2.4.13

 arch

 i386

 kernel

diff -u --recursive --new-file v2.4.12/linux/arch/i386/kernel/smp.c linux/arch/i386/kernel/smp.c
--- v2.4.12/linux/arch/i386/kernel/smp.c   Tue Oct  9 17:06:51 2001
+++ linux/arch/i386/kernel/smp.c   Tue Oct 23 14:17:10 2001
@@ -507,10 +507,9 @@
    atomic_t started;
    atomic_t finished;
    int wait;
-} __attribute__ ((__aligned__(SMP_CACHE_BYTES)));
+};
 
 static struct call_data_struct * call_data;
-static struct call_data_struct call_data_array[NR_CPUS];
 
 /*
  * this function sends a 'generic call function' IPI to all other CPUs
@@ -532,45 +531,33 @@
  * hardware interrupt handler, you may call it from a bottom half handler.
  */
 {
-   struct call_data_struct *data;
-   int cpus = (cpu_online_map & ~(1 << smp_processor_id()));
+   struct call_data_struct data;
+   int cpus = smp_num_cpus-1;
 
    if (!cpus)
       return 0;
 
-   data = &call_data_array[smp_processor_id()];
-   
-   data->func = func;
-   data->info = info;
-   data->wait = wait;
+   data.func = func;
+   data.info = info;
+   atomic_set(&data.started, 0);
+   data.wait = wait;
    if (wait)
-      atomic_set(&data->finished, 0);
-   /* We have do to this one last to make sure that the IPI service
-    * code desn't get confused if it gets an unexpected repeat
-    * trigger of an old IPI while we're still setting up the new
-    * one. */
-   atomic_set(&data->started, 0);
-
-   local_bh_disable();
-   spin_lock(&call_lock);
-   call_data = data;
+      atomic_set(&data.finished, 0);
+
+   spin_lock_bh(&call_lock);
+   call_data = &data;
+   wmb();
    /* Send a message to all other CPUs and wait for them to respond */
    send_IPI_allbutself(CALL_FUNCTION_VECTOR);
 
    /* Wait for response */
-   while (atomic_read(&data->started) != cpus)
+   while (atomic_read(&data.started) != cpus)
       barrier();
 
-   /* It is now safe to reuse the "call_data" global, but we need
-    * to keep local bottom-halves disabled until after waiters have
-    * been acknowledged to prevent reuse of the per-cpu call data
-    * entry. */
-   spin_unlock(&call_lock);
-
    if (wait)
-      while (atomic_read(&data->finished) != cpus)
+      while (atomic_read(&data.finished) != cpus)
          barrier();
-   local_bh_enable();
+   spin_unlock_bh(&call_lock);
 
    return 0;
 }
@@ -620,17 +607,18 @@
 
    ack_APIC_irq();
    /*
-    * Notify initiating CPU that I've grabbed the data and am about
-    * to execute the function (and avoid servicing any single IPI
-    * twice)
+    * Notify initiating CPU that I've grabbed the data and am
+    * about to execute the function
     */
-   if (test_and_set_bit(smp_processor_id(), &call_data->started))
-      return;
+   mb();
+   atomic_inc(&call_data->started);
    /*
     * At this point the info structure may be out of scope unless wait==1
     */
    (*func)(info);
-   if (wait)
-      set_bit(smp_processor_id(), &call_data->finished);
+   if (wait) {
+      mb();
+      atomic_inc(&call_data->finished);
+   }
 }