Re: [patch 2.6.12-rc1-mm4] fork_connector: add a fork connector

From: Jay Lan
Date: Fri Apr 08 2005 - 22:33:42 EST


With the patch you provide to me, i did not see the bugcheck
at cn_queue_wrapper() at the console.

Unmatched sequence number messages still happened. We expect
to lose packets under system stressed situation, but i still
observed duplicate messages, which concerned me.

Unmatched seq. Rcvd=79477, expected=79478 <=== duplicate
Unmatched seq. Rcvd=713823, expected=713422 * loss of 401 msgs
Unmatched seq. Rcvd=80024, expected=79901 * loss of 123 msgs

Unmatched seq. Rcvd=93632, expected=93633 <=== duplicate
Unmatched seq. Rcvd=94718, expected=93970
Unmatched seq. Rcvd=743576, expected=743502

Unmatched seq. Rcvd=123506, expected=123507 <=== duplicate
Unmatched seq. Rcvd=773753, expected=773503
Unmatched seq. Rcvd=124111, expected=123938

Unmatched seq. Rcvd=157172, expected=157173 <=== duplicate
Unmatched seq. Rcvd=813024, expected=812913 <=== duplicate
Unmatched seq. Rcvd=813024, expected=813025 <=== duplicate

Unmatched seq. Rcvd=157830, expected=157501
Unmatched seq. Rcvd=158408, expected=158145
Unmatched seq. Rcvd=813678, expected=813438

The test system was a two cpu ia64.

Thanks,
- jay


Evgeniy Polyakov wrote:
On Fri, 08 Apr 2005 15:08:13 -0700
Jay Lan <jlan@xxxxxxxxxxxx> wrote:


Hi Evgeniy,

Forget about my previous request of a new patch.

The failures were straight forward enough to figure out.


Ok.
The latest sources are always awailable at
http://tservice.net.ru/~s0mbre/archive/connector


- jay

Jay Lan wrote:

My workarea was based on 2.6.12-rc1-mm4 plus Guilluame's patch.

Your patch caused 5 out of 8 hunks failure at connector.c
and one failure at connector.h.

Could you generate a new patch based on my version? A tar
file of complete source of drivers/connector would work
also. :)

Thanks!
- jay

Evgeniy Polyakov wrote:


Could you give attached patch a try instead of previous one.
It adds gfp mask into cn_netlink_send() call also.
If you need updated CBUS sources, feel free to ask, I will send updated sources with Andrew's comments resolved too.

I do not know exactly your connector version, so patch will probably be applied with fuzz.

feel free to contact if it does not apply, I will send
the whole sources.

Thank you.

* looking for johnpol@xxxxxxxxxxxxxxxx/connector--main--0--patch-38 to compare with
* comparing to johnpol@xxxxxxxxxxxxxxxx/connector--main--0--patch-38
M connector.c
M connector.h
M cbus.c

* modified files

--- orig/drivers/connector/connector.c
+++ mod/drivers/connector/connector.c
@@ -70,7 +70,7 @@
* then it is new message.
*
*/
-void cn_netlink_send(struct cn_msg *msg, u32 __groups)
+void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask)
{
struct cn_callback_entry *n, *__cbq;
unsigned int size;
@@ -102,7 +102,7 @@

size = NLMSG_SPACE(sizeof(*msg) + msg->len);

- skb = alloc_skb(size, GFP_ATOMIC);
+ skb = alloc_skb(size, gfp_mask);
if (!skb) {
printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", size);
return;
@@ -119,11 +119,11 @@
#endif
NETLINK_CB(skb).dst_groups = groups;
-
- uskb = skb_clone(skb, GFP_ATOMIC);
- if (uskb)
+#if 0
+ uskb = skb_clone(skb, gfp_mask);
+ if (uskb && 0)
netlink_unicast(dev->nls, uskb, 0, 0);
- +#endif netlink_broadcast(dev->nls, skb, 0, groups, GFP_ATOMIC);

return;
@@ -158,7 +158,7 @@
}
spin_unlock_bh(&dev->cbdev->queue_lock);

- return found;
+ return (found)?0:-ENODEV;
}

/*
@@ -181,7 +181,6 @@
"requested msg->len=%u[%u], nlh->nlmsg_len=%u, skb->len=%u.\n",
msg->len, NLMSG_SPACE(msg->len + sizeof(*msg)),
nlh->nlmsg_len, skb->len);
- kfree_skb(skb);
return -EINVAL;
}
#if 0
@@ -215,17 +214,18 @@
skb->len, skb->data_len, skb->truesize, skb->protocol,
skb_cloned(skb), skb_shared(skb));
#endif
- while (skb->len >= NLMSG_SPACE(0)) {
+ if (skb->len >= NLMSG_SPACE(0)) {
nlh = (struct nlmsghdr *)skb->data;
+
if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
skb->len < nlh->nlmsg_len ||
nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
-#if 0
+#if 1
printk(KERN_INFO "nlmsg_len=%u, sizeof(*nlh)=%u\n",
nlh->nlmsg_len, sizeof(*nlh));
#endif
kfree_skb(skb);
- break;
+ goto out;
}

len = NLMSG_ALIGN(nlh->nlmsg_len);
@@ -233,22 +233,11 @@
len = skb->len;

err = __cn_rx_skb(skb, nlh);
- if (err) {
-#if 0
- if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
- netlink_ack(skb, nlh, -err);
-#endif
- break;
- } else {
-#if 0
- if (nlh->nlmsg_flags & NLM_F_ACK)
- netlink_ack(skb, nlh, 0);
-#endif
- break;
- }
- skb_pull(skb, len);
+ if (err < 0)
+ kfree_skb(skb);
}
- +
+out:
kfree_skb(__skb);
}

@@ -310,7 +299,7 @@
m.ack = notify_event;

memcpy(&m.id, id, sizeof(m.id));
- cn_netlink_send(&m, ctl->group);
+ cn_netlink_send(&m, ctl->group, GFP_ATOMIC);
}
}
spin_unlock_bh(&notify_lock);


--- orig/include/linux/connector.h
+++ mod/include/linux/connector.h
@@ -148,7 +148,7 @@

int cn_add_callback(struct cb_id *, char *, void (* callback)(void *));
void cn_del_callback(struct cb_id *);
-void cn_netlink_send(struct cn_msg *, u32);
+void cn_netlink_send(struct cn_msg *, u32, int);

int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb);
void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);








Evgeniy Polyakov

Only failure makes us experts. -- Theo de Raadt

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