_locked_list *local_list;
+ struct page **pages;
+ int i;
+ int ret;
+
+ int nr_iovecs = 0;
+ int iovec_len_used = 0;
+ int iovec_pages_used = 0;
+
+ /* don't lock down non-user-based iovecs */
+ if (segment_eq(get_fs(), KERNEL_DS)) {
+ *locked_list = NULL;
+ return 0;
+ }
+
+ /* 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].iov_base,
+ iov[nr_iovecs].iov_len);
+ nr_iovecs++;
+ } while (iovec_len_used < len);
+
+ /* single kmalloc for locked 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)
+ return -ENOMEM;
+
+ /* list of pages starts right after the page list array */
+ pages = (struct page **) &local_list->page_list[nr_iovecs];
+
+ /* it's a userspace pointer */
+ might_sleep();
+
+ 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)) {
+ dma_unlock_iovec_pages(local_list);
+ return -EFAULT;
+ }
+
+ page_list->nr_pages = NUM_PAGES_SPANNED(iov[i].iov_base, iov[i].iov_len);
+ page_list->base_address = iov[i].iov_base;
+
+ page_list->pages = pages;
+ pages += page_list->nr_pages;
+
+ /* lock 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,
+ 0,
+ page_list->pages,
+ NULL);
+ up_read(¤t->mm->mmap_sem);
+
+ if (ret != page_list->nr_pages) {
+ goto mem_error;
+ }
+
+ local_list->nr_iovecs = i + 1;
+ }
+
+ *locked_list = local_list;
+ return 0;
+
+mem_error:
+ dma_unlock_iovec_pages(local_list);
+ return -ENOMEM;
+}
+
+void
+dma_unlock_iovec_pages(struct dma_locked_list *locked_list)
+{
+ int i, j;
+
+ if (!locked_list)
+ return;
+
+ for (i = 0; i < locked_list->nr_iovecs; i++) {
+ struct dma_page_list *page_list = &locked_list->page_list[i];
+ for (j = 0; j < page_list->nr_pages; j++) {
+ SetPageDirty(page_list->pages[j]);
+ page_cache_release(page_list->pages[j]);
+ }
+ }
+
+ kfree(locked_list);
+}
+
+static dma_cookie_t
+dma_memcpy_tokerneliovec(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 locked down the pages we will be using in the iovecs.
+ * Each entry in iov array has corresponding entry in locked_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.
+ */
+static dma_cookie_t
+dma_memcpy_toiovec(struct dma_chan *chan, struct iovec *iov,
+ struct dma_locked_list *locked_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 (!locked_list)
+ return dma_memcpy_tokerneliovec(chan, iov, kdata, len);
+
+ iovec_idx = 0;
+ while (iovec_idx < locked_list->nr_iovecs) {
+ struct dma_page_list *page_list;
+
+ /* skip already used-up iovecs */
+ while (!iov[iovec_idx].iov_len)
+ iovec_idx++;
+
+ page_list = &locked_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;
+}
+
+static dma_cookie_t
+dma_memcpy_pg_toiovec(struct dma_chan *chan, struct iovec *iov,
+ struct dma_locked_list *locked_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 || !locked_list) {
+ u8 *vaddr = kmap(page);
+ err = memcpy_toiovec(iov, vaddr + offset, len);
+ kunmap(page);
+ return err;
+ }
+
+ iovec_idx = 0;
+ while (iovec_idx < locked_list->nr_iovecs) {
+ struct dma_page_list *page_list;
+
+ /* skip already used-up iovecs */
+ while (!iov[iovec_idx].iov_len)
+ iovec_idx++;
+
+ page_list = &locked_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;
+}
+
+void
+dma_memcpy_toiovec_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{
+ if (cookie <= 0)
+ return;
+
+ dma_async_wait_for_completion(chan, cookie);
+}
+
+/**
+ * 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
+ * @locked_list - locked iovec buffer data
+ *
+ * Note: the iovec is modified during the copy.
+ */
+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_locked_list *locked_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;
+ if ((cookie = dma_memcpy_toiovec(chan, to, locked_list,
+ skb->data + offset, copy)) < 0)
+ goto fault;
+ if ((len -= copy) == 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;
+ 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_toiovec(chan, to, locked_list, page,
+ frag->page_offset + offset - start, copy);
+ if (cookie < 0)
+ goto fault;
+ if (!(len -= copy))
+ 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;
+ if ((copy = end - offset) > 0) {
+ if (copy > len)
+ copy = len;
+ if ((cookie = dma_skb_copy_datagram_iovec(chan, list,
+ offset - start, to, copy, locked_list)) < 0)
+ goto fault;
+ if ((len -= copy) == 0)
+ goto end;
+ offset += copy;
+ }
+ start = end;
+ }
+ }
+
+end:
+ if (!len) {
+#if 0
+ TCP_SKB_CB(skb)->dma_cookie = cookie;
+#endif
+ return cookie;
+ }
+
+fault:
+ return -EFAULT;
+}
+
+#else
+
+int
+dma_lock_iovec_pages(struct iovec *iov, size_t len, struct dma_locked_list **locked_list)
+{
+ *locked_list = NULL;
+
+ return 0;
+}
+
+void
+dma_unlock_iovec_pages(struct dma_locked_list* locked_list)
+{ }
+
+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_locked_list *locked_list)
+{
+ return skb_copy_datagram_iovec(skb, offset, to, len);
+}
+
+void
+dma_memcpy_toiovec_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{ }
+
+#endif
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