Date: Sat, 5 May 2007 17:25:51 +0200 (CEST) From: Stefan Richter Subject: [PATCH 2/2] ieee1394: eth1394: handle tlabel exhaustion When eth1394 was unable to acquire a transaction label, it just dropped outgoing packets without attempt to resend them later. The transmit queue is now halted if no tlabel is available to ->hard_start_xmit(). A workqueue job is then scheduled to catch the moment when ieee1394 recycled the next lot of tlabels. Fixes http://bugzilla.kernel.org/show_bug.cgi?id=8402 Signed-off-by: Stefan Richter --- drivers/ieee1394/eth1394.c | 80 +++++++++++++++++++++++++++++-------- drivers/ieee1394/eth1394.h | 4 + 2 files changed, 67 insertions(+), 17 deletions(-) Index: linux/drivers/ieee1394/eth1394.c =================================================================== --- linux.orig/drivers/ieee1394/eth1394.c 2007-05-05 15:46:14.000000000 +0200 +++ linux/drivers/ieee1394/eth1394.c 2007-05-05 16:48:48.000000000 +0200 @@ -47,6 +47,7 @@ #include #include #include +#include #include #include @@ -235,6 +236,9 @@ static int ether1394_open(struct net_dev /* This is called after an "ifdown" */ static int ether1394_stop(struct net_device *dev) { + /* flush priv->wake */ + flush_scheduled_work(); + netif_stop_queue(dev); return 0; } @@ -531,6 +535,37 @@ static void ether1394_init_dev(struct ne } /* + * Wake the queue up after commonly encountered transmit failure conditions are + * hopefully over. Currently only tlabel exhaustion is accounted for. + */ +static void ether1394_wake_queue(struct work_struct *work) +{ + struct eth1394_priv *priv; + struct hpsb_packet *packet; + + priv = container_of(work, struct eth1394_priv, wake); + packet = hpsb_alloc_packet(0); + + /* This is really bad, but unjam the queue anyway. */ + if (!packet) + goto out; + + packet->host = priv->host; + packet->node_id = priv->wake_node; + /* + * A transaction label is all we really want. If we get one, it almost + * always means we can get a lot more because the ieee1394 core recycled + * a whole batch of tlabels, at last. + */ + if (hpsb_get_tlabel(packet) == 0) + hpsb_free_tlabel(packet); + + hpsb_free_packet(packet); +out: + netif_wake_queue(priv->wake_dev); +} + +/* * This function is called every time a card is found. It is generally called * when the module is installed. This is where we add all of our ethernet * devices. One for each host. @@ -574,6 +609,8 @@ static void ether1394_add_host(struct hp spin_lock_init(&priv->lock); priv->host = host; priv->local_fifo = fifo_addr; + INIT_WORK(&priv->wake, ether1394_wake_queue); + priv->wake_dev = dev; hi = hpsb_create_hostinfo(ð1394_highlevel, host, sizeof(*hi)); if (hi == NULL) { @@ -1390,22 +1427,17 @@ static int ether1394_prep_write_packet(s u64 addr, void *data, int tx_len) { p->node_id = node; - p->data = NULL; - p->tcode = TCODE_WRITEB; - p->header[1] = host->node_id << 16 | addr >> 32; - p->header[2] = addr & 0xffffffff; + if (hpsb_get_tlabel(p)) + return -EAGAIN; + p->tcode = TCODE_WRITEB; p->header_size = 16; p->expect_response = 1; - - if (hpsb_get_tlabel(p)) { - ETH1394_PRINT_G(KERN_ERR, "Out of tlabels\n"); - return -1; - } p->header[0] = p->node_id << 16 | p->tlabel << 10 | 1 << 8 | TCODE_WRITEB << 4; - + p->header[1] = host->node_id << 16 | addr >> 32; + p->header[2] = addr & 0xffffffff; p->header[3] = tx_len << 16; p->data_size = (tx_len + 3) & ~3; p->data = data; @@ -1451,7 +1483,7 @@ static int ether1394_send_packet(struct packet = ether1394_alloc_common_packet(priv->host); if (!packet) - return -1; + return -ENOMEM; if (ptask->tx_type == ETH1394_GASP) { int length = tx_len + 2 * sizeof(quadlet_t); @@ -1462,7 +1494,7 @@ static int ether1394_send_packet(struct ptask->addr, ptask->skb->data, tx_len)) { hpsb_free_packet(packet); - return -1; + return -EAGAIN; } ptask->packet = packet; @@ -1471,7 +1503,7 @@ static int ether1394_send_packet(struct if (hpsb_send_packet(packet) < 0) { ether1394_free_packet(packet); - return -1; + return -EIO; } return 0; @@ -1514,13 +1546,18 @@ static void ether1394_complete_cb(void * ptask->outstanding_pkts--; if (ptask->outstanding_pkts > 0 && !fail) { - int tx_len; + int tx_len, err; /* Add the encapsulation header to the fragment */ tx_len = ether1394_encapsulate(ptask->skb, ptask->max_payload, &ptask->hdr); - if (ether1394_send_packet(ptask, tx_len)) + err = ether1394_send_packet(ptask, tx_len); + if (err) { + if (err == -EAGAIN) + ETH1394_PRINT_G(KERN_ERR, "Out of tlabels\n"); + ether1394_dg_complete(ptask, 1); + } } else { ether1394_dg_complete(ptask, fail); } @@ -1633,8 +1670,17 @@ static int ether1394_tx(struct sk_buff * /* Add the encapsulation header to the fragment */ tx_len = ether1394_encapsulate(skb, max_payload, &ptask->hdr); dev->trans_start = jiffies; - if (ether1394_send_packet(ptask, tx_len)) - goto fail; + if (ether1394_send_packet(ptask, tx_len)) { + if (dest_node == (LOCAL_BUS | ALL_NODES)) + goto fail; + + /* Most failures of ether1394_send_packet are recoverable. */ + netif_stop_queue(dev); + priv->wake_node = dest_node; + schedule_work(&priv->wake); + kmem_cache_free(packet_task_cache, ptask); + return NETDEV_TX_BUSY; + } return NETDEV_TX_OK; fail: Index: linux/drivers/ieee1394/eth1394.h =================================================================== --- linux.orig/drivers/ieee1394/eth1394.h 2007-05-05 15:46:14.000000000 +0200 +++ linux/drivers/ieee1394/eth1394.h 2007-05-05 15:51:15.000000000 +0200 @@ -66,6 +66,10 @@ struct eth1394_priv { int bc_dgl; /* Outgoing broadcast datagram label */ struct list_head ip_node_list; /* List of IP capable nodes */ struct unit_directory *ud_list[ALL_NODES]; /* Cached unit dir list */ + + struct work_struct wake; /* Wake up after xmit failure */ + struct net_device *wake_dev; /* Stupid backlink for .wake */ + nodeid_t wake_node; /* Destination of failed xmit */ };