mips: convert to generic helpers for IPI function calls

This converts mips to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single(). Not tested,
but it compiles.

mips shares the same IPI for smp_call_function() and
smp_call_function_single(), since not all mips platforms have enough
available IPIs to support seperate setups.

Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

3 files changed, 12 insertions, 131 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e5a7c5d96364..ea70d5a225ca 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1763,6 +1763,7 @@ config SMP
         bool "Multi-Processing support"
         depends on SYS_SUPPORTS_SMP
         select IRQ_PER_CPU
+        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/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index cdf87a9dd4ba..c75b26cb61df 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -131,148 +131,29 @@ asmlinkage __cpuinit void start_secondary(void)
         cpu_idle();
 }
 
-DEFINE_SPINLOCK(smp_call_lock);
-
-struct call_data_struct *call_data;
-
-/*
- * Run a function on all other CPUs.
- *
- *  <mask>      cpuset_t of all processors to run the function on.
- *  <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:
- *
- * CPU A                               CPU B
- * Disable interrupts
- *                                     smp_call_function()
- *                                     Take call_lock
- *                                     Send IPIs
- *                                     Wait for all cpus to acknowledge IPI
- *                                     CPU A has not responded, spin waiting
- *                                     for cpu A to respond, holding call_lock
- * smp_call_function()
- * Spin waiting for call_lock
- * Deadlock                            Deadlock
- */
-int smp_call_function_mask(cpumask_t mask, void (*func) (void *info),
-        void *info, int retry, int wait)
+void arch_send_call_function_ipi(cpumask_t mask)
 {
-        struct call_data_struct data;
-        int cpu = smp_processor_id();
-        int cpus;
-
-        /*
-         * Can die spectacularly if this CPU isn't yet marked online
-         */
-        BUG_ON(!cpu_online(cpu));
-
-        cpu_clear(cpu, mask);
-        cpus = cpus_weight(mask);
-        if (!cpus)
-                return 0;
-
-        /* Can deadlock when called with interrupts disabled */
-        WARN_ON(irqs_disabled());
-
-        data.func = func;
-        data.info = info;
-        atomic_set(&data.started, 0);
-        data.wait = wait;
-        if (wait)
-                atomic_set(&data.finished, 0);
-
-        spin_lock(&smp_call_lock);
-        call_data = &data;
-        smp_mb();
-
-        /* Send a message to all other CPUs and wait for them to respond */
         mp_ops->send_ipi_mask(mask, SMP_CALL_FUNCTION);
-
-        /* Wait for response */
-        /* FIXME: lock-up detection, backtrace on lock-up */
-        while (atomic_read(&data.started) != cpus)
-                barrier();
-
-        if (wait)
-                while (atomic_read(&data.finished) != cpus)
-                        barrier();
-        call_data = NULL;
-        spin_unlock(&smp_call_lock);
-
-        return 0;
 }
 
-int smp_call_function(void (*func) (void *info), void *info, int retry,
-        int wait)
+/*
+ * We reuse the same vector for the single IPI
+ */
+void arch_send_call_function_single_ipi(int cpu)
 {
-        return smp_call_function_mask(cpu_online_map, func, info, retry, wait);
+        mp_ops->send_ipi_mask(cpumask_of_cpu(cpu), SMP_CALL_FUNCTION);
 }
-EXPORT_SYMBOL(smp_call_function);
 
+/*
+ * Call into both interrupt handlers, as we share the IPI for them
+ */
 void smp_call_function_interrupt(void)
 {
-        void (*func) (void *info) = call_data->func;
-        void *info = call_data->info;
-        int wait = call_data->wait;
-
-        /*
-         * Notify initiating CPU that I've grabbed the data and am
-         * about to execute the function.
-         */
-        smp_mb();
-        atomic_inc(&call_data->started);
-
-        /*
-         * At this point the info structure may be out of scope unless wait==1.
-         */
         irq_enter();
-        (*func)(info);
+        generic_smp_call_function_single_interrupt();
+        generic_smp_call_function_interrupt();
         irq_exit();
-
-        if (wait) {
-                smp_mb();
-                atomic_inc(&call_data->finished);
-        }
-}
-
-int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
-                             int retry, int wait)
-{
-        int ret, me;
-
-        /*
-         * Can die spectacularly if this CPU isn't yet marked online
-         */
-        if (!cpu_online(cpu))
-                return 0;
-
-        me = get_cpu();
-        BUG_ON(!cpu_online(me));
-
-        if (cpu == me) {
-                local_irq_disable();
-                func(info);
-                local_irq_enable();
-                put_cpu();
-                return 0;
-        }
-
-        ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, retry,
-                                     wait);
-
-        put_cpu();
-        return 0;
 }
-EXPORT_SYMBOL(smp_call_function_single);
 
 static void stop_this_cpu(void *dummy)
 {
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c
index 3e863186cd22..a516286532ab 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c
@@ -877,7 +877,6 @@ static void ipi_resched_interrupt(void)
         /* Return from interrupt should be enough to cause scheduler check */
 }
 
-
 static void ipi_call_interrupt(void)
 {
         /* Invoke generic function invocation code in smp.c */