Jetpack/kernel/kernel-4.9/rt-patches/0228-idr-Use-local-lock-ins...

132 lines
3.3 KiB
Diff

From 401bb6f8c4d9663c106ceeac25bafaf5621f4cc7 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 14 Jul 2015 14:26:34 +0200
Subject: [PATCH 228/352] idr: Use local lock instead of preempt enable/disable
We need to protect the per cpu variable and prevent migration.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/idr.h | 4 ++++
lib/idr.c | 43 +++++++++++++++++++++++++++++++++++++------
2 files changed, 41 insertions(+), 6 deletions(-)
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 083d61e..5899796 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -95,10 +95,14 @@ bool idr_is_empty(struct idr *idp);
* Each idr_preload() should be matched with an invocation of this
* function. See idr_preload() for details.
*/
+#ifdef CONFIG_PREEMPT_RT_FULL
+void idr_preload_end(void);
+#else
static inline void idr_preload_end(void)
{
preempt_enable();
}
+#endif
/**
* idr_find - return pointer for given id
diff --git a/lib/idr.c b/lib/idr.c
index 6098336..9decbe9 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -30,6 +30,7 @@
#include <linux/idr.h>
#include <linux/spinlock.h>
#include <linux/percpu.h>
+#include <linux/locallock.h>
#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1)
#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
@@ -45,6 +46,37 @@ static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
static DEFINE_PER_CPU(int, idr_preload_cnt);
static DEFINE_SPINLOCK(simple_ida_lock);
+#ifdef CONFIG_PREEMPT_RT_FULL
+static DEFINE_LOCAL_IRQ_LOCK(idr_lock);
+
+static inline void idr_preload_lock(void)
+{
+ local_lock(idr_lock);
+}
+
+static inline void idr_preload_unlock(void)
+{
+ local_unlock(idr_lock);
+}
+
+void idr_preload_end(void)
+{
+ idr_preload_unlock();
+}
+EXPORT_SYMBOL(idr_preload_end);
+#else
+static inline void idr_preload_lock(void)
+{
+ preempt_disable();
+}
+
+static inline void idr_preload_unlock(void)
+{
+ preempt_enable();
+}
+#endif
+
+
/* the maximum ID which can be allocated given idr->layers */
static int idr_max(int layers)
{
@@ -115,14 +147,14 @@ static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr)
* context. See idr_preload() for details.
*/
if (!in_interrupt()) {
- preempt_disable();
+ idr_preload_lock();
new = __this_cpu_read(idr_preload_head);
if (new) {
__this_cpu_write(idr_preload_head, new->ary[0]);
__this_cpu_dec(idr_preload_cnt);
new->ary[0] = NULL;
}
- preempt_enable();
+ idr_preload_unlock();
if (new)
return new;
}
@@ -366,7 +398,6 @@ static void idr_fill_slot(struct idr *idr, void *ptr, int id,
idr_mark_full(pa, id);
}
-
/**
* idr_preload - preload for idr_alloc()
* @gfp_mask: allocation mask to use for preloading
@@ -401,7 +432,7 @@ void idr_preload(gfp_t gfp_mask)
WARN_ON_ONCE(in_interrupt());
might_sleep_if(gfpflags_allow_blocking(gfp_mask));
- preempt_disable();
+ idr_preload_lock();
/*
* idr_alloc() is likely to succeed w/o full idr_layer buffer and
@@ -413,9 +444,9 @@ void idr_preload(gfp_t gfp_mask)
while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
struct idr_layer *new;
- preempt_enable();
+ idr_preload_unlock();
new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
- preempt_disable();
+ idr_preload_lock();
if (!new)
break;
--
2.7.4