sctp: allow sctp_transmit_packet and others to use gfp

Currently sctp_sendmsg() triggers some calls that will allocate memory
with GFP_ATOMIC even when not necessary. In the case of
sctp_packet_transmit it will allocate a linear skb that will be used to
construct the packet and this may cause sends to fail due to ENOMEM more
often than anticipated specially with big MTUs.

This patch thus allows it to inherit gfp flags from upper calls so that
it can use GFP_KERNEL if it was triggered by a sctp_sendmsg call or
similar. All others, like retransmits or flushes started from BH, are
still allocated using GFP_ATOMIC.

In netperf tests this didn't result in any performance drawbacks when
memory is not too fragmented and made it trigger ENOMEM way less often.

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 47 insertions, 33 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 5d6a03fad378..8449ca26aa0b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -62,11 +62,13 @@
 #include <net/sctp/sm.h>
 
 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
-					    __u8 type, __u8 flags, int paylen);
+					    __u8 type, __u8 flags, int paylen,
+					    gfp_t gfp);
 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
-					 __u8 flags, int paylen);
+					 __u8 flags, int paylen, gfp_t gfp);
 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
-					   __u8 type, __u8 flags, int paylen);
+					   __u8 type, __u8 flags, int paylen,
+					   gfp_t gfp);
 static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 					const struct sctp_association *asoc,
 					const struct sctp_chunk *init_chunk,
@@ -318,7 +320,7 @@ struct sctp_chunk *sctp_make_init(const struct sctp_association *asoc,
 	 * PLEASE DO NOT FIXME [This version does not support Host Name.]
 	 */
 
-	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize);
+	retval = sctp_make_control(asoc, SCTP_CID_INIT, 0, chunksize, gfp);
 	if (!retval)
 		goto nodata;
 
@@ -465,7 +467,7 @@ struct sctp_chunk *sctp_make_init_ack(const struct sctp_association *asoc,
 					num_ext);
 
 	/* Now allocate and fill out the chunk.  */
-	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize);
+	retval = sctp_make_control(asoc, SCTP_CID_INIT_ACK, 0, chunksize, gfp);
 	if (!retval)
 		goto nomem_chunk;
 
@@ -570,7 +572,8 @@ struct sctp_chunk *sctp_make_cookie_echo(const struct sctp_association *asoc,
 	cookie_len = asoc->peer.cookie_len;
 
 	/* Build a cookie echo chunk.  */
-	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0, cookie_len);
+	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ECHO, 0,
+				   cookie_len, GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 	retval->subh.cookie_hdr =
@@ -615,7 +618,7 @@ struct sctp_chunk *sctp_make_cookie_ack(const struct sctp_association *asoc,
 {
 	struct sctp_chunk *retval;
 
-	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0);
+	retval = sctp_make_control(asoc, SCTP_CID_COOKIE_ACK, 0, 0, GFP_ATOMIC);
 
 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
 	 *
@@ -664,7 +667,7 @@ struct sctp_chunk *sctp_make_cwr(const struct sctp_association *asoc,
 
 	cwr.lowest_tsn = htonl(lowest_tsn);
 	retval = sctp_make_control(asoc, SCTP_CID_ECN_CWR, 0,
-				   sizeof(sctp_cwrhdr_t));
+				   sizeof(sctp_cwrhdr_t), GFP_ATOMIC);
 
 	if (!retval)
 		goto nodata;
@@ -698,7 +701,7 @@ struct sctp_chunk *sctp_make_ecne(const struct sctp_association *asoc,
 
 	ecne.lowest_tsn = htonl(lowest_tsn);
 	retval = sctp_make_control(asoc, SCTP_CID_ECN_ECNE, 0,
-				   sizeof(sctp_ecnehdr_t));
+				   sizeof(sctp_ecnehdr_t), GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 	retval->subh.ecne_hdr =
@@ -713,7 +716,8 @@ nodata:
  */
 struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
 				       const struct sctp_sndrcvinfo *sinfo,
-				       int data_len, __u8 flags, __u16 ssn)
+				       int data_len, __u8 flags, __u16 ssn,
+				       gfp_t gfp)
 {
 	struct sctp_chunk *retval;
 	struct sctp_datahdr dp;
@@ -734,7 +738,7 @@ struct sctp_chunk *sctp_make_datafrag_empty(struct sctp_association *asoc,
 		dp.ssn = htons(ssn);
 
 	chunk_len = sizeof(dp) + data_len;
-	retval = sctp_make_data(asoc, flags, chunk_len);
+	retval = sctp_make_data(asoc, flags, chunk_len, gfp);
 	if (!retval)
 		goto nodata;
 
@@ -781,7 +785,7 @@ struct sctp_chunk *sctp_make_sack(const struct sctp_association *asoc)
 		+ sizeof(__u32) * num_dup_tsns;
 
 	/* Create the chunk.  */
-	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len);
+	retval = sctp_make_control(asoc, SCTP_CID_SACK, 0, len, GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 
@@ -861,7 +865,7 @@ struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
 	shut.cum_tsn_ack = htonl(ctsn);
 
 	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,
-				   sizeof(sctp_shutdownhdr_t));
+				   sizeof(sctp_shutdownhdr_t), GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 
@@ -879,7 +883,8 @@ struct sctp_chunk *sctp_make_shutdown_ack(const struct sctp_association *asoc,
 {
 	struct sctp_chunk *retval;
 
-	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0);
+	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_ACK, 0, 0,
+				   GFP_ATOMIC);
 
 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
 	 *
@@ -908,7 +913,8 @@ struct sctp_chunk *sctp_make_shutdown_complete(
 	 */
 	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;
 
-	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
+	retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags,
+				   0, GFP_ATOMIC);
 
 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
 	 *
@@ -947,7 +953,8 @@ struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,
 			flags = SCTP_CHUNK_FLAG_T;
 	}
 
-	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint);
+	retval = sctp_make_control(asoc, SCTP_CID_ABORT, flags, hint,
+				   GFP_ATOMIC);
 
 	/* RFC 2960 6.4 Multi-homed SCTP Endpoints
 	 *
@@ -1139,7 +1146,8 @@ struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
 	struct sctp_chunk *retval;
 	sctp_sender_hb_info_t hbinfo;
 
-	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0, sizeof(hbinfo));
+	retval = sctp_make_control(asoc, SCTP_CID_HEARTBEAT, 0,
+				   sizeof(hbinfo), GFP_ATOMIC);
 
 	if (!retval)
 		goto nodata;
@@ -1167,7 +1175,8 @@ struct sctp_chunk *sctp_make_heartbeat_ack(const struct sctp_association *asoc,
 {
 	struct sctp_chunk *retval;
 
-	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen);
+	retval  = sctp_make_control(asoc, SCTP_CID_HEARTBEAT_ACK, 0, paylen,
+				    GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 
@@ -1200,7 +1209,7 @@ static struct sctp_chunk *sctp_make_op_error_space(
 	struct sctp_chunk *retval;
 
 	retval = sctp_make_control(asoc, SCTP_CID_ERROR, 0,
-				   sizeof(sctp_errhdr_t) + size);
+				   sizeof(sctp_errhdr_t) + size, GFP_ATOMIC);
 	if (!retval)
 		goto nodata;
 
@@ -1271,7 +1280,8 @@ struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
 		return NULL;
 
 	retval = sctp_make_control(asoc, SCTP_CID_AUTH, 0,
-			hmac_desc->hmac_len + sizeof(sctp_authhdr_t));
+			hmac_desc->hmac_len + sizeof(sctp_authhdr_t),
+			GFP_ATOMIC);
 	if (!retval)
 		return NULL;
 
@@ -1309,11 +1319,11 @@ struct sctp_chunk *sctp_make_auth(const struct sctp_association *asoc)
  */
 struct sctp_chunk *sctp_chunkify(struct sk_buff *skb,
 			    const struct sctp_association *asoc,
-			    struct sock *sk)
+			    struct sock *sk, gfp_t gfp)
 {
 	struct sctp_chunk *retval;
 
-	retval = kmem_cache_zalloc(sctp_chunk_cachep, GFP_ATOMIC);
+	retval = kmem_cache_zalloc(sctp_chunk_cachep, gfp);
 
 	if (!retval)
 		goto nodata;
@@ -1361,7 +1371,8 @@ const union sctp_addr *sctp_source(const struct sctp_chunk *chunk)
  * arguments, reserving enough space for a 'paylen' byte payload.
  */
 static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
-					    __u8 type, __u8 flags, int paylen)
+					    __u8 type, __u8 flags, int paylen,
+					    gfp_t gfp)
 {
 	struct sctp_chunk *retval;
 	sctp_chunkhdr_t *chunk_hdr;
@@ -1369,8 +1380,7 @@ static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
 	struct sock *sk;
 
 	/* No need to allocate LL here, as this is only a chunk. */
-	skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen),
-			GFP_ATOMIC);
+	skb = alloc_skb(WORD_ROUND(sizeof(sctp_chunkhdr_t) + paylen), gfp);
 	if (!skb)
 		goto nodata;
 
@@ -1381,7 +1391,7 @@ static struct sctp_chunk *_sctp_make_chunk(const struct sctp_association *asoc,
 	chunk_hdr->length = htons(sizeof(sctp_chunkhdr_t));
 
 	sk = asoc ? asoc->base.sk : NULL;
-	retval = sctp_chunkify(skb, asoc, sk);
+	retval = sctp_chunkify(skb, asoc, sk, gfp);
 	if (!retval) {
 		kfree_skb(skb);
 		goto nodata;
@@ -1400,16 +1410,18 @@ nodata:
 }
 
 static struct sctp_chunk *sctp_make_data(const struct sctp_association *asoc,
-					 __u8 flags, int paylen)
+					 __u8 flags, int paylen, gfp_t gfp)
 {
-	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen);
+	return _sctp_make_chunk(asoc, SCTP_CID_DATA, flags, paylen, gfp);
 }
 
 static struct sctp_chunk *sctp_make_control(const struct sctp_association *asoc,
-					    __u8 type, __u8 flags, int paylen)
+					    __u8 type, __u8 flags, int paylen,
+					    gfp_t gfp)
 {
-	struct sctp_chunk *chunk = _sctp_make_chunk(asoc, type, flags, paylen);
+	struct sctp_chunk *chunk;
 
+	chunk = _sctp_make_chunk(asoc, type, flags, paylen, gfp);
 	if (chunk)
 		sctp_control_set_owner_w(chunk);
 
@@ -2756,7 +2768,8 @@ static struct sctp_chunk *sctp_make_asconf(struct sctp_association *asoc,
 	length += addrlen;
 
 	/* Create the chunk.  */
-	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length);
+	retval = sctp_make_control(asoc, SCTP_CID_ASCONF, 0, length,
+				   GFP_ATOMIC);
 	if (!retval)
 		return NULL;
 
@@ -2940,7 +2953,8 @@ static struct sctp_chunk *sctp_make_asconf_ack(const struct sctp_association *as
 	int			length = sizeof(asconf) + vparam_len;
 
 	/* Create the chunk.  */
-	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length);
+	retval = sctp_make_control(asoc, SCTP_CID_ASCONF_ACK, 0, length,
+				   GFP_ATOMIC);
 	if (!retval)
 		return NULL;
 
@@ -3500,7 +3514,7 @@ struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc,
 
 	hint = (nstreams + 1) * sizeof(__u32);
 
-	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint);
+	retval = sctp_make_control(asoc, SCTP_CID_FWD_TSN, 0, hint, GFP_ATOMIC);
 
 	if (!retval)
 		return NULL;