[PATCH] fix buffer starvation race in ibmveth

[PATCH] fix buffer starvation race in ibmveth

[Santiago Leon]

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Andrew,

There's a chance that the receive buffers are being consumed at the same 
rate as they are being replenished in ibmveth_replenish_task()... 
Meanwhile, the calls to schedule_replenishing() from ibmveth_poll() 
won't schedule another replenishing cycle (because the not_replenishing 
flag is zero), starving the buffers and making the adapter unable to 
receive packets unless the module is reloaded... Here's a small patch 
that will fix it by scheduling another replenishing task after toggling 
the not_replenishing flag.

Please apply.

Signed-Off-By: Santiago Leon <santil@us.ibm.com>
-- 
Santiago A. Leon
Power Linux Development
IBM Linux Technology Center

[-- Attachment #2: ibmveth_buff_starve.patch --]
[-- Type: text/plain, Size: 1207 bytes --]

===== drivers/net/ibmveth.c 1.19 vs edited =====
--- 1.19/drivers/net/ibmveth.c	2004-11-22 00:42:54 -06:00
+++ edited/drivers/net/ibmveth.c	2004-12-03 15:27:40 -06:00
@@ -96,6 +96,7 @@
 static void ibmveth_proc_register_adapter(struct ibmveth_adapter *adapter);
 static void ibmveth_proc_unregister_adapter(struct ibmveth_adapter *adapter);
 static irqreturn_t ibmveth_interrupt(int irq, void *dev_instance, struct pt_regs *regs);
+static inline void ibmveth_schedule_replenishing(struct ibmveth_adapter*);
 
 #ifdef CONFIG_PROC_FS
 #define IBMVETH_PROC_DIR "ibmveth"
@@ -104,7 +105,7 @@
 
 static const char ibmveth_driver_name[] = "ibmveth";
 static const char ibmveth_driver_string[] = "IBM i/pSeries Virtual Ethernet Driver";
-#define ibmveth_driver_version "1.02"
+#define ibmveth_driver_version "1.03"
 
 MODULE_AUTHOR("Santiago Leon <santil@us.ibm.com>");
 MODULE_DESCRIPTION("IBM i/pSeries Virtual Ethernet Driver");
@@ -271,6 +272,8 @@
 	adapter->rx_no_buffer = *(u64*)(((char*)adapter->buffer_list_addr) + 4096 - 8);
 
 	atomic_inc(&adapter->not_replenishing);
+
+	ibmveth_schedule_replenishing(adapter);
 }
 
 /* kick the replenish tasklet if we need replenishing and it isn't already running */