From: Jason Wang Date: Tue, 6 Aug 2013 09:45:04 +0000 (+0800) Subject: net: move zerocopy_sg_from_iovec() to net/core/datagram.c X-Git-Tag: v3.12-rc1~132^2~333 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c3bdeb5c7cc073ccf5ff9624642022a8613a956e;p=platform%2Fkernel%2Flinux-stable.git net: move zerocopy_sg_from_iovec() to net/core/datagram.c To let it be reused and reduce code duplication. Also document this function. Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index dfec20d..182364a 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -536,86 +536,6 @@ static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, return skb; } -/* set skb frags from iovec, this can move to core network code for reuse */ -static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, - int offset, size_t count) -{ - int len = iov_length(from, count) - offset; - int copy = skb_headlen(skb); - int size, offset1 = 0; - int i = 0; - - /* Skip over from offset */ - while (count && (offset >= from->iov_len)) { - offset -= from->iov_len; - ++from; - --count; - } - - /* copy up to skb headlen */ - while (count && (copy > 0)) { - size = min_t(unsigned int, copy, from->iov_len - offset); - if (copy_from_user(skb->data + offset1, from->iov_base + offset, - size)) - return -EFAULT; - if (copy > size) { - ++from; - --count; - offset = 0; - } else - offset += size; - copy -= size; - offset1 += size; - } - - if (len == offset1) - return 0; - - while (count--) { - struct page *page[MAX_SKB_FRAGS]; - int num_pages; - unsigned long base; - unsigned long truesize; - - len = from->iov_len - offset; - if (!len) { - offset = 0; - ++from; - continue; - } - base = (unsigned long)from->iov_base + offset; - size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; - if (i + size > MAX_SKB_FRAGS) - return -EMSGSIZE; - num_pages = get_user_pages_fast(base, size, 0, &page[i]); - if (num_pages != size) { - int j; - - for (j = 0; j < num_pages; j++) - put_page(page[i + j]); - return -EFAULT; - } - truesize = size * PAGE_SIZE; - skb->data_len += len; - skb->len += len; - skb->truesize += truesize; - atomic_add(truesize, &skb->sk->sk_wmem_alloc); - while (len) { - int off = base & ~PAGE_MASK; - int size = min_t(int, len, PAGE_SIZE - off); - __skb_fill_page_desc(skb, i, page[i], off, size); - skb_shinfo(skb)->nr_frags++; - /* increase sk_wmem_alloc */ - base += size; - len -= size; - i++; - } - offset = 0; - ++from; - } - return 0; -} - /* * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should * be shared with the tun/tap driver. diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 18527ef..b163047 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -961,86 +961,6 @@ static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, return skb; } -/* set skb frags from iovec, this can move to core network code for reuse */ -static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, - int offset, size_t count) -{ - int len = iov_length(from, count) - offset; - int copy = skb_headlen(skb); - int size, offset1 = 0; - int i = 0; - - /* Skip over from offset */ - while (count && (offset >= from->iov_len)) { - offset -= from->iov_len; - ++from; - --count; - } - - /* copy up to skb headlen */ - while (count && (copy > 0)) { - size = min_t(unsigned int, copy, from->iov_len - offset); - if (copy_from_user(skb->data + offset1, from->iov_base + offset, - size)) - return -EFAULT; - if (copy > size) { - ++from; - --count; - offset = 0; - } else - offset += size; - copy -= size; - offset1 += size; - } - - if (len == offset1) - return 0; - - while (count--) { - struct page *page[MAX_SKB_FRAGS]; - int num_pages; - unsigned long base; - unsigned long truesize; - - len = from->iov_len - offset; - if (!len) { - offset = 0; - ++from; - continue; - } - base = (unsigned long)from->iov_base + offset; - size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; - if (i + size > MAX_SKB_FRAGS) - return -EMSGSIZE; - num_pages = get_user_pages_fast(base, size, 0, &page[i]); - if (num_pages != size) { - int j; - - for (j = 0; j < num_pages; j++) - put_page(page[i + j]); - return -EFAULT; - } - truesize = size * PAGE_SIZE; - skb->data_len += len; - skb->len += len; - skb->truesize += truesize; - atomic_add(truesize, &skb->sk->sk_wmem_alloc); - while (len) { - int off = base & ~PAGE_MASK; - int size = min_t(int, len, PAGE_SIZE - off); - __skb_fill_page_desc(skb, i, page[i], off, size); - skb_shinfo(skb)->nr_frags++; - /* increase sk_wmem_alloc */ - base += size; - len -= size; - i++; - } - offset = 0; - ++from; - } - return 0; -} - /* Get packet from user space buffer */ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, void *msg_control, const struct iovec *iv, diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index ae46475..5ac96f3 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2359,6 +2359,10 @@ extern int skb_copy_datagram_from_iovec(struct sk_buff *skb, const struct iovec *from, int from_offset, int len); +extern int zerocopy_sg_from_iovec(struct sk_buff *skb, + const struct iovec *frm, + int offset, + size_t count); extern int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset, const struct iovec *to, diff --git a/net/core/datagram.c b/net/core/datagram.c index 8ab48cd..f987fae 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -573,6 +573,99 @@ fault: } EXPORT_SYMBOL(skb_copy_datagram_from_iovec); +/** + * zerocopy_sg_from_iovec - Build a zerocopy datagram from an iovec + * @skb: buffer to copy + * @from: io vector to copy to + * @offset: offset in the io vector to start copying from + * @count: amount of vectors to copy to buffer from + * + * The function will first copy up to headlen, and then pin the userspace + * pages and build frags through them. + * + * Returns 0, -EFAULT or -EMSGSIZE. + * Note: the iovec is not modified during the copy + */ +int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, + int offset, size_t count) +{ + int len = iov_length(from, count) - offset; + int copy = skb_headlen(skb); + int size, offset1 = 0; + int i = 0; + + /* Skip over from offset */ + while (count && (offset >= from->iov_len)) { + offset -= from->iov_len; + ++from; + --count; + } + + /* copy up to skb headlen */ + while (count && (copy > 0)) { + size = min_t(unsigned int, copy, from->iov_len - offset); + if (copy_from_user(skb->data + offset1, from->iov_base + offset, + size)) + return -EFAULT; + if (copy > size) { + ++from; + --count; + offset = 0; + } else + offset += size; + copy -= size; + offset1 += size; + } + + if (len == offset1) + return 0; + + while (count--) { + struct page *page[MAX_SKB_FRAGS]; + int num_pages; + unsigned long base; + unsigned long truesize; + + len = from->iov_len - offset; + if (!len) { + offset = 0; + ++from; + continue; + } + base = (unsigned long)from->iov_base + offset; + size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; + if (i + size > MAX_SKB_FRAGS) + return -EMSGSIZE; + num_pages = get_user_pages_fast(base, size, 0, &page[i]); + if (num_pages != size) { + int j; + + for (j = 0; j < num_pages; j++) + put_page(page[i + j]); + return -EFAULT; + } + truesize = size * PAGE_SIZE; + skb->data_len += len; + skb->len += len; + skb->truesize += truesize; + atomic_add(truesize, &skb->sk->sk_wmem_alloc); + while (len) { + int off = base & ~PAGE_MASK; + int size = min_t(int, len, PAGE_SIZE - off); + __skb_fill_page_desc(skb, i, page[i], off, size); + skb_shinfo(skb)->nr_frags++; + /* increase sk_wmem_alloc */ + base += size; + len -= size; + i++; + } + offset = 0; + ++from; + } + return 0; +} +EXPORT_SYMBOL(zerocopy_sg_from_iovec); + static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, u8 __user *to, int len, __wsum *csump)