diff options
Diffstat (limited to 'net/core/sock.c')
-rw-r--r-- | net/core/sock.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index 27f218bba43f..f68dff0d7bc4 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2239,6 +2239,62 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag) } EXPORT_SYMBOL(sk_page_frag_refill); +int sk_alloc_sg(struct sock *sk, int len, struct scatterlist *sg, + int *sg_num_elem, unsigned int *sg_size, + int first_coalesce) +{ + struct page_frag *pfrag; + unsigned int size = *sg_size; + int num_elem = *sg_num_elem, use = 0, rc = 0; + struct scatterlist *sge; + unsigned int orig_offset; + + len -= size; + pfrag = sk_page_frag(sk); + + while (len > 0) { + if (!sk_page_frag_refill(sk, pfrag)) { + rc = -ENOMEM; + goto out; + } + + use = min_t(int, len, pfrag->size - pfrag->offset); + + if (!sk_wmem_schedule(sk, use)) { + rc = -ENOMEM; + goto out; + } + + sk_mem_charge(sk, use); + size += use; + orig_offset = pfrag->offset; + pfrag->offset += use; + + sge = sg + num_elem - 1; + if (num_elem > first_coalesce && sg_page(sg) == pfrag->page && + sg->offset + sg->length == orig_offset) { + sg->length += use; + } else { + sge++; + sg_unmark_end(sge); + sg_set_page(sge, pfrag->page, use, orig_offset); + get_page(pfrag->page); + ++num_elem; + if (num_elem == MAX_SKB_FRAGS) { + rc = -ENOSPC; + break; + } + } + + len -= use; + } +out: + *sg_size = size; + *sg_num_elem = num_elem; + return rc; +} +EXPORT_SYMBOL(sk_alloc_sg); + static void __lock_sock(struct sock *sk) __releases(&sk->sk_lock.slock) __acquires(&sk->sk_lock.slock) |