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ARC: [SMP] simplify IPI code

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* ipi_data is just a word, no need to keep it as struct

* find_next_bit() not needed to loop thru a 32bit word, ffs suffices
This commit is contained in:
Vineet Gupta 2013-11-26 15:23:44 +05:30
parent 53dc110c97
commit f2a4aa5646
1 changed files with 28 additions and 28 deletions
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56
arch/arc/kernel/smp.c
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@ -197,37 +197,31 @@ int __init setup_profiling_timer(unsigned int multiplier)
/* Inter Processor Interrupt Handling */
/*****************************************************************************/
/*
* structures for inter-processor calls
* A Collection of single bit ipi messages
*
*/
/*
* TODO_rajesh investigate tlb message types.
* IPI Timer not needed because each ARC has an individual Interrupting Timer
*/
enum ipi_msg_type {
IPI_NOP = 0,
IPI_EMPTY = 0,
IPI_RESCHEDULE = 1,
IPI_CALL_FUNC,
IPI_CPU_STOP
IPI_CPU_STOP,
};
struct ipi_data {
unsigned long bits;
};
/*
* In arches with IRQ for each msg type (above), receiver can use IRQ-id to
* figure out what msg was sent. For those which don't (ARC has dedicated IPI
* IRQ), the msg-type needs to be conveyed via per-cpu data
*/
static DEFINE_PER_CPU(struct ipi_data, ipi_data);
static DEFINE_PER_CPU(unsigned long, ipi_data);
static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)
{
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);
unsigned long flags;
pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);
local_irq_save(flags);
set_bit(msg, &ipi->bits);
set_bit(msg, ipi_data_ptr);
/* Call the platform specific cross-CPU call function */
if (plat_smp_ops.ipi_send)
@ -275,12 +269,11 @@ static void ipi_cpu_stop(void)
machine_halt();
}
static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi)
static inline void __do_IPI(unsigned long pending)
{
unsigned long msg = 0;
while (pending) {
do {
msg = find_next_bit(ops, BITS_PER_LONG, msg+1);
unsigned long msg = __ffs(pending);
switch (msg) {
case IPI_RESCHEDULE:
@ -294,8 +287,14 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi)
case IPI_CPU_STOP:
ipi_cpu_stop();
break;
default:
pr_warn("IPI missing msg\n");
}
} while (msg < BITS_PER_LONG);
pending &= ~(1U << msg);
}
}
/*
@ -304,9 +303,10 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi)
*/
irqreturn_t do_IPI(int irq, void *dev_id)
{
int cpu = smp_processor_id();
struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
unsigned long ops;
unsigned long pending;
pr_debug("IPI [%ld] received on cpu %d\n",
*this_cpu_ptr(&ipi_data), smp_processor_id());
if (plat_smp_ops.ipi_clear)
plat_smp_ops.ipi_clear(irq);
@ -315,8 +315,8 @@ irqreturn_t do_IPI(int irq, void *dev_id)
* XXX: is this loop really needed
* And do we need to move ipi_clean inside
*/
while ((ops = xchg(&ipi->bits, 0)) != 0)
__do_IPI(&ops, ipi);
while ((pending = xchg(this_cpu_ptr(&ipi_data), 0)) != 0)
__do_IPI(pending);
return IRQ_HANDLED;
}