2013-11-22 01:00:09 +00:00
|
|
|
From: Thomas Gleixner <tglx@linutronix.de>
|
|
|
|
Subject: idr: Use local lock instead of preempt enable/disable
|
2013-12-02 05:10:45 +00:00
|
|
|
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patches-3.12.1-rt4.tar.xz
|
2013-11-22 01:00:09 +00:00
|
|
|
|
|
|
|
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 | 37 ++++++++++++++++++++++++++++++++++---
|
|
|
|
2 files changed, 38 insertions(+), 3 deletions(-)
|
|
|
|
|
|
|
|
--- a/include/linux/idr.h
|
|
|
|
+++ b/include/linux/idr.h
|
|
|
|
@@ -92,10 +92,14 @@ void idr_init(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
|
|
|
|
--- a/lib/idr.c
|
|
|
|
+++ b/lib/idr.c
|
|
|
|
@@ -37,6 +37,7 @@
|
|
|
|
#include <linux/spinlock.h>
|
|
|
|
#include <linux/percpu.h>
|
|
|
|
#include <linux/hardirq.h>
|
|
|
|
+#include <linux/locallock.h>
|
|
|
|
|
|
|
|
#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1)
|
|
|
|
#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
|
|
|
|
@@ -389,6 +390,36 @@ int __idr_get_new_above(struct idr *idp,
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__idr_get_new_above);
|
|
|
|
|
|
|
|
+#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
|
|
|
|
+
|
|
|
|
/**
|
|
|
|
* idr_preload - preload for idr_alloc()
|
|
|
|
* @gfp_mask: allocation mask to use for preloading
|
|
|
|
@@ -423,7 +454,7 @@ void idr_preload(gfp_t gfp_mask)
|
|
|
|
WARN_ON_ONCE(in_interrupt());
|
|
|
|
might_sleep_if(gfp_mask & __GFP_WAIT);
|
|
|
|
|
|
|
|
- preempt_disable();
|
|
|
|
+ idr_preload_lock();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* idr_alloc() is likely to succeed w/o full idr_layer buffer and
|
|
|
|
@@ -435,9 +466,9 @@ 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;
|
|
|
|
|