[PATCH 11/12] iseries_veth: Add a per-connection ack timer
Michael Ellerman
michael at ellerman.id.au
Thu Jun 30 20:20:40 EST 2005
Currently the iseries_veth driver contravenes the specification in
Documentation/networking/driver.txt, in that if packets are not acked by
the other LPAR they will sit around forever.
This patch adds a per-connection timer which fires if we've had no acks for
five seconds. This is superior to the generic TX timer because it catches
the case of a small number of packets being sent and never acked.
---
drivers/net/iseries_veth.c | 75 +++++++++++++++++++++++++++++++++++++++++----
1 files changed, 69 insertions(+), 6 deletions(-)
Index: veth-dev/drivers/net/iseries_veth.c
===================================================================
--- veth-dev.orig/drivers/net/iseries_veth.c
+++ veth-dev/drivers/net/iseries_veth.c
@@ -132,6 +132,11 @@ struct veth_lpar_connection {
struct kref refcount;
struct timer_list ack_timer;
+ struct timer_list reset_timer;
+ unsigned int reset_timeout;
+ unsigned long last_contact;
+ int outstanding_tx;
+
spinlock_t lock;
unsigned long state;
HvLpInstanceId src_inst;
@@ -171,7 +176,8 @@ static int veth_start_xmit(struct sk_buf
static void veth_recycle_msg(struct veth_lpar_connection *, struct veth_msg *);
static void veth_flush_pending(struct veth_lpar_connection *cnx);
static void veth_receive(struct veth_lpar_connection *, struct VethLpEvent *);
-static void veth_timed_ack(unsigned long connectionPtr);
+static void veth_timed_ack(unsigned long ptr);
+static void veth_timed_reset(unsigned long ptr);
/*
* Utility functions
@@ -353,7 +359,7 @@ static void veth_handle_int(struct VethL
HvLpIndex rlp = event->base_event.xSourceLp;
struct veth_lpar_connection *cnx = veth_cnx[rlp];
unsigned long flags;
- int i;
+ int i, acked = 0;
BUG_ON(! cnx);
@@ -367,13 +373,22 @@ static void veth_handle_int(struct VethL
break;
case VethEventTypeFramesAck:
spin_lock_irqsave(&cnx->lock, flags);
+
for (i = 0; i < VETH_MAX_ACKS_PER_MSG; ++i) {
u16 msgnum = event->u.frames_ack_data.token[i];
- if (msgnum < VETH_NUMBUFFERS)
+ if (msgnum < VETH_NUMBUFFERS) {
veth_recycle_msg(cnx, cnx->msgs + msgnum);
+ cnx->outstanding_tx--;
+ acked++;
+ }
}
+
+ if (acked > 0)
+ cnx->last_contact = jiffies;
+
spin_unlock_irqrestore(&cnx->lock, flags);
+
veth_flush_pending(cnx);
break;
case VethEventTypeFrames:
@@ -447,8 +462,6 @@ static void veth_statemachine(void *p)
restart:
if (cnx->state & VETH_STATE_RESET) {
- int i;
-
if (cnx->state & VETH_STATE_OPEN)
HvCallEvent_closeLpEventPath(cnx->remote_lp,
HvLpEvent_Type_VirtualLan);
@@ -467,15 +480,20 @@ static void veth_statemachine(void *p)
| VETH_STATE_SENTCAPACK | VETH_STATE_READY);
/* Clean up any leftover messages */
- if (cnx->msgs)
+ if (cnx->msgs) {
+ int i;
for (i = 0; i < VETH_NUMBUFFERS; ++i)
veth_recycle_msg(cnx, cnx->msgs + i);
+ }
+ cnx->outstanding_tx = 0;
/* Drop the lock so we can do stuff that might sleep or
* take other locks. */
spin_unlock_irq(&cnx->lock);
del_timer_sync(&cnx->ack_timer);
+ del_timer_sync(&cnx->reset_timer);
+
veth_flush_pending(cnx);
spin_lock_irq(&cnx->lock);
@@ -628,9 +646,16 @@ static int veth_init_connection(u8 rlp)
cnx->remote_lp = rlp;
spin_lock_init(&cnx->lock);
INIT_WORK(&cnx->statemachine_wq, veth_statemachine, cnx);
+
init_timer(&cnx->ack_timer);
cnx->ack_timer.function = veth_timed_ack;
cnx->ack_timer.data = (unsigned long) cnx;
+
+ init_timer(&cnx->reset_timer);
+ cnx->reset_timer.function = veth_timed_reset;
+ cnx->reset_timer.data = (unsigned long) cnx;
+ cnx->reset_timeout = 5 * HZ * (VETH_ACKTIMEOUT / 1000000);
+
memset(&cnx->pending_acks, 0xff, sizeof (cnx->pending_acks));
veth_cnx[rlp] = cnx;
@@ -937,6 +962,13 @@ static int veth_transmit_to_one(struct s
if (rc != HvLpEvent_Rc_Good)
goto recycle_and_drop;
+ /* If the timer's not already running, start it now. */
+ if (0 == cnx->outstanding_tx)
+ mod_timer(&cnx->reset_timer, jiffies + cnx->reset_timeout);
+
+ cnx->last_contact = jiffies;
+ cnx->outstanding_tx++;
+
spin_unlock_irqrestore(&cnx->lock, flags);
return 0;
@@ -1081,6 +1113,37 @@ static void veth_flush_pending(struct ve
}
}
+static void veth_timed_reset(unsigned long ptr)
+{
+ struct veth_lpar_connection *cnx = (struct veth_lpar_connection *)ptr;
+ unsigned long trigger_time, flags;
+
+ /* FIXME is it possible this fires after veth_stop_connection()?
+ * That would reschedule the statemachine for 5 seconds and probably
+ * execute it after the module's been unloaded. Hmm. */
+
+ spin_lock_irqsave(&cnx->lock, flags);
+
+ if (cnx->outstanding_tx > 0) {
+ trigger_time = cnx->last_contact + cnx->reset_timeout;
+
+ if (trigger_time < jiffies) {
+ cnx->state |= VETH_STATE_RESET;
+ veth_kick_statemachine(cnx);
+ veth_error("%d packets not acked by LPAR %d within %d "
+ "seconds, resetting.\n",
+ cnx->outstanding_tx, cnx->remote_lp,
+ cnx->reset_timeout / HZ);
+ } else {
+ /* Reschedule the timer */
+ trigger_time = jiffies + cnx->reset_timeout;
+ mod_timer(&cnx->reset_timer, trigger_time);
+ }
+ }
+
+ spin_unlock_irqrestore(&cnx->lock, flags);
+}
+
/*
* Rx path
*/
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