Re: [PATCH 2.6] ibmveth bug fixes 4/4

[Santiago Leon <santil@us.ibm.com>]

[-- Attachment #1: Type: text/plain, Size: 289 bytes --]

Andrew...

I had discussion over email with Dave Hansen about this patch and after 
I explained the bug and the fix, he recommended that I include a comment 
in the patch.  So here's an updated patch. Please apply.

-- 
Santiago A. Leon
Power Linux Development
IBM Linux Technology Center

[-- Attachment #2: ibmveth_rmb.patch --]
[-- Type: text/plain, Size: 941 bytes --]

===== drivers/net/ibmveth.c 1.14 vs edited =====
--- 1.14/drivers/net/ibmveth.c	Tue Aug 10 19:09:45 2004
+++ edited/drivers/net/ibmveth.c	Tue Aug 10 19:30:10 2004
@@ -271,7 +271,6 @@
 	adapter->rx_no_buffer = *(u64*)(((char*)adapter->buffer_list_addr) + 4096 - 8);
 
 	atomic_inc(&adapter->not_replenishing);
-	ibmveth_assert(atomic_read(&adapter->not_replenishing) == 1);
 }
 
 /* kick the replenish tasklet if we need replenishing and it isn't already running */
@@ -733,6 +732,14 @@
 
 		if(ibmveth_rxq_pending_buffer(adapter)) {
 			struct sk_buff *skb;
+
+			/* This barrier is necessary because we might be 
+			   reading a control dword and then reading an old 
+			   cached correlator dword. Also, the hypervisor
+			   guarantees that the control field will be globally
+			   visible after all the other fields are visible, 
+			*/
+			rmb();
 
 			if(!ibmveth_rxq_buffer_valid(adapter)) {
 				wmb(); /* suggested by larson1 */