From 77561557447d3be586e701815e261c93c11ded00 Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Sun, 17 Apr 2011 13:06:23 -0400 Subject: [PATCH] tipc: Fix issues with fragmentation of an existing message buffer Modifies the routine that fragments an existing message buffer to use similar logic to that used when generating fragments from an iovec. The routine now creates a complete chain of fragments and adds them to the link transmit queue as a unit, so that the link sends all fragments or none; this prevents the incomplete transmission of a fragmented message that might otherwise result because of link congestion or memory exhaustion. This change also ensures that the counter recording the number of fragmented messages sent by the link is now incremented only if the message is actually sent. Signed-off-by: Allan Stephens Signed-off-by: Paul Gortmaker --- net/tipc/link.c | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-) diff --git a/net/tipc/link.c b/net/tipc/link.c index ad356df12d1e..02b083e5c219 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -2406,6 +2406,8 @@ void tipc_link_recv_bundle(struct sk_buff *buf) */ static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf) { + struct sk_buff *buf_chain = NULL; + struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain; struct tipc_msg *inmsg = buf_msg(buf); struct tipc_msg fragm_hdr; u32 insize = msg_size(inmsg); @@ -2414,7 +2416,7 @@ static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf) u32 rest = insize; u32 pack_sz = l_ptr->max_pkt; u32 fragm_sz = pack_sz - INT_H_SIZE; - u32 fragm_no = 1; + u32 fragm_no = 0; u32 destaddr; if (msg_short(inmsg)) @@ -2426,9 +2428,6 @@ static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf) tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT, INT_H_SIZE, destaddr); - msg_set_long_msgno(&fragm_hdr, l_ptr->long_msg_seq_no++); - msg_set_fragm_no(&fragm_hdr, fragm_no); - l_ptr->stats.sent_fragmented++; /* Chop up message: */ @@ -2441,27 +2440,37 @@ static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf) } fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE); if (fragm == NULL) { - warn("Link unable to fragment message\n"); - dsz = -ENOMEM; - goto exit; + buf_discard(buf); + while (buf_chain) { + buf = buf_chain; + buf_chain = buf_chain->next; + buf_discard(buf); + } + return -ENOMEM; } msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE); + fragm_no++; + msg_set_fragm_no(&fragm_hdr, fragm_no); skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE); skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs, fragm_sz); - /* Send queued messages first, if any: */ + buf_chain_tail->next = fragm; + buf_chain_tail = fragm; - l_ptr->stats.sent_fragments++; - tipc_link_send_buf(l_ptr, fragm); - if (!tipc_link_is_up(l_ptr)) - return dsz; - msg_set_fragm_no(&fragm_hdr, ++fragm_no); rest -= fragm_sz; crs += fragm_sz; msg_set_type(&fragm_hdr, FRAGMENT); } -exit: buf_discard(buf); + + /* Append chain of fragments to send queue & send them */ + + l_ptr->long_msg_seq_no++; + link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no); + l_ptr->stats.sent_fragments += fragm_no; + l_ptr->stats.sent_fragmented++; + tipc_link_push_queue(l_ptr); + return dsz; } -- 2.20.1