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Date: Tue, 03 Jul 2012 10:39:36 -0400
From: Vlad Yasevich <vyasevich@...il.com>
To: Neil Horman <nhorman@...driver.com>
CC: netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
linux-sctp@...r.kernel.org
Subject: Re: [PATCH] sctp: refactor sctp_packet_append_chunk and clenup some
memory leaks
On 07/02/2012 03:59 PM, Neil Horman wrote:
> While doing some recent work on sctp sack bundling I noted that
> sctp_packet_append_chunk was pretty inefficient. Specifially, it was called
> recursively while trying to bundle auth and sack chunks. Because of that we
> call sctp_packet_bundle_sack and sctp_packet_bundle_auth a total of 4 times for
> every call to sctp_packet_append_chunk, knowing that at least 3 of those calls
> will do nothing.
>
> So lets refactor sctp_packet_bundle_auth to have an outer part that does the
> attempted bundling, and an inner part that just does the chunk appends. This
> saves us several calls per iteration that we just don't need.
>
> Also, noticed that the auth and sack bundling fail to free the chunks they
> allocate if the append fails, so make sure we add that in
>
> Signed-off-by: Neil Horman<nhorman@...driver.com>
> CC: Vlad Yasevich<vyasevich@...il.com>
Acked-by: Vlad Yasevich <vyasevich@...il.com>
-vlad
> CC: "David S. Miller"<davem@...emloft.net>
> CC: linux-sctp@...r.kernel.org
> ---
> net/sctp/output.c | 80 +++++++++++++++++++++++++++++++++++------------------
> 1 files changed, 53 insertions(+), 27 deletions(-)
>
> diff --git a/net/sctp/output.c b/net/sctp/output.c
> index 0de6cd5..0b62f6c 100644
> --- a/net/sctp/output.c
> +++ b/net/sctp/output.c
> @@ -64,6 +64,8 @@
> #include<net/sctp/checksum.h>
>
> /* Forward declarations for private helpers. */
> +static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
> + struct sctp_chunk *chunk);
> static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
> struct sctp_chunk *chunk);
> static void sctp_packet_append_data(struct sctp_packet *packet,
> @@ -224,7 +226,10 @@ static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt,
> if (!auth)
> return retval;
>
> - retval = sctp_packet_append_chunk(pkt, auth);
> + retval = __sctp_packet_append_chunk(pkt, auth);
> +
> + if (retval != SCTP_XMIT_OK)
> + sctp_chunk_free(auth);
>
> return retval;
> }
> @@ -256,48 +261,31 @@ static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt,
> asoc->a_rwnd = asoc->rwnd;
> sack = sctp_make_sack(asoc);
> if (sack) {
> - retval = sctp_packet_append_chunk(pkt, sack);
> + retval = __sctp_packet_append_chunk(pkt, sack);
> + if (retval != SCTP_XMIT_OK) {
> + sctp_chunk_free(sack);
> + goto out;
> + }
> asoc->peer.sack_needed = 0;
> if (del_timer(timer))
> sctp_association_put(asoc);
> }
> }
> }
> +out:
> return retval;
> }
>
> +
> /* Append a chunk to the offered packet reporting back any inability to do
> * so.
> */
> -sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet,
> - struct sctp_chunk *chunk)
> +static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
> + struct sctp_chunk *chunk)
> {
> sctp_xmit_t retval = SCTP_XMIT_OK;
> __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length));
>
> - SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet,
> - chunk);
> -
> - /* Data chunks are special. Before seeing what else we can
> - * bundle into this packet, check to see if we are allowed to
> - * send this DATA.
> - */
> - if (sctp_chunk_is_data(chunk)) {
> - retval = sctp_packet_can_append_data(packet, chunk);
> - if (retval != SCTP_XMIT_OK)
> - goto finish;
> - }
> -
> - /* Try to bundle AUTH chunk */
> - retval = sctp_packet_bundle_auth(packet, chunk);
> - if (retval != SCTP_XMIT_OK)
> - goto finish;
> -
> - /* Try to bundle SACK chunk */
> - retval = sctp_packet_bundle_sack(packet, chunk);
> - if (retval != SCTP_XMIT_OK)
> - goto finish;
> -
> /* Check to see if this chunk will fit into the packet */
> retval = sctp_packet_will_fit(packet, chunk, chunk_len);
> if (retval != SCTP_XMIT_OK)
> @@ -339,6 +327,44 @@ finish:
> return retval;
> }
>
> +/* Append a chunk to the offered packet reporting back any inability to do
> + * so.
> + */
> +sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet,
> + struct sctp_chunk *chunk)
> +{
> + sctp_xmit_t retval = SCTP_XMIT_OK;
> + __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length));
> +
> + SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet,
> + chunk);
> +
> + /* Data chunks are special. Before seeing what else we can
> + * bundle into this packet, check to see if we are allowed to
> + * send this DATA.
> + */
> + if (sctp_chunk_is_data(chunk)) {
> + retval = sctp_packet_can_append_data(packet, chunk);
> + if (retval != SCTP_XMIT_OK)
> + goto finish;
> + }
> +
> + /* Try to bundle AUTH chunk */
> + retval = sctp_packet_bundle_auth(packet, chunk);
> + if (retval != SCTP_XMIT_OK)
> + goto finish;
> +
> + /* Try to bundle SACK chunk */
> + retval = sctp_packet_bundle_sack(packet, chunk);
> + if (retval != SCTP_XMIT_OK)
> + goto finish;
> +
> + retval = __sctp_packet_append_chunk(packet, chunk);
> +
> +finish:
> + return retval;
> +}
> +
> /* All packets are sent to the network through this function from
> * sctp_outq_tail().
> *
--
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