From: Jon Paul Maloy Date: Fri, 13 Mar 2015 20:08:08 +0000 (-0400) Subject: tipc: extract bundled buffers by cloning instead of copying X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c1336ee472f83a90ede01fdae095ed5d0a2934c9;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git tipc: extract bundled buffers by cloning instead of copying When we currently extract a bundled buffer from a message bundle in the function tipc_msg_extract(), we allocate a new buffer and explicitly copy the linear data area. This is unnecessary, since we can just clone the buffer and do skb_pull() on the clone to move the data pointer to the correct position. This is what we do in this commit. Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- diff --git a/net/tipc/link.c b/net/tipc/link.c index 8c6639d107fc..56c39b1a53a9 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1,7 +1,7 @@ /* * net/tipc/link.c: TIPC link code * - * Copyright (c) 1996-2007, 2012-2014, Ericsson AB + * Copyright (c) 1996-2007, 2012-2015, Ericsson AB * Copyright (c) 2004-2007, 2010-2013, Wind River Systems * All rights reserved. * @@ -1117,7 +1117,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr) ackd = msg_ack(msg); /* Release acked messages */ - if (n_ptr->bclink.recv_permitted) + if (likely(n_ptr->bclink.recv_permitted)) tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg)); released = 0; @@ -1712,45 +1712,24 @@ void tipc_link_dup_queue_xmit(struct tipc_link *l_ptr, } } -/** - * buf_extract - extracts embedded TIPC message from another message - * @skb: encapsulating message buffer - * @from_pos: offset to extract from - * - * Returns a new message buffer containing an embedded message. The - * encapsulating buffer is left unchanged. - */ -static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos) -{ - struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos); - u32 size = msg_size(msg); - struct sk_buff *eb; - - eb = tipc_buf_acquire(size); - if (eb) - skb_copy_to_linear_data(eb, msg, size); - return eb; -} - /* tipc_link_dup_rcv(): Receive a tunnelled DUPLICATE_MSG packet. * Owner node is locked. */ -static void tipc_link_dup_rcv(struct tipc_link *l_ptr, - struct sk_buff *t_buf) +static void tipc_link_dup_rcv(struct tipc_link *link, + struct sk_buff *skb) { - struct sk_buff *buf; + struct sk_buff *iskb; + int pos = 0; - if (!tipc_link_is_up(l_ptr)) + if (!tipc_link_is_up(link)) return; - buf = buf_extract(t_buf, INT_H_SIZE); - if (buf == NULL) { + if (!tipc_msg_extract(skb, &iskb, &pos)) { pr_warn("%sfailed to extract inner dup pkt\n", link_co_err); return; } - - /* Add buffer to deferred queue, if applicable: */ - link_handle_out_of_seq_msg(l_ptr, buf); + /* Append buffer to deferred queue, if applicable: */ + link_handle_out_of_seq_msg(link, iskb); } /* tipc_link_failover_rcv(): Receive a tunnelled ORIGINAL_MSG packet @@ -1762,6 +1741,7 @@ static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr, struct tipc_msg *t_msg = buf_msg(t_buf); struct sk_buff *buf = NULL; struct tipc_msg *msg; + int pos = 0; if (tipc_link_is_up(l_ptr)) tipc_link_reset(l_ptr); @@ -1773,8 +1753,7 @@ static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr, /* Should there be an inner packet? */ if (l_ptr->exp_msg_count) { l_ptr->exp_msg_count--; - buf = buf_extract(t_buf, INT_H_SIZE); - if (buf == NULL) { + if (!tipc_msg_extract(t_buf, &buf, &pos)) { pr_warn("%sno inner failover pkt\n", link_co_err); goto exit; } diff --git a/net/tipc/msg.c b/net/tipc/msg.c index ff8c64cd1cd9..333d2ae1cf76 100644 --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -372,38 +372,40 @@ bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu) /** * tipc_msg_extract(): extract bundled inner packet from buffer - * @skb: linear outer buffer, to be extracted from. + * @skb: buffer to be extracted from. * @iskb: extracted inner buffer, to be returned - * @pos: position of msg to be extracted. Returns with pointer of next msg + * @pos: position in outer message of msg to be extracted. + * Returns position of next msg * Consumes outer buffer when last packet extracted * Returns true when when there is an extracted buffer, otherwise false */ bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos) { struct tipc_msg *msg; - int imsz; - struct tipc_msg *imsg; + int imsz, offset; + *iskb = NULL; if (unlikely(skb_linearize(skb))) - return false; + goto none; + msg = buf_msg(skb); - imsg = (struct tipc_msg *)(msg_data(msg) + *pos); - /* Is there space left for shortest possible message? */ - if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE)) + offset = msg_hdr_sz(msg) + *pos; + if (unlikely(offset > (msg_size(msg) - MIN_H_SIZE))) goto none; - imsz = msg_size(imsg); - /* Is there space left for current message ? */ - if ((*pos + imsz) > msg_data_sz(msg)) + *iskb = skb_clone(skb, GFP_ATOMIC); + if (unlikely(!*iskb)) goto none; - *iskb = tipc_buf_acquire(imsz); - if (!*iskb) + skb_pull(*iskb, offset); + imsz = msg_size(buf_msg(*iskb)); + skb_trim(*iskb, imsz); + if (unlikely(!tipc_msg_validate(*iskb))) goto none; - skb_copy_to_linear_data(*iskb, imsg, imsz); *pos += align(imsz); return true; none: kfree_skb(skb); + kfree_skb(*iskb); *iskb = NULL; return false; }