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https://github.com/openvswitch/ovs
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2c272bd98f
This is the ported version of commit 36d5fe6a with the same name from net-next. Apart from the small datapath.c changes it adjust the compat layer files as well. This is the original commit message: "skb_zerocopy can copy elements of the frags array between skbs, but it doesn't orphan them. Also, it doesn't handle errors, so this patch takes care of that as well, and modify the callers accordingly. skb_tx_error() is also added to the callers so they will signal the failed delivery towards the creator of the skb." Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Signed-off-by: Jesse Gross <jesse@nicira.com>
125 lines
2.9 KiB
C
125 lines
2.9 KiB
C
#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#if !defined(HAVE_SKB_WARN_LRO) && defined(NETIF_F_LRO)
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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void __skb_warn_lro_forwarding(const struct sk_buff *skb)
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{
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if (net_ratelimit())
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pr_warn("%s: received packets cannot be forwarded while LRO is enabled\n",
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skb->dev->name);
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}
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#endif
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#if LINUX_VERSION_CODE < KERNEL_VERSION(3,14,0)
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static inline bool head_frag(const struct sk_buff *skb)
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{
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#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,5,0)
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return skb->head_frag;
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#else
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return false;
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#endif
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}
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/**
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* skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
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* @from: source buffer
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*
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* Calculates the amount of linear headroom needed in the 'to' skb passed
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* into skb_zerocopy().
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*/
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unsigned int
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skb_zerocopy_headlen(const struct sk_buff *from)
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{
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unsigned int hlen = 0;
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if (!head_frag(from) ||
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skb_headlen(from) < L1_CACHE_BYTES ||
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skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
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hlen = skb_headlen(from);
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if (skb_has_frag_list(from))
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hlen = from->len;
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return hlen;
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}
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/**
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* skb_zerocopy - Zero copy skb to skb
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* @to: destination buffer
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* @source: source buffer
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* @len: number of bytes to copy from source buffer
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* @hlen: size of linear headroom in destination buffer
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*
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* Copies up to `len` bytes from `from` to `to` by creating references
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* to the frags in the source buffer.
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*
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* The `hlen` as calculated by skb_zerocopy_headlen() specifies the
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* headroom in the `to` buffer.
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*
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* Return value:
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* 0: everything is OK
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* -ENOMEM: couldn't orphan frags of @from due to lack of memory
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* -EFAULT: skb_copy_bits() found some problem with skb geometry
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*/
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int
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skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
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{
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int i, j = 0;
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int plen = 0; /* length of skb->head fragment */
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int ret;
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struct page *page;
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unsigned int offset;
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BUG_ON(!head_frag(from) && !hlen);
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/* dont bother with small payloads */
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if (len <= skb_tailroom(to))
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return skb_copy_bits(from, 0, skb_put(to, len), len);
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if (hlen) {
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ret = skb_copy_bits(from, 0, skb_put(to, hlen), hlen);
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if (unlikely(ret))
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return ret;
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len -= hlen;
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} else {
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plen = min_t(int, skb_headlen(from), len);
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if (plen) {
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page = virt_to_head_page(from->head);
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offset = from->data - (unsigned char *)page_address(page);
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__skb_fill_page_desc(to, 0, page, offset, plen);
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get_page(page);
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j = 1;
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len -= plen;
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}
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}
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to->truesize += len + plen;
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to->len += len + plen;
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to->data_len += len + plen;
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if (unlikely(skb_orphan_frags(from, GFP_ATOMIC))) {
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skb_tx_error(from);
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return -ENOMEM;
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}
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for (i = 0; i < skb_shinfo(from)->nr_frags; i++) {
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if (!len)
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break;
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skb_shinfo(to)->frags[j] = skb_shinfo(from)->frags[i];
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skb_shinfo(to)->frags[j].size = min_t(int, skb_shinfo(to)->frags[j].size, len);
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len -= skb_shinfo(to)->frags[j].size;
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skb_frag_ref(to, j);
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j++;
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}
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skb_shinfo(to)->nr_frags = j;
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return 0;
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}
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#endif
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