drbd: Preallocate one page per drbd_socket as a receive buffer

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -554,6 +554,8 @@ struct p_delay_probe93 {
 #error "PAGE_SIZE too small"
 #endif
 
+#define DRBD_SOCKET_BUFFER_SIZE 4096
+
 union p_polymorph {
         struct p_header           header;
         struct p_handshake       handshake;
@@ -803,7 +805,7 @@ struct drbd_socket {
 	/* this way we get our
 	 * send/receive buffers off the stack */
 	union p_polymorph sbuf;
-	union p_polymorph rbuf;
+	void *rbuf;
 };
 
 struct drbd_md {

drivers/block/drbd/drbd_main.c

@@ -2272,6 +2272,19 @@ struct drbd_tconn *conn_by_name(const char *name)
 	return tconn;
 }
 
+static int drbd_alloc_socket(struct drbd_socket *socket)
+{
+	socket->rbuf = (void *) __get_free_page(GFP_KERNEL);
+	if (!socket->rbuf)
+		return -ENOMEM;
+	return 0;
+}
+
+static void drbd_free_socket(struct drbd_socket *socket)
+{
+	free_page((unsigned long) socket->rbuf);
+}
+
 struct drbd_tconn *drbd_new_tconn(const char *name)
 {
 	struct drbd_tconn *tconn;
@@ -2284,6 +2297,11 @@ struct drbd_tconn *drbd_new_tconn(const char *name)
 	if (!tconn->name)
 		goto fail;
 
+	if (drbd_alloc_socket(&tconn->data))
+		goto fail;
+	if (drbd_alloc_socket(&tconn->meta))
+		goto fail;
+
 	if (!zalloc_cpumask_var(&tconn->cpu_mask, GFP_KERNEL))
 		goto fail;
 
@@ -2322,6 +2340,8 @@ struct drbd_tconn *drbd_new_tconn(const char *name)
 fail:
 	tl_cleanup(tconn);
 	free_cpumask_var(tconn->cpu_mask);
+	drbd_free_socket(&tconn->meta);
+	drbd_free_socket(&tconn->data);
 	kfree(tconn->name);
 	kfree(tconn);
 
@@ -2334,6 +2354,8 @@ void drbd_free_tconn(struct drbd_tconn *tconn)
 	idr_destroy(&tconn->volumes);
 
 	free_cpumask_var(tconn->cpu_mask);
+	drbd_free_socket(&tconn->meta);
+	drbd_free_socket(&tconn->data);
 	kfree(tconn->name);
 	kfree(tconn->int_dig_out);
 	kfree(tconn->int_dig_in);

drivers/block/drbd/drbd_receiver.c

@@ -743,7 +743,7 @@ static int drbd_send_fp(struct drbd_tconn *tconn, struct socket *sock, enum drbd
 
 static enum drbd_packet drbd_recv_fp(struct drbd_tconn *tconn, struct socket *sock)
 {
-	struct p_header80 *h = &tconn->data.rbuf.header.h80;
+	struct p_header80 *h = tconn->data.rbuf;
 	int rr;
 
 	rr = drbd_recv_short(sock, h, sizeof(*h), 0);
@@ -994,7 +994,7 @@ static int decode_header(struct drbd_tconn *tconn, struct p_header *h, struct pa
 
 static int drbd_recv_header(struct drbd_tconn *tconn, struct packet_info *pi)
 {
-	struct p_header *h = &tconn->data.rbuf.header;
+	struct p_header *h = tconn->data.rbuf;
 	int err;
 
 	err = drbd_recv_all_warn(tconn, h, sizeof(*h));
@@ -1236,7 +1236,7 @@ static int receive_Barrier(struct drbd_conf *mdev, enum drbd_packet cmd,
 			   unsigned int data_size)
 {
 	int rv;
-	struct p_barrier *p = &mdev->tconn->data.rbuf.barrier;
+	struct p_barrier *p = mdev->tconn->data.rbuf;
 	struct drbd_epoch *epoch;
 
 	inc_unacked(mdev);
@@ -1546,7 +1546,7 @@ static int receive_DataReply(struct drbd_conf *mdev, enum drbd_packet cmd,
 	struct drbd_request *req;
 	sector_t sector;
 	int err;
-	struct p_data *p = &mdev->tconn->data.rbuf.data;
+	struct p_data *p = mdev->tconn->data.rbuf;
 
 	sector = be64_to_cpu(p->sector);
 
@@ -1574,7 +1574,7 @@ static int receive_RSDataReply(struct drbd_conf *mdev, enum drbd_packet cmd,
 {
 	sector_t sector;
 	int err;
-	struct p_data *p = &mdev->tconn->data.rbuf.data;
+	struct p_data *p = mdev->tconn->data.rbuf;
 
 	sector = be64_to_cpu(p->sector);
 	D_ASSERT(p->block_id == ID_SYNCER);
@@ -1963,7 +1963,7 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packet cmd,
 {
 	sector_t sector;
 	struct drbd_peer_request *peer_req;
-	struct p_data *p = &mdev->tconn->data.rbuf.data;
+	struct p_data *p = mdev->tconn->data.rbuf;
 	u32 peer_seq = be32_to_cpu(p->seq_num);
 	int rw = WRITE;
 	u32 dp_flags;
@@ -2147,7 +2147,7 @@ static int receive_DataRequest(struct drbd_conf *mdev, enum drbd_packet cmd,
 	struct digest_info *di = NULL;
 	int size, verb;
 	unsigned int fault_type;
-	struct p_block_req *p =	&mdev->tconn->data.rbuf.block_req;
+	struct p_block_req *p =	mdev->tconn->data.rbuf;
 
 	sector = be64_to_cpu(p->sector);
 	size   = be32_to_cpu(p->blksize);
@@ -2867,7 +2867,7 @@ static int cmp_after_sb(enum drbd_after_sb_p peer, enum drbd_after_sb_p self)
 static int receive_protocol(struct drbd_tconn *tconn, enum drbd_packet cmd,
 			    unsigned int data_size)
 {
-	struct p_protocol *p = &tconn->data.rbuf.protocol;
+	struct p_protocol *p = tconn->data.rbuf;
 	int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
 	int p_want_lose, p_two_primaries, cf;
 	char p_integrity_alg[SHARED_SECRET_MAX] = "";
@@ -2969,7 +2969,7 @@ struct crypto_hash *drbd_crypto_alloc_digest_safe(const struct drbd_conf *mdev,
 static int receive_SyncParam(struct drbd_conf *mdev, enum drbd_packet cmd,
 			     unsigned int packet_size)
 {
-	struct p_rs_param_95 *p = &mdev->tconn->data.rbuf.rs_param_95;
+	struct p_rs_param_95 *p = mdev->tconn->data.rbuf;
 	unsigned int header_size, data_size, exp_max_sz;
 	struct crypto_hash *verify_tfm = NULL;
 	struct crypto_hash *csums_tfm = NULL;
@@ -3141,7 +3141,7 @@ static void warn_if_differ_considerably(struct drbd_conf *mdev,
 static int receive_sizes(struct drbd_conf *mdev, enum drbd_packet cmd,
 			 unsigned int data_size)
 {
-	struct p_sizes *p = &mdev->tconn->data.rbuf.sizes;
+	struct p_sizes *p = mdev->tconn->data.rbuf;
 	enum determine_dev_size dd = unchanged;
 	sector_t p_size, p_usize, my_usize;
 	int ldsc = 0; /* local disk size changed */
@@ -3239,7 +3239,7 @@ static int receive_sizes(struct drbd_conf *mdev, enum drbd_packet cmd,
 static int receive_uuids(struct drbd_conf *mdev, enum drbd_packet cmd,
 			 unsigned int data_size)
 {
-	struct p_uuids *p = &mdev->tconn->data.rbuf.uuids;
+	struct p_uuids *p = mdev->tconn->data.rbuf;
 	u64 *p_uuid;
 	int i, updated_uuids = 0;
 
@@ -3335,7 +3335,7 @@ static union drbd_state convert_state(union drbd_state ps)
 static int receive_req_state(struct drbd_conf *mdev, enum drbd_packet cmd,
 			     unsigned int data_size)
 {
-	struct p_req_state *p = &mdev->tconn->data.rbuf.req_state;
+	struct p_req_state *p = mdev->tconn->data.rbuf;
 	union drbd_state mask, val;
 	enum drbd_state_rv rv;
 
@@ -3362,7 +3362,7 @@ static int receive_req_state(struct drbd_conf *mdev, enum drbd_packet cmd,
 static int receive_req_conn_state(struct drbd_tconn *tconn, enum drbd_packet cmd,
 				  unsigned int data_size)
 {
-	struct p_req_state *p = &tconn->data.rbuf.req_state;
+	struct p_req_state *p = tconn->data.rbuf;
 	union drbd_state mask, val;
 	enum drbd_state_rv rv;
 
@@ -3387,7 +3387,7 @@ static int receive_req_conn_state(struct drbd_tconn *tconn, enum drbd_packet cmd
 static int receive_state(struct drbd_conf *mdev, enum drbd_packet cmd,
 			 unsigned int data_size)
 {
-	struct p_state *p = &mdev->tconn->data.rbuf.state;
+	struct p_state *p = mdev->tconn->data.rbuf;
 	union drbd_state os, ns, peer_state;
 	enum drbd_disk_state real_peer_disk;
 	enum chg_state_flags cs_flags;
@@ -3540,7 +3540,7 @@ static int receive_state(struct drbd_conf *mdev, enum drbd_packet cmd,
 static int receive_sync_uuid(struct drbd_conf *mdev, enum drbd_packet cmd,
 			     unsigned int data_size)
 {
-	struct p_rs_uuid *p = &mdev->tconn->data.rbuf.rs_uuid;
+	struct p_rs_uuid *p = mdev->tconn->data.rbuf;
 
 	wait_event(mdev->misc_wait,
 		   mdev->state.conn == C_WF_SYNC_UUID ||
@@ -3752,7 +3752,7 @@ static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packet cmd,
 	struct bm_xfer_ctx c;
 	void *buffer;
 	int err;
-	struct p_header *h = &mdev->tconn->data.rbuf.header;
+	struct p_header *h = mdev->tconn->data.rbuf;
 	struct packet_info pi;
 
 	drbd_bm_lock(mdev, "receive bitmap", BM_LOCKED_SET_ALLOWED);
@@ -3893,7 +3893,7 @@ static int receive_UnplugRemote(struct drbd_conf *mdev, enum drbd_packet cmd,
 static int receive_out_of_sync(struct drbd_conf *mdev, enum drbd_packet cmd,
 			       unsigned int data_size)
 {
-	struct p_block_desc *p = &mdev->tconn->data.rbuf.block_desc;
+	struct p_block_desc *p = mdev->tconn->data.rbuf;
 
 	switch (mdev->state.conn) {
 	case C_WF_SYNC_UUID:
@@ -3948,16 +3948,9 @@ static struct data_cmd drbd_cmd_handler[] = {
 	[P_CONN_ST_CHG_REQ] = { 0, sizeof(struct p_req_state), CONN, { .conn_fn = receive_req_conn_state } },
 };
 
-/* All handler functions that expect a sub-header get that sub-heder in
-   mdev->tconn->data.rbuf.header.head.payload.
-
-   Usually in mdev->tconn->data.rbuf.header.head the callback can find the usual
-   p_header, but they may not rely on that. Since there is also p_header95 !
- */
-
 static void drbdd(struct drbd_tconn *tconn)
 {
-	struct p_header *header = &tconn->data.rbuf.header;
+	struct p_header *header = tconn->data.rbuf;
 	struct packet_info pi;
 	size_t shs; /* sub header size */
 	int err;
@@ -4188,7 +4181,7 @@ static int drbd_send_handshake(struct drbd_tconn *tconn)
 static int drbd_do_handshake(struct drbd_tconn *tconn)
 {
 	/* ASSERT current == tconn->receiver ... */
-	struct p_handshake *p = &tconn->data.rbuf.handshake;
+	struct p_handshake *p = tconn->data.rbuf;
 	const int expect = sizeof(struct p_handshake) - sizeof(struct p_header80);
 	struct packet_info pi;
 	int err;
@@ -4435,7 +4428,7 @@ int drbdd_init(struct drbd_thread *thi)
 
 static int got_conn_RqSReply(struct drbd_tconn *tconn, enum drbd_packet cmd)
 {
-	struct p_req_state_reply *p = &tconn->meta.rbuf.req_state_reply;
+	struct p_req_state_reply *p = tconn->meta.rbuf;
 	int retcode = be32_to_cpu(p->retcode);
 
 	if (retcode >= SS_SUCCESS) {
@@ -4452,7 +4445,7 @@ static int got_conn_RqSReply(struct drbd_tconn *tconn, enum drbd_packet cmd)
 
 static int got_RqSReply(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_req_state_reply *p = &mdev->tconn->meta.rbuf.req_state_reply;
+	struct p_req_state_reply *p = mdev->tconn->meta.rbuf;
 	int retcode = be32_to_cpu(p->retcode);
 
 	if (retcode >= SS_SUCCESS) {
@@ -4485,7 +4478,7 @@ static int got_PingAck(struct drbd_tconn *tconn, enum drbd_packet cmd)
 
 static int got_IsInSync(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 	sector_t sector = be64_to_cpu(p->sector);
 	int blksize = be32_to_cpu(p->blksize);
 
@@ -4530,7 +4523,7 @@ validate_req_change_req_state(struct drbd_conf *mdev, u64 id, sector_t sector,
 
 static int got_BlockAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 	sector_t sector = be64_to_cpu(p->sector);
 	int blksize = be32_to_cpu(p->blksize);
 	enum drbd_req_event what;
@@ -4575,7 +4568,7 @@ static int got_BlockAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 
 static int got_NegAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 	sector_t sector = be64_to_cpu(p->sector);
 	int size = be32_to_cpu(p->blksize);
 	bool missing_ok = mdev->tconn->net_conf->wire_protocol == DRBD_PROT_A ||
@@ -4608,7 +4601,7 @@ static int got_NegAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 
 static int got_NegDReply(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 	sector_t sector = be64_to_cpu(p->sector);
 
 	update_peer_seq(mdev, be32_to_cpu(p->seq_num));
@@ -4625,7 +4618,7 @@ static int got_NegRSDReply(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
 	sector_t sector;
 	int size;
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 
 	sector = be64_to_cpu(p->sector);
 	size = be32_to_cpu(p->blksize);
@@ -4654,7 +4647,7 @@ static int got_NegRSDReply(struct drbd_conf *mdev, enum drbd_packet cmd)
 
 static int got_BarrierAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_barrier_ack *p = &mdev->tconn->meta.rbuf.barrier_ack;
+	struct p_barrier_ack *p = mdev->tconn->meta.rbuf;
 
 	tl_release(mdev->tconn, p->barrier, be32_to_cpu(p->set_size));
 
@@ -4670,7 +4663,7 @@ static int got_BarrierAck(struct drbd_conf *mdev, enum drbd_packet cmd)
 
 static int got_OVResult(struct drbd_conf *mdev, enum drbd_packet cmd)
 {
-	struct p_block_ack *p = &mdev->tconn->meta.rbuf.block_ack;
+	struct p_block_ack *p = mdev->tconn->meta.rbuf;
 	struct drbd_work *w;
 	sector_t sector;
 	int size;
@@ -4776,7 +4769,7 @@ static struct asender_cmd asender_tbl[] = {
 int drbd_asender(struct drbd_thread *thi)
 {
 	struct drbd_tconn *tconn = thi->tconn;
-	struct p_header *h = &tconn->meta.rbuf.header;
+	struct p_header *h = tconn->meta.rbuf;
 	struct asender_cmd *cmd = NULL;
 	struct packet_info pi;
 	int rv;