alpha: convert to generic helpers for IPI function calls

This converts alpha to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single().

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

3 files changed, 14 insertions, 163 deletions

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 729cdbdf8036..dbe8c280fea9 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -528,6 +528,7 @@ config ARCH_MAY_HAVE_PC_FDC
 config SMP
         bool "Symmetric multi-processing support"
         depends on ALPHA_SABLE || ALPHA_LYNX || ALPHA_RAWHIDE || ALPHA_DP264 || ALPHA_WILDFIRE || ALPHA_TITAN || ALPHA_GENERIC || ALPHA_SHARK || ALPHA_MARVEL
+        select USE_GENERIC_SMP_HELPERS
         ---help---
           This enables support for systems with more than one CPU. If you have
           a system with only one CPU, like most personal computers, say N. If
diff --git a/arch/alpha/kernel/core_marvel.c b/arch/alpha/kernel/core_marvel.c
index b04f1feb1dda..ced4aae8b804 100644
--- a/arch/alpha/kernel/core_marvel.c
+++ b/arch/alpha/kernel/core_marvel.c
@@ -660,9 +660,9 @@ __marvel_rtc_io(u8 b, unsigned long addr, int write)
 
 #ifdef CONFIG_SMP
                 if (smp_processor_id() != boot_cpuid)
-                        smp_call_function_on_cpu(__marvel_access_rtc,
-                                                 &rtc_access, 1, 1,
-                                                 cpumask_of_cpu(boot_cpuid));
+                        smp_call_function_single(boot_cpuid,
+                                                 __marvel_access_rtc,
+                                                 &rtc_access, 1, 1);
                 else
                         __marvel_access_rtc(&rtc_access);
 #else
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 2525692db0ab..95c905be9154 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -62,6 +62,7 @@ static struct {
 enum ipi_message_type {
         IPI_RESCHEDULE,
         IPI_CALL_FUNC,
+        IPI_CALL_FUNC_SINGLE,
         IPI_CPU_STOP,
 };
 
@@ -558,51 +559,6 @@ send_ipi_message(cpumask_t to_whom, enum ipi_message_type operation)
                 wripir(i);
 }
 
-/* Structure and data for smp_call_function.  This is designed to 
-   minimize static memory requirements.  Plus it looks cleaner.  */
-
-struct smp_call_struct {
-        void (*func) (void *info);
-        void *info;
-        long wait;
-        atomic_t unstarted_count;
-        atomic_t unfinished_count;
-};
-
-static struct smp_call_struct *smp_call_function_data;
-
-/* Atomicly drop data into a shared pointer.  The pointer is free if
-   it is initially locked.  If retry, spin until free.  */
-
-static int
-pointer_lock (void *lock, void *data, int retry)
-{
-        void *old, *tmp;
-
-        mb();
- again:
-        /* Compare and swap with zero.  */
-        asm volatile (
-        "1:     ldq_l   %0,%1\n"
-        "       mov     %3,%2\n"
-        "       bne     %0,2f\n"
-        "       stq_c   %2,%1\n"
-        "       beq     %2,1b\n"
-        "2:"
-        : "=&r"(old), "=m"(*(void **)lock), "=&r"(tmp)
-        : "r"(data)
-        : "memory");
-
-        if (old == 0)
-                return 0;
-        if (! retry)
-                return -EBUSY;
-
-        while (*(void **)lock)
-                barrier();
-        goto again;
-}
-
 void
 handle_ipi(struct pt_regs *regs)
 {
@@ -632,31 +588,12 @@ handle_ipi(struct pt_regs *regs)
                         break;
 
                 case IPI_CALL_FUNC:
-                    {
-                        struct smp_call_struct *data;
-                        void (*func)(void *info);
-                        void *info;
-                        int wait;
-
-                        data = smp_call_function_data;
-                        func = data->func;
-                        info = data->info;
-                        wait = data->wait;
-
-                        /* Notify the sending CPU that the data has been
-                           received, and execution is about to begin.  */
-                        mb();
-                        atomic_dec (&data->unstarted_count);
-
-                        /* At this point the structure may be gone unless
-                           wait is true.  */
-                        (*func)(info);
-
-                        /* Notify the sending CPU that the task is done.  */
-                        mb();
-                        if (wait) atomic_dec (&data->unfinished_count);
+                        generic_smp_call_function_interrupt();
+                        break;
+
+                case IPI_CALL_FUNC_SINGLE:
+                        generic_smp_call_function_single_interrupt();
                         break;
-                    }
 
                 case IPI_CPU_STOP:
                         halt();
@@ -700,102 +637,15 @@ smp_send_stop(void)
         send_ipi_message(to_whom, IPI_CPU_STOP);
 }
 
-/*
- * Run a function on all other CPUs.
- *  <func>      The function to run. This must be fast and non-blocking.
- *  <info>      An arbitrary pointer to pass to the function.
- *  <retry>     If true, keep retrying until ready.
- *  <wait>      If true, wait until function has completed on other CPUs.
- *  [RETURNS]   0 on success, else a negative status code.
- *
- * Does not return until remote CPUs are nearly ready to execute <func>
- * or are or have executed.
- * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler or from a bottom half handler.
- */
-
-int
-smp_call_function_on_cpu (void (*func) (void *info), void *info, int retry,
-                          int wait, cpumask_t to_whom)
+void arch_send_call_function_ipi(cpumask_t mask)
 {
-        struct smp_call_struct data;
-        unsigned long timeout;
-        int num_cpus_to_call;
-        
-        /* Can deadlock when called with interrupts disabled */
-        WARN_ON(irqs_disabled());
-
-        data.func = func;
-        data.info = info;
-        data.wait = wait;
-
-        cpu_clear(smp_processor_id(), to_whom);
-        num_cpus_to_call = cpus_weight(to_whom);
-
-        atomic_set(&data.unstarted_count, num_cpus_to_call);
-        atomic_set(&data.unfinished_count, num_cpus_to_call);
-
-        /* Acquire the smp_call_function_data mutex.  */
-        if (pointer_lock(&smp_call_function_data, &data, retry))
-                return -EBUSY;
-
-        /* Send a message to the requested CPUs.  */
-        send_ipi_message(to_whom, IPI_CALL_FUNC);
-
-        /* Wait for a minimal response.  */
-        timeout = jiffies + HZ;
-        while (atomic_read (&data.unstarted_count) > 0
-               && time_before (jiffies, timeout))
-                barrier();
-
-        /* If there's no response yet, log a message but allow a longer
-         * timeout period -- if we get a response this time, log
-         * a message saying when we got it.. 
-         */
-        if (atomic_read(&data.unstarted_count) > 0) {
-                long start_time = jiffies;
-                printk(KERN_ERR "%s: initial timeout -- trying long wait\n",
-                       __func__);
-                timeout = jiffies + 30 * HZ;
-                while (atomic_read(&data.unstarted_count) > 0
-                       && time_before(jiffies, timeout))
-                        barrier();
-                if (atomic_read(&data.unstarted_count) <= 0) {
-                        long delta = jiffies - start_time;
-                        printk(KERN_ERR 
-                               "%s: response %ld.%ld seconds into long wait\n",
-                               __func__, delta / HZ,
-                               (100 * (delta - ((delta / HZ) * HZ))) / HZ);
-                }
-        }
-
-        /* We either got one or timed out -- clear the lock. */
-        mb();
-        smp_call_function_data = NULL;
-
-        /* 
-         * If after both the initial and long timeout periods we still don't
-         * have a response, something is very wrong...
-         */
-        BUG_ON(atomic_read (&data.unstarted_count) > 0);
-
-        /* Wait for a complete response, if needed.  */
-        if (wait) {
-                while (atomic_read (&data.unfinished_count) > 0)
-                        barrier();
-        }
-
-        return 0;
+        send_ipi_message(mask, IPI_CALL_FUNC);
 }
-EXPORT_SYMBOL(smp_call_function_on_cpu);
 
-int
-smp_call_function (void (*func) (void *info), void *info, int retry, int wait)
+void arch_send_call_function_single_ipi(int cpu)
 {
-        return smp_call_function_on_cpu (func, info, retry, wait,
-                                         cpu_online_map);
+        send_ipi_message(cpumask_of_cpu(cpu), IPI_CALL_FUNC_SINGLE);
 }
-EXPORT_SYMBOL(smp_call_function);
 
 static void
 ipi_imb(void *ignored)